>Hi Ron!

I love your web site and I like your work very much!

Before I ask my questions, please tell anyone who might be interested that the G-Clarons -- I bought them on your recommendation -- are wonderful view camera lenses. I use the 210 and the 240 on my 8 x 10 camera. Soon I will add the 305 to my collection. The 210 covers an 8 x 10 wide open with move- ments! My guess is that its image circle is close to 400 mm, and is similar in its angle of view to a 28 mm lens on a 35 mm camera.

Here are my questions:

1. How do you protect the front element of your lenses from salt spray and blowing sand when you are shooting at the ocean? Do you use glass filters? Some photographers claim that glass filters are not as good as gelatin ones, and that glass filters, no matter how well they have been manufactured, will degrade image quality. Is this true?

2. Do you use Weston's ABC Pyro formula to develop your 8 x 10 Tri-X negatives? How would you compare, or rate, the Tri-X/HC 110 combination with Tri-X/ABC Pyro?

3. What enlarging paper and developer do you use? Do you use Amidol?

Thanks in advance for your comments.

Best regards,

Greg<

Dear Greg,

I certainly agree with your assesment of the G-Claron. It is the closest thing to an off the shelf Dagor type lens that we have today. I do not protect my lenes in any specail way. I just don't attempt to clean them in the field. A little dust will have no effect what so ever on the image. Salt spray could degrade the image somewhat depending upon how much got on the lens. I think a clear filter might not be a bad idea in such a case. You could compose through it, and then take it off just for the exposure.

Franky, after many bench tests, I have never been able to find any effects from the use of good quality glass filters, as long as they are used on the outside of the camera. Inside, behind the lens, can introduce some astigmatism. I have found from experience that some plastic filters are not especially good, but gels are, of course, the best.

I do not use the Weston version of the ABC pyro formula, but rather the original Kodak D-1 ABC forumula. The difference is that Weston reduced the carbonate somewhat to reduce the activity of the developer. I seem to recall that he often developed by inspection, and perhaps this gave him more time and latitude to do so (I invite comments from our readers on this subject). I have read his day books, and I am sure that the information is there but I do not recall specifically. To compare this old formula with a modern one, one would have to go with D-76 for the best match. I do not especially like HC-110 for my work because it seems to produce a long toe that does not favor outdoor contrast. This developer would be better, in my opinion, for studio lighting which stresses highlights

Ah, the paper question. Since the demise of Seagull, I have been on something of a search. I prefer single grade papers, and at this point, I am leaning toward Illford Gallery. I do not use Amidol.

>Ron,

I would appreciate any information or comments you may have regarding the suitability of the Turner Reich 300-475-625mm/f7-12.5-16 convertible lens for 8x10 portrait and landscape work. I have an opportunity to buy this lense combination, but I have not been able to find too much information on the net. The lens is mounted in Betax 4 synched press shutter and I would use it in an 8x10 Korona Home Portrait camera I restored. I attached a pic of the piece.

Can you help or point me in the right direction?

Thanks in advance!

Ed Kirkpatrick Ed Kirkpatrick Photography www.edkirkpatrick.com Gallery West Ltd www.gallery-west.com

Mr. Kirkpatrick,

The Turner Reich is a five element, cemented design very similar in concept and performance to the Dagor and Protar. The probability that the extra element in each group was added solely to avoid patent infringement is very high, since the patent date is only two years after the dates of other two lenses. The problem is that aligning the lens elements to a common axis, essential for the formula to perform to its optimum, is extremely difficult. Misaligned elements cause zonal "decentration astigmatism". Three or four elements, as in the case of the Dagor and Protar, is difficult enough, but the addition of yet a fifth element to align almost guarantees that there will be some degree of error. If one tests any five Turner Reich lenses, my experience is one of them will be quite good, the others will probably have some degree of decentration aberration. The only way to tell is to do a bench test. Really, though, stopping down to f:32 will ameliorate the ills to a large extent, and many photographers use the Turner Reich lenses very happily, especially if they are shooting on 8x10. I personally use one 900mm cell along with my Protars, since Zeiss never made production 900s. I did have to completely disassemble the lens and recement it to correct the alignment, but now is performs quite well.

>Hello Mr. Wisner......I search around for information on Protars and your name always comes up....perhaps you can help...I am looking at a Zeiss Protar Vll. I am told it's a double convertable..the front and rear lens groups show 290cm.and when used together they give 145 or150 cm.,...I can't remember which. Does this sound correct? If so my concern is will this lens cover my 5x7?...particularly the shorter focal length. Thanks so much for your time......Q.M.<

Mr. Molyn,

I have not used my 4x5 Protars for a while, but if memory serves, two 290mm cells make a 163mm double. If you refer to the lens coverage table in the articles index on this web site, you will see that the 163mm on 5x7 only comes to about 65 degrees. Since the Protars are 80 degree lenses, this focal length will cover 5x7 easily.

Here's a trick that you can use in the future to determine the focal length of an unknown lens: Take a lens of known focal length. Focus the image on a distant object like a house. Measure the object on the ground glass carefully in one dimension. Now take the unknown lens and focus on the object again. Measure the object on the ground glass, again, very carefully. Now simply do a proportional calculation:

Object image 1/focal length 1 = Object image 2/unknown focal length.

Solve the unknown by cross-multiplying and dividing. Focal length 1 times object image 2, divided by obect image 1 equals the unknown focal length. If you do the measurements precisely the answer will be very accurate. Be sure you use a distant object so that you don't get a magnification ratio error.

One note of caution: Sometimes a lens of a nominal focal length is actually some close fractional focal length. In other words, a lens engraved 150mm might actually be 148.5mm. Check with your manufacturer for this information. For practical purposes and for calculating f/stops, this kind of error is insignificant.

>Ron,

I purchased the above camera from you about a week ago and I have been contemplating the need for film holders. I am interested in film holders for standard film and Polaroid film. Basically, I will be using both color and b&w films with the main emphasis on color. What Polaroid film do you recommend for both color and b&w. I see you sale both film holders. Why is the Polaroid backing so much more expensive? How many sheets of film can you place in the standard holder? How many in the Polaroid holder? Are they easy to use? As stated in a previous message, I have never used a large format cameras nor have I loaded any film into film holders. I currently own a Shadow Box 4x5 film changing tent which will be used for everything from loading film to developing film.

Thanks for your time and suggestions,

...Thomas Earle...<

Dear Mr. Earle,

As far as I am aware, there is only one color film available in the sleeve type package from Polaroid at this time, and that would be type 59. The black and white film of choice for me is always the type 55 P/N. I love this film. It is very sharp, has beautiful gradation, and gives you an instant negative. The sleeves, which are packaged around types 54, 55 and 59, are used in the 545 holder. This system allows you to make one exposure at a time and develope it immediately. The reason the Polaroid holder is so expensive is due to the precision rollers which develope the film, and the various other mechanical parts to open and close the rollers, release the film and so forth.

In any case, it shouln't take long to get used to the holder and the Polaroid system, and I find it an important part of my arsenal. Virtually all of the product photos used on the web and in our catalog are taken on Polaroid film, except for some of the color.

I've read many times that when using a single cell from a convertible lens, that single cell should always be used behind the shutter, but I've never read an explanation why this should be. What are the negative effects of using a single cell in front of the shutter? Thanks. <

Dear Mr. LeBlanc,

The reason is very simple, really. Some of this, parenthetically, relates to my article on "flat field" lenses, which you can find in the articles index on this site.

A convertible lens is almost always symmetrical or hemi-symmetrical (meaning a scaled, exact copy of the other cell, just larger or smaller). This means that theoretically, the lens is really a 1:1 lens, although we use them at all magnifications. I am speaking here of all of the so-called "double anastigmat" lenses, such as Dagors, Protars, convertible Symmars, Wollensak convertibles, early convertible Plasmats, Collinears and so forth. Most of these were designed even before the turn of the century (pretty soon we will have to specify which turn of the century). We all know that these lenses are used at every magnification ratio, but most often at normal distances. It may not be recognized by modern photographers,that since these lenses are symmetrical, they are indeed quite good as macro and 1:1 lenses. As such, when one does a ray trace, you will find that the rays in the air space are parallel when the lens is used at 1:1. Since this condition is the optimum for a lens which is symmetrical, it makes sense that if we remove the front element to use a single cell, that the parallel rays entering the rear cell at infinity or near-infinity distances mimick the conditions at 1:1. This helps to minimize the aberrations.

One other argument for the lens behind the shutter has to do with the nature of the distortion when one uses a single cell. Since symmetry automatically corrects distortion, some small amount distortion is re-introduced when one uses a single cell. Some argue that the barrel distorion resulting from the rear position is less objectionable than the pin-cushion variety which occurs with the cell in front.

Now here is the disclaimor: If I suddently find, for some reason, that I need more extension than the bellows will allow (perhaps I am close to my subject), I will put the cell in the front! This places the node of the lens out in front of the cell, and shortens the extension as much as 25%. I have tested the lenses both ways, and although the rear postion is better, the front position is usable. I would just stop down a little more to help correct any aberrations which may have increased.

Is there anything accessory that might be needed to handle the 75 mm lens? I have not focussed on groundglass before. Would it be better to replace the included groundglass with a Bosscreen or Beattie Intenscreen? Are they worth the extra $150? Are they hard to install into your cameras? I believe, I will likely need a focusing cloth. Is there one that you would recommend? In addition, I fear, I may need a center filter, especially for the 75 mm. I was thinking about going with the cheaper Heliopan filters but do not know if I need to choose the 1 1/2 stop or 3 stop filter. It appears they are measured by their front accessory size. Would that be 67 mm for my Nikkor lenses (i.e., 75 and 90 mm)? I see that most are made for f/16. What happens if you shoot at f/22 or smaller?

If there are any additional accessories I might need please let me know.

Thanks,

...Wade... <

Dear Wade,

Both lenses you chose will work fine on the Pocket Expedition without the additional bag bellows. As for the viewing screens, I would personaly choose a plain fresnel to add to the existing ground glass. It will work as well as the proprietary screens you mention. As for using the center filters at f:16, this only means that you want to use at least f:16 or smaller to avoid mechanical vignetting. This would be true in most cases anyway.

To: Mr. Ron Wisner;

I'm am planning to move up to large format by the end of this year and I'm currently at that stage of considering all the available equipment options before plunking down the cash for this endeavor. While your Q and A postings continue to be a terrific source for technical and aesthetic information, I was hoping you might indulge me in answering a simple practical question regarding the carrying weight of the gear. At this point I am hopeful of owning an 8x10 field camera, but I've certainly not closed the door on making my choice a 4x5. I would simply like to ask how much weight could one expect to carry with one of your f/64 backpacks containing the 8x10 Traditional-L Camera, two lenses, 3 or 4 film holders, (is there room in the f/64 for holders?), dark clothe, spot meter, tripod and perhaps 5 pounds of the other usual necessities? I'm aware that's it's a beginner's question, but not personally knowing someone who owns said equipment I don't now where else to turn for an answer. Any light either you or one of your many readers can shed on this basic matter would be very much appreciated. With gratitude......Vernon Kifer.....Glendale, California.<

Dear Mr. Kifer,

You may be getting a biased answer from me on this one, since I am a hard core 8x10 shooter. I have to go back to 4x5 when I do product shots for the company, and when I do it always feels like a miniature format. To your specific question, how much you carry depends upon how big you are and what kind of shape you are in. I have always felt that what we do helps keep us young. Like conductors who live into their 80s and 90s because they are always waving thier arms about, carrying a big camera keeps you young. The bigger the camera, the younger you'll stay. When Chuck Farmer and I climbed Mt. Whitney, we each carried about 55 lbs. Granted, this included our camping gear and all the camera equipment. I weighed my own camera case just now, and it weighs 37 lbs. This includes the 8x10 Expedition, all my lenses, light meter, three holders, dark cloth and the case itself. I would usually carry this on my back, and hand-carry the tripod if I am just making day hikes or sojourns from the car. If I were doing serious hiking, I would strap it to my back pack. There is room for the holders and several lenses, but I would definitely make a conscious effort to choose small lenses, either G-Claron types or the older Dagor types, which are about the same size. I also use a number of the tiny wide angle Series V f:18 Zeiss Protars which are all about the diameter of a quarter. This saves a huge amount of weight and space. Finally, I only carry three filters: #15 orange, #23 red and #25 red. They are all larger than my largest lens, and I use step up filters to adapt them to the various lenses in my outfit.

I hope this helps with your decision making.

Message text written by "Flynn, John" >

Ron: Thanks for agreeing to entertain my questions. The text of my inquiry follows: After recently re-reading Joe Englander's article on film holders in the April 1995 issue of Camera and Darkroom, I bought a depth micrometer and began checking my film holders. The article stated that the ANSI standard depth of a film holder is 0.197 inches. He said this provides for a film thickness of 0.007 inches. My film holders were as innacurate as the article predicted. My primary camera is a Toyo 45A 4X5 field camera, which I bought new in 1986. I decided to check its back to determine whether the distance from the milled mating surfaces of the back to the ground glass plane is 0.190 inches, as Joe's article suggested it ought to be. The back has a fresnel lens on the side of the ground glass toward the lens, with the rings on the side which touches the ground glass. In the center of the Fresnel lens is a clear spot, which appears to me to be optically flat. This provides a clear central area for critical focusing. I disassembled the sandwich and drilled a 1/4" hole in the middle of the clear area of the Fresnel lens. I reassembled the back and measured the depth, through the hole, from the machined mating surfaces of the back to the surface of the ground glass. My measurement is 0.206 inches. I then checked the focus. I noted that if I focus the image on the ground glass through the hole in the Fresnel lens, I have to move the lens further from the camera back in order to focus the image on the clear center area of the Fresnel lens. I could tell from this experiment that the focus plane with the Fresnel lens in place is not on the surface of the ground glass. I was not able to determine with my equipment exactly where in the sandwich the focus plane lies. Here are my questions, should you be kind enough to help:

1. Would the presence of the Fresnel lens create a need to depart from the specified 0.190 inch standard, because of some optical effect of the Fresnel lens? If so, how do camera makers calculate this effect when they design camera backs? 2. If the Fresnel lens is not creating its own optical effect, then my camera appears to be out of specification. Would this 0.016" error, coupled with the errors in some of my Riteway film holders (some as much as 0.015 in the other direction), create a noticeable lack of sharpness? (I focus very critically). 3. If yes, then should I place the ground glass 0.190 inches from the mating surfaces of the back? 4. I gather from other readings that you are not a proponent of placing Fresnel lenses in front of the ground glass. Is there a better setup that I might pursue? 5. It seems to me that the Fresnel lens is only causing me problems. Could I get rid of it and shim my ground glasss into the proper position? 6. Something else I've wanted to ask you for a long time: For very critical focusing, I use a 25X hand microscope from Edmund Scientific. It looks like a fountain pen, and has a plastic cone on the base, which slides to vary the focus point. I set the cone to focus on the ground side of the ground glass, and epoxied it in that postion and painted it black. It works great in the field. The question is, can I drill a 1/4" hole in the ground glass and use the microscope to focus on the aerial image? I've done some rough experiments which suggest that this would work. What do you think? <

Dear John,

The error in your ground glass/fresnel system is exactly the one I have railed about for years. The fresnel should NEVER be in front of the ground glass, and you have just proved why. Any substrate of appreciable optical index in the ray path will displace the focused image. If the index is about 1.5, such as in acrylic or glass, the displacement will be about 1/3 the thickness of the materail, which you just showed. The problem gets worse as you depart from the axis, because the thickness of acrylic the ray path has to traverse is greater because of the angle. This results in an apparent image field curvature that does not exist, and will cause you to focus eroneously in the corners.

With due respect to Joe Englander, nothing in the ASA/ISO standards provides for the film thickness. The standards simply dictate the dimensions of the holders and the allowable tolerances. It is up the the camera manufacturer to calculate the film thickness and set the ground glass accordingly. At the Wisner Company we are particularly picky about the ground glass plane. We subtract .005" from the film holder septum position. We do this because there are some films used in sheet film holders which are not the full .008" of the Estar based films. Furthermore, this leaves about .002" of material which can wear over the years and still be in focus. We have a special bar with a dial indicater mounted in the middle, and each and every ground glass is hand focused by lapping on a granite stone covered with fine abrasive. We check the entire surface with the guage before the ground glass frame is passed.

I would definitely remove the fresnel and re-set the ground glass by whatever means possible at .192". If you wish, you may then place the fresnel on the OUTSIDE of the camera and ground glass, where it belongs.

As for your final question, I do think the 25x focuser is a little overkill. It may acutally exceed the diffraction limit and probable enlargment magnification of your prints in your usual working apertures. Example: if you shoot at f:22, the diffraction limit is about 68 lines/mm. With magnification of 25x, you will be effectively looking at 2.7 lines through the scope, which is double the 6 lines limit of normal human vision at a 10 inch reading distance. It also implies that you are going to make 25x enlargements or 100 x 125 inch prints. I think you will find it frustrating to focus to such a standard.

Message text written by Bob Cassanova

> I have the Wisner 4x5 Technical Field camera that I enjoy using and have a question about macro photography. I have a 210 mm f9 G-Claron lens and have been using a Nikon 6T close-up attachment. The advantage of using the 6T are that long extensions are not required to achieve 1:1 or greater magnefication which yields much brighter images for focusing. I normally stop down to at least f22 to expose the film. Do you have an opinion, or any data, about this combination, such as image distortion, resolution, etc. as compared to using the lens alone with much longer extensions??

Dear Mr. Cassanova,

Since the aperture is a ratio of the opening of the lens divided into the focal length, anything that shortens the focal length (which is what supplementary close-up lenses do) by adding postitive power, will result in a faster f-stop. I am not sure, however, that this result is worth the compromise in sharpness which almost always comes from disturbing the balance of the system. You probably are adding some aberrations to the system by using these supplemtary lenses, but the only way to be sure would be to do a bench test.

Remember also, that if you are shooting at anything other than infinity, not only is the focal length changing to some effective focal length longer than the one egraved on the lens, but as a result, so is the effective aperture changing. You now have a compound problem. You have changed the apterure by virtue of the added lens, and you have an effective f-stop that has also changed due to your magnification ratio.

I would ask you how you are calculating your exposure. Are you metering through the lens? Are bracketing? I would do the following if you want to use this combination:

1) Put the supplementary lens on and focus at infinity. Measure the new focal distance from the front standard. ( You will be changing the node somewhat, but measuring from the lens board should be close enough) I don't know the power of your Nikon "6t" close up attachment, but suppose it is 6 diopters. Diopters are additive, so lets say you have 6 diopters plus the 210 which is a 4.7 diopter lens, equals 10.76 diopters. Since the diopter power is the reciprocal of the fraction a meter (1 meter equals 1 diopter), and the reciprocal is .092, the focal length of your system is now 92mm. This all assumes that you are using a 6 diopter attachment, which you haven't told me.

2) Calculate the actual opening at the unconverted aperture: in other words, if the lens is set at f:22, divide 210mm by 22 and you get 9.54mm. Now divide 9.54mm into the new focal length as measured above. The result is f:9. Again, this all assumes that my calculation based upon a 6 diopter lens is correct. When you measure your focal length you may find it is some other value.

3) The f:9 aperture is the effective aperture at infinity. If you are working at any distance other than infinity , you would perform the same measurement and calculation: measure the focal distance, then divide the aperture opening, in this case 9.54mm (if you are set at f:22 on the scale) into the focal length as measured. The answer will be your effective f:stop. If I am right about the converted focal length of 92mm, and you are focused at 1:1, your effective focus will be 184mm, and the effective f-stop will be f:19.28. This is the value you will use on your meter.

Hi Ron,

Before, I ask the question, I have to tell you that your the web site is great. My God .... atop the Golden Gate Bridge with you 8x10 .... I can go up any heigth as long as I keep one foot on the ground. Unbelievable .... would have scared the hell out of me and then some.

Now for my question ... I am thinking of adding a 300/305 lens to my 4x5 system (Wisner of course ... the same one you brought me down in Natchez). Assuming the $ are not the issue ... which of the Schneiders do you recommend? Also, I believe their is some type of sale going now .... what can you do for me on either.

Thanks and best regards,

Henry

Henry Farnam<

Henry,

I think the best choice for your 4x5 is the 305 G-Claron. It's light, sharp,and has a large angle.

I may have been blessed in some ways, but spelling ability is not one of them. For those of you who can spell, like my grandmother, you will never understand those of us who can not. Like morning people or people who don't eat sweets, there is an unspoken moral superiority of poeple who can spell. Some of you may have noticed that I often amend my online answers. When I do I am frequently horrified at the spellings that I find I have used. And those are the ones I notice! On the other hand, there are words that I am quite sure of because of distinctions of meaning, philosophy or etymology. I offer the following exchange for the sake of a little humor and in defense of all the smart people out there who can't spell. ---Ron Wisner

>Ron-

I read through your articles, and I have a couple of questions about this one. What is the 'esthetic vision' that you refer to in the upper portion, and how does it relate to something I could define, 'aesthetic vision'? I would crudely define it as the way in which a viewer considers a physical vision with a mental ideal in a broad comparison of completion. How does 'esthetic vision' differ? Is this a term particular to photography?

I also thought this was rather clever: 'Photographers, like people, differ'. I am going to take a guess that you are asserting that there are some photographers who think they are something more than just people, eh? I guess we get them in every industry.

Dave<

Dear Dave,

The Greek origin of the word esthetic (i.e. aesthetic) is "aistetikos", of sense perception, originally more at "audible". The modern evolution of the meaning has, of course, changed to include all perceptions, and ultimately an appreciation of the beautiful, although this is somewhat an old fashioned (pre-war) notion. The English proclivity to combine the "ae" vowels for Greek words reflects the Germanic origins of English, in which the Greek pronunciation and vowels were imitated in German with an umlaut over the "a". In Enlgish, of course, there is no umlaut, so as is the common practice when transribing German to English, the "a" has an "e" attached to it to take the place of the umlaut. This is also why one sees the odd combination of "oe" in so many anglicized German names and words. In the American language it is has been deemed acceptable for phonetic reasons to drop the vestigial "a", though both spellings, of course, are correct.

As for photographers differing from people, they certainly are a different subset. Kind of like saying "squares like [other] rectangles...".

I hope this clears things up for you....

>Ron,

I have located a Rodenstock Geronar-WA 90mm f8. The lens is lighter than the one I am using and is in excellent condition for $400.00. Whatta you think?

Mitchell A. Russo Sudbury, MA 01776 <

Dear Mitchell,

I fear because I am behind in my Q&A postings that my advice may not be in time for you. But nevertheless, this is a good lens, though not as well endowed in coverage as others might be. If I recall correctly, it covers about 85 degrees (maybe 90, but I am not positive), and it is capable of being extremely sharp. This is a modern example of the well known and fairly old double Gauss meniscus design. This design (positive, negative, negative, positive front to back) is a symetrical (or nearly so) arrangement of menicus elements about the central stop. The concept, as a photographic lens, goes all the way back to the Hypergon which was an extreme wide angle two menscus lens. One might even make the argument for the Planar of 1897 as being in the same family, but this was not a wide angle lens. This lens type, which includes the Metrogon, the Rectagon, the Cooke Series VII Wide Angle, the Kodak Wide Field Ektar and the Meyer Weitwinkel (wide angle) Anastigmat, to name just a few, several of which cover up to and over 100 degrees, are charactorized by very flat fields and low astigmatism. The draw back with this lens was always the oblique spherical aberration at wide apertures in the older examples. This is cured by the user by simply stopping down, whereupon it goes away. What's left is a very good optic with good field flatness. Your lens is a modern, coated lens, and its a good thing, because the other big problem with this type is the absolute necessity for the lens to be coated, since it has eight air-to-glass surfaces. This renders older, uncoated examples nearly useless, in my opinion. This very reason is the fact that facilitated the perpetuation of other types of wide angle lenses that did not have such flat fields, such as the little Protar Series V.

>Dear Ron,

I am slowly coming to grips with my Wisner 8 x 20 back. I thought the move from 8 x 10 upwards would be fairly easy, but there is a surprising amount of detail and technique to re-learn at 8 x 20.

Lens coverages:

I thought I would let you know that the 355 f9 G-Claron DOES cover 8 x 20, and is a realy nice lens for the format. It is sharp right to the edges. However, it really does need a centre filter. Developing negs to N contrast for silver printing does not show up any significant density differences between centre and edges. However, develop the neg to N+2 for Pt/Pd and the light fall off is so significant as to ruin the neg.

The Nikkor 450M f9 also covers 8 x 20, however it is nowhere near as sharp at the edges as the G Claron. It really needs stopping down to to f 64 or smaller to get anything half decent.

The 600 f11.5 Apo Germinar also covers the format easily.

Hope you find this of interest, please pass it on to other large format users.

Is anyone interested in gettng together a Kodak order for 8 x 20 TRI-X ???

Regards,

Rob Nayler, Herefordshire, England <

Dear Dr. Nayler,

Thank you for your comments. I will indeed place them on the web for the benefit of our readers. I am not at all surprised at your comments regarding the 450m Nikor, since this is a Tessar type lens and as such would experience significant astigmatism and some lateral color as it approaches about 60 degrees, which is about what this combination represents.

> Ron,

The Symmar-S 135mm is my usual first choice with 4x5, and I'm looking for a lens with similar characteristics when I step up to 8x10. Since I read your comments that the G-Claron's image angle is closer to 80 degrees than the 64 degree specification Schneider lists, I've been considering the 270mm as my first choice for the larger format. Is there a formula I can use for calulating the useful image circle of this lens? Are there other lenses of the same focal length I should be considering?

Thanks,

Dear Mr. Phillips,

There are indeed formulas for calculating the image circle of any lens. If you know the angle of view (opticians sometimes call this the "image height"), then you can use a little trigonometry to figure the resulting relationship with any focal length and format. Rather than subject everyone to a tedious mathematics excerise, I offer herewith a table which I calculated for all common focal lengths and formats. Just use it as a look up table. Find the format across the top, then match it to the focal length on the left. The number where they meet is the angle in degrees that would result. If you know the angle of view of the lens as per published specs, you will then know if the lens will cover that condition.

As for other similar performing lenses, I certainly would consider any Dagor type lens in that range.

To: Mr. Ron Wisner;

I'm am planning to move up to large format by the end of this year and I'm currently at that stage of considering all the available equipment options before plunking down the cash for this endeavor. While your Q and A postings continue to be a terrific source for technical and aesthetic information, I was hoping you might indulge me in answering a simple practical question regarding the carrying weight of the gear. At this point I am hopeful of owning an 8x10 field camera, but I've certainly not closed the door on making my choice a 4x5. I would simply like to ask how much weight could one expect to carry with one of your f/64 backpacks containing the 8x10 Traditional-L Camera, two lenses, 3 or 4 film holders, (is there room in the f/64 for holders?), dark clothe, spot meter, tripod and perhaps 5 pounds of the other usual necessities? I'm aware that's it's a beginner's question, but not personally knowing someone who owns said equipment I don't now where else to turn for an answer. Any light either you or one of your many readers can shed on this basic matter would be very much appreciated. With gratitude......Vernon Kifer.....Glendale, California.<

Dear Mr. Kifer,

You may be getting a biased answer from me on this one, since I am a hard core 8x10 shooter. I have to go back to 4x5 when I do product shots for the company, and when I do it always feels like a miniature format. To your specific question, how much you carry depends upon how big you are and what kind of shape you are in. I have always felt that what we do helps keep us young. Like conductors who live into their 80s and 90s because they are always waving thier arms about, carrying a big camera keeps you young. The bigger the camera, the younger you'll stay. When Chuck Farmer and I climbed Mt. Whitney, we each carried about 55 lbs. Granted, this included our camping gear and all the camera equipment. I weighed my own camera case just now, and it weighs 37 lbs. This includes the 8x10 Expedition, all my lenses, light meter, three holders, dark cloth and the case itself. I would usually carry this on my back, and hand-carry the tripod if I am just making day hikes or sojourns from the car. If I were doing serious hiking, I would strap it to my back pack. There is room for the holders and several lenses, but I would definteley make a conscious effort to choose small lenses, either G-Claron types or the older Dagor types, which are about the same size. I also use a number of the tiny wide angle Series V f:18 Zeiss Protars which are all about the diameter of a quarter. This saves a huge amount of weight and space. Finally, I only carry three filters: #15 orange, #23 red and #25 red. They are all larger than my largest lens, and I use step up filters to adapt them to the various lenses in my outfit.

I hope this helps with your decision making.

Message text written by "Flynn, John" >

Ron: Thanks for agreeing to entertain my questions. The text of my inquiry follows: After recently re-reading Joe Englander's article on film holders in the April 1995 issue of Camera and Darkroom, I bought a depth micrometer and began checking my film holders. The article stated that the ANSI standard depth of a film holder is 0.197 inches. He said this provides for a film thickness of 0.007 inches. My film holders were as innacurate as the article predicted. My primary camera is a Toyo 45A 4X5 field camera, which I bought new in 1986. I decided to check its back to determine whether the distance from the milled mating surfaces of the back to the ground glass plane is 0.190 inches, as Joe's article suggested it ought to be. The back has a fresnel lens on the side of the ground glass toward the lens, with the rings on the side which touches the ground glass. In the center of the Fresnel lens is a clear spot, which appears to me to be optically flat. This provides a clear central area for critical focusing. I disassembled the sandwich and drilled a 1/4" hole in the middle of the clear area of the Fresnel lens. I reassembled the back and measured the depth, through the hole, from the machined mating surfaces of the back to the surface of the ground glass. My measurement is 0.206 inches. I then checked the focus. I noted that if I focus the image on the ground glass through the hole in the Fresnel lens, I have to move the lens further from the camera back in order to focus the image on the clear center area of the Fresnel lens. I could tell from this experiment that the focus plane with the Fresnel lens in place is not on the surface of the ground glass. I was not able to determine with my equipment exactly where in the sandwich the focus plane lies. Here are my questions, should you be kind enough to help:

1. Would the presence of the Fresnel lens create a need to depart from the specified 0.190 inch standard, because of some optical effect of the Fresnel lens? If so, how do camera makers calculate this effect when they design camera backs? 2. If the Fresnel lens is not creating its own optical effect, then my camera appears to be out of specification. Would this 0.016" error, coupled with the errors in some of my Riteway film holders (some as much as 0.015 in the other direction), create a noticeable lack of sharpness? (I focus very critically). 3. If yes, then should I place the ground glass 0.190 inches from the mating surfaces of the back? 4. I gather from other readings that you are not a proponent of placing Fresnel lenses in front of the ground glass. Is there a better setup that I might pursue? 5. It seems to me that the Fresnel lens is only causing me problems. Could I get rid of it and shim my ground glasss into the proper position? 6. Something else I've wanted to ask you for a long time: For very critical focusing, I use a 25X hand microscope from Edmund Scientific. It looks like a fountain pen, and has a plastic cone on the base, which slides to vary the focus point. I set the cone to focus on the ground side of the ground glass, and epoxied it in that postion and painted it black. It works great in the field. The question is, can I drill a 1/4" hole in the ground glass and use the microscope to focus on the aerial image? I've done some rough experiments which suggest that this would work. What do you think? <

Dear John,

The error in your ground glass/fresnel system is exactly the one I have railed about for years. The fresnel should NEVER be in front of the ground glass, and you have just proved why. Any substrate of appreciable optical index in the ray path will displace the focused image. If the index is about 1.5, such as in acrylic or glass, the displacement will be about 1/3 the thickness of the materail, which you just showed. The problem gets worse as you depart from the axis, because the thickness of acrylic the ray path has to traverse is greater because of the angle. This results in an apparent image field curvature that does not exist, and will cause you to focus eroneously in the corners.

With due respect to Joe Englander, nothing in the ASA/ISO standards provides for the film thickness. The standards simply dictate the dimensions of the holders and the allowable tolerances. It is up the the camera manufacturer to calculate the film thickness and set the ground glass accordingly. At the Wisner Company we are particularly picky about the ground glass plane. We subtract .005" from the film holder septum position. We do this because there are some films used in sheet film holders which are not the full .008" of the Estar based films. Furthermore, this leaves about .002" of material which can wear over the years and still be in focus. We have a special bar with a dial indicater mounted in the middle, and each and every ground glass is hand focused by lapping on a granite stone covered with fine abrasive. We check the entire surface with the guage before the ground glass frame is passed.

I would definitely remove the fresnel and re-set the ground glass by whatever means possible at .192". If you wish, you may then place the fresnel on the OUTSIDE of the camera and ground glass, where it belongs.

As for your final question, I do think the 25x focuser is a little overkill. It may acutally exceed the diffraction limit and probable enlargment magnification of your prints in your usual working apertures. Example: if you shoot at f:22, the diffraction limit is about 68 lines/mm. With magnification of 25x, you will be effectively looking at 2.7 lines through the scope, which is double the 6 lines limit of normal human vision at a 10 inch reading distance. It also implies that you are going to make 25x enlargements or 100 x 125 inch prints. I think you will find it frustrating to focus to such a standard.

Message text written by Bob Cassanova

> I have the Wisner 4x5 Technical Field camera that I enjoy using and have a question about macro photography. I have a 210 mm f9 G-Claron lens and have been using a Nikon 6T close-up attachment. The advantage of using the 6T are that long extensions are not required to achieve 1:1 or greater magnefication which yields much brighter images for focusing. I normally stop down to at least f22 to expose the film. Do you have an opinion, or any data, about this combination, such as image distortion, resolution, etc. as compared to using the lens alone with much longer extensions??

Dear Mr. Cassanova,

Since the aperture is a ratio of the opening of the lens divided into the focal length, anything that shortens the focal length (which is what supplementary close-up lenses do) by adding postitive power, will result in a faster f-stop. I am not sure, however, that this result is worth the compromise in sharpness which almost always comes from disturbing the balance of the system. You probably are adding some aberrations to the system by using these supplemtary lenses, but the only way to be sure would be to do a bench test.

Remember also, that if you are shooting at anything other than infinity, not only is the focal length changing to some effective focal length longer than the one egraved on the lens, but as a result, so is the effective aperture changing. You now have a compound problem. You have changed the apterure by virtue of the added lens, and you have an effective f-stop that has also changed due to your magnification ratio.

I would ask you how you are calculating your exposure. Are you metering through the lens? Are bracketing? I would do the following if you want to use this combination:

1) Put the supplementary lens on and focus at infinity. Measure the new focal distance from the front standard. ( You will be changing the node somewhat, but measuring from the lens board should be close enough) I don't know the power of your Nikon "6t" close up attachment, but suppose it is 6 diopters. Diopters are additive, so lets say you have 6 diopters plus the 210 which is a 4.7 diopter lens, equals 10.76 diopters. Since the diopter power is the reciprocal of the fraction a meter (1 meter equals 1 diopter), and the reciprocal is .092, the focal length of your system is now 92mm. This all assumes that you are using a 6 diopter attachment, which you haven't told me.

2) Calculate the actual opening at the unconverted aperture: in other words, if the lens is set at f:22, divide 210mm by 22 and you get 9.54mm. Now divide 9.54mm into the new focal length as measured above. The result is f:9. Again, this all assumes that my calculation based upon a 6 diopter lens is correct. When you measure your focal length you may find it is some other value.

3) The f:9 aperture is the effective aperture at infinity. If you are working at any distance other than infinity , you would perform the same measurement and calculation: measure the focal distance, then divide the aperture opening, in this case 9.54mm (if you are set at f:22 on the scale) into the focal length as measured. The answer will be your effective f:stop. If I am right about the converted focal length of 92mm, and you are focused at 1:1, your effective focus will be 184mm, and the effective f-stop will be f:19.28. This is the value you will use on your meter.

Hi Ron,

Before, I ask the question, I have to tell you that your the web site is great. My God .... atop the Golden Gate Bridge with you 8x10 .... I can go up any heigth as long as I keep one foot on the ground. Unbelievable .... would have scared the hell out of me and then some.

Now for my question ... I am thinking of adding a 300/305 lens to my 4x5 system (Wisner of course ... the same one you brought me down in Natchez). Assuming the $ are not the issue ... which of the Schneiders do you recommend? Also, I believe their is some type of sale going now .... what can you do for me on either.

Thanks and best regards,

Henry

Henry Farnam<

Henry,

I think the best choice for your 4x5 is the 305 G-Claron. It's light, sharp,and has a large angle.

I may have been blessed in some ways, but spelling ability is not one of them. For those of you who can spell, like my grandmother, you will never understand those of us who can not. Like morning people or people who don't eat sweets, there is an unspoken moral superiority of poeple who can spell. Some of you may have noticed that I often amend my online answers. When I do I am frequently horrified at the spellings that I find I have used. And those are the ones I notice! On the other hand, there are words that I am quite sure of because of distinctions of meaning, philosophy or etymology. I offer the following exchange for the sake of a little humor and in defense of all the smart people out there who can't spell. ---Ron Wisner

>Ron-

I read through your articles, and I have a couple of questions about this one. What is the 'esthetic vision' that you refer to in the upper portion, and how does it relate to something I could define, 'aesthetic vision'? I would crudely define it as the way in which a viewer considers a physical vision with a mental ideal in a broad comparison of completion. How does 'esthetic vision' differ? Is this a term particular to photography?

I also thought this was rather clever: 'Photographers, like people, differ'. I am going to take a guess that you are asserting that there are some photographers who think they are something more than just people, eh? I guess we get them in every industry.

Dave<

Dear Dave,

The Greek origin of the word esthetic (i.e. aesthetic) is "aistetikos", of sense perception, originally more at "audible". The modern evolution of the meaning has, of course, changed to include all perceptions, and ultimately an appreciation of the beautiful, although this is somewhat an old fashioned (pre-war) notion. The English proclivity to combine the "ae" vowels for Greek words reflects the Germanic origins of English, in which the Greek pronunciation and vowels were imitated in German with an umlaut over the "a". In Enlgish, of course, there is no umlaut, so as is the common practice when transribing German to English, the "a" has an "e" attached to it to take the place of the umlaut. This is also why one sees the odd combination of "oe" in so many anglicized German names and words. In the American language it is has been deemed acceptable for phonetic reasons to drop the vestigial "a", though both spellings, of course, are correct.

As for photographers differing from people, they certainly are a different subset. Kind of like saying "squares like [other] rectangles...".

I hope this clears things up for you....

>Ron,

I have located a Rodenstock Geronar-WA 90mm f8. The lens is lighter than the one I am using and is in excellent condition for $400.00. Whatta you think?

Mitchell A. Russo Sudbury, MA 01776 <

Dear Mitchell,

I fear because I am behind in my Q&A postings that my advice may not be in time for you. But nevertheless, this is a good lens, though not as well endowed in coverage as others might be. If I recall correctly, it covers about 85 degrees (maybe 90, but I am not positive), and it is capable of being extremely sharp. This is a modern example of the well known and fairly old double Gauss meniscus design. This design (positive, negative, negative, positive front to back) is a symetrical (or nearly so) arrangement of menicus elements about the central stop. The concept, as a photographic lens, goes all the way back to the Hypergon which was an extreme wide angle two menscus lens. One might even make the argument for the Planar of 1897 as being in the same family, but this was not a wide angle lens. This lens type, which includes the Metrogon, the Rectagon, the Cooke Series VII Wide Angle, the Kodak Wide Field Ektar and the Meyer Weitwinkel (wide angle) Anastigmat, to name just a few, several of which cover up to and over 100 degrees, are charactorized by very flat fields and low astigmatism. The draw back with this lens was always the oblique spherical aberration at wide apertures in the older examples. This is cured by the user by simply stopping down, whereupon it goes away. What's left is a very good optic with good field flatness. Your lens is a modern, coated lens, and its a good thing, because the other big problem with this type is the absolute necessity for the lens to be coated, since it has eight air-to-glass surfaces. This renders older, uncoated examples nearly useless, in my opinion. This very reason is the fact that facilitated the perpetuation of other types of wide angle lenses that did not have such flat fields, such as the little Protar Series V.

>Dear Ron,

I am slowly coming to grips with my Wisner 8 x 20 back. I thought the move from 8 x 10 upwards would be fairly easy, but there is a surprising amount of detail and technique to re-learn at 8 x 20.

Lens coverages:

I thought I would let you know that the 355 f9 G-Claron DOES cover 8 x 20, and is a realy nice lens for the format. It is sharp right to the edges. However, it really does need a centre filter. Developing negs to N contrast for silver printing does not show up any significant density differences between centre and edges. However, develop the neg to N+2 for Pt/Pd and the light fall off is so significant as to ruin the neg.

The Nikkor 450M f9 also covers 8 x 20, however it is nowhere near as sharp at the edges as the G Claron. It really needs stopping down to to f 64 or smaller to get anything half decent.

The 600 f11.5 Apo Germinar also covers the format easily.

Hope you find this of interest, please pass it on to other large format users.

Is anyone interested in gettng together a Kodak order for 8 x 20 TRI-X ???

Regards,

Rob Nayler, Herefordshire, England <

Dear Dr. Nayler,

Thank you for your comments. I will indeed place them on the web for the benefit of our readers. I am not at all surprised at your comments regarding the 450m Nikor, since this is a Tessar type lens and as such would experience significant astigmatism and some lateral color as it approaches about 60 degrees, which is about what this combination represents.

> Ron,

The Symmar-S 135mm is my usual first choice with 4x5, and I'm looking for a lens with similar characteristics when I step up to 8x10. Since I read your comments that the G-Claron's image angle is closer to 80 degrees than the 64 degree specification Schneider lists, I've been considering the 270mm as my first choice for the larger format. Is there a formula I can use for calulating the useful image circle of this lens? Are there other lenses of the same focal length I should be considering?

Thanks,

Dear Mr. Phillips,

There are indeed formulas for calculating the image circle of any lens. If you know the angle of view (opticians sometimes call this the "image height"), then you can use a little trigonometry to figure the resulting relationship with any focal length and format. Rather than subject everyone to a tedious mathematics excerise, I offer herewith a table which I calculated for all common focal lengths and formats. Just use it as a look up table. Find the format across the top, then match it to the focal length on the left. The number where they meet is the angle in degrees that would result. If you know the angle of view of the lens as per published specs, you will then know if the lens will cover that condition.

As for other similar performing lenses, I certainly would consider any Dagor type lens in that range.

Dear Ron,

Do you have a favorite way of finding the bellows factor?

My 210 mm does not give me too much trouble, but the 300 mm at close range is more critical. I have been using an expensive method. I shoot tons of Polaroid. That way, when it looks good on the Polaroid, I start using the real film. I have been putting off doing a test for some time. My idea was to make a large tape strip and tape it to the monorail. Then, I was going to calibrated it with marks at 1/4 f stops. Is there a formula for the bellows factor? I used to know one years ago. Do you have an easier way? Tony <

Dear Tony,

My preferred method is to calculate the new f:stop. This makes more sense to me because it recognizes two things: first, that the focal length of a lens is only the engraved or "nominal" focal length at infinity, and second, that if the effective focus changes when one is not focused at infinity, so does the f:stop.

Simply put, the diameter of the aperture opening is divided into the focal length, and however many times it will fit gives you the f-number. Using whole numbers which are easy to use in your head, if a lens focuses at ten inches at infinity, and the opening is one inch in diameter, the lens is functioning at f:10. If you focus at some closer distance, so that the effective focal length is 11 inches, then the lens is now functioning at an effective stop of f:11 (one inch goes into eleven inches eleven times, right?).

So transferring this technique to any lens, first simply find the lens opening, then you can do any calculations from it very easily. In the above case, I gave you an arbitrary one inch diameter. If you have a lens for which you would like to know the opening for any given stop, just divide the f:number into the nominal, or engraved focal length. Then use that number divided into the new bellows length fo find the new f:number value.

> I am new to large format and was wondering if you could explain why smaller aperture settings are preferred on the bigger formats?

In 35mm photography it is common to see lenses that have f4.5 to f5.6 and extend up to 22, but with your convertible lenses they will already be stopped down to 9.x and 13.x. What happened? Since they are built to specs designed by you, you could have chose any maximum aperture you wanted, but still chose these smaller diameters. There is a part of me that says "Who turned out the lights?", and mentally I discount the lenses because they don't have the bigger openings that I am accustomed to. Is there a shift in optic properties equivalent to increased focal length that I missed somewhere? Or are you assuming that in larger format people will be keeping the lens open for longer periods of time due to the availability of a tripod?

Thanks for your advice, and I am pleased to see an organization such as yours that still values pride in craftsmanship.

Steve Tinkle<

Dear Mr. Tinkle,

The practice in large format is indeed to use smaller stops than with miniature cameras. The bigger the camera, the smaller the stop. This is for a variety of reasons, including depth of field and the convention that in large format work everything is normally supposed to be in focus, and the fact that large cameras and the focal lengths they use have to be stopped down to get the depth of field required. Then there is the issue of size, weight and cost. An f:4 lens would have to have an opening of about three inches,and would have to have a front glass element of close to four inches to be usable without vignetting. This gets both heavy and expensive. Since the ultimate stop used for the photograph is rarely less than f:16, the additional expense and bulk of such a lens is not deemed advantageous.

Dear Ron,

I have been shooting on 5 x 7 for some time. I had no film on hand and was forced to shoot small format (4x5). I now want a 210 mm 5.6 to use on the 4x5. I saw two for sale locally. One is a f 5.6 210 mm Nikon. The other is the same in a Caltar II, but a lot cheaper. Would I see any difference at f 11? I shoot only people portraits.

Also, I am thinking of replacing my big 300 mm Kodak f 4.5 in a #5 Ilex. How would the Nikon 300 mm f 9 compare? I am told that both are Tessar designs.

Thanks, Tony <

Dear Tony,

I know that some of the earlier Caltars were tessar type lenses, but I was not absolutely sure of the designations so I checked with Calumet. The later Caltars would be either S or N types, signifying Symmar, made by Schneider, or Sironar, made by Rodenstock. Without the S or N, and if the lens is mounted in an Ilex shutter, the lens is probably a tessar type. As such, the lens would probably not perform as well at f:11 as the other two, which are later plasmat type lenses, or the Nikon which is also a later plasmat type. This would account for the difference in price. By the time any of the above lenses reach f:22, however, they would be very hard to tell apart in as far as sharpness is concerned. Contrast would even be close since the Caltar (presumably a tessar type) has fewer air-to-glass surfaces.

Replacing the Kodak tessar-type lens with the NikonM, also a tessar, would be a very good idea in my opinion. They are both sharp lenses, but the Nikon is probably sharper. I have noted that over the past century the tessar, or really Tessar, since it was once the proper name for Zeiss' trademarked, patented lens, has gotten better in the hands of every successive generation. Most of this can be attributed to the better and better glass available to the designers over the years (the mathematics hasn't changed). So the tessar-type design has not only been a very viable design concept, but the examples from one generation to the next keep getting better. Kodak, for instance, greatly improved the tessar-type when they reversed the rear doublet and used some of the rare-earth glass available in the '50s. The Apo-Lanthar is another example of taking the basic design and making it better (though it does not really deserve the cult statis it now receives).

Just remember the tessar-type only covers about 60 degrees. But as a long lens-to-format optic, a low aperture tessar-type (or artar-type) is a great way to lighten the load without sacrificing sharpness.

Update: 7/12/99

Just to clarify, when I use the term low aperture, this means a slower lens such as the Nikon f:9 example mentinioned above. High aperture, then, would be a faster, wider lens. In large format these are typically f: 5.6 or wider.

> Dear Sirs:

I have been very seriously considering moving into the 4X10 format and have a couple of questions. The first is a technical one regarding a lens and the other has to do with configuring one of your cameras for this type of work.

I have read more than one reference to using the Schneider 90mm XL lens with the 4X10 format. In particular, Jay Dussard talks about using that lens for a number of the images in his "Open Country" book. I have to admit to being somewhat confused though about how that lens covers that format. I calculate the diagonal for a 4X10 sheet of film to be 273mm and the image circle for the lens is listed as 259mm. Even if I allow a 1/4 inch border on the film for the holder I still get a diagonal of 265mm. So it would seem to me that the lens comes up short on coverage. Am I missing something here or is the published specification on the image circle possibly a conservative number? Any light that you can shed on this for me would be greatly appreciated.

My other question concerns configuring one of your cameras for both 4X10 and 8X10 work. Would this be possible and if so what would be involved? I would also like to know if it is possible to do vertical as well as horizontal compositions with each format. It seems that this should all be possible but I have not been able to determine if your designs allow for these configurations. I would really like to have as many options open to me as I move up to this format.

Thank you in advance for any advice and input you can offer me.

Take Care

Bob Dart Plano, Texas<

Dear Mr. Dart,

About the 90mm XL, I think your assumptions are correct. I believe the lens is supposed to cover about 110 degrees. If you do the math, 90mm on a 4x10, less the borders of the film comes to 111.1 degees at infinity. The hair splitting of using the decimal is silly, of course. But virtually all specs are quoted at f:22, and you can expect a little increase in coverage when you stop down. Furthermore, I agree with you about the conservative numbers. This seems to be the habit at Schneider.

As for your question about the formats, honestly, you have just made my case for carrying my 8x10. I do indeed shoot both 4x10 and 8x10, but I am not at all rigid at keeping to the strict 4x10 format. I will make what ever shape format suits the subject. Sometimes that will be 4x10,sometimes 6x10, and sometimes some other non-descript size, such as 7x9. I definitely am not one of those purists to whom printing the exact format is some kind of virtue, as though not using the exact borders of the format in question makes you less of a photographer. I am especially annoyed at the effete practice of printing the goo around the edges of a Polaroid negative, which I regard as an affectation. Shooting 8x10 to make from 4x10 up to 8x10 negatives, both vertical and horizontal, is exaclty why I have chosen 8x10 as my camera of choice.

I just purchased a Korona 7x17 camera, and had a question about ground glass/film plain accuracy. What is the likelihood that this camera was a plate camera? If so, what thickness should the shims be to make spacing accurate for film? Also, can I assume that your 7x17 film holders will fit my Korona? (At this point, I'm trying not to assume anything...)

Thank you for you help,

Ben Lineberry

Dear Mr. Lineberry,

We actually have all of the measurements for your Korona, but even so we always like to measure the back of an old camera in case of changes which might have been made over the years. We have discovered many discrepancies and find this bit of insurance worth while.

Update 6/25/99

After re-reading my answer to Mr. Lineberry, I realized I did not really answer his question. Must have been in a hurry that day! Many old cameras are indeed glass plate holders. The older they are, the more likely they were designed for glass holders. In conferring with my data and that of Alan Brubaker (a maker of very fine holders), it is clear that one cannot be sure of the specific measurements of one or the other. It is clear that there was some attempt on the part of some manufactureres to use the same "t" demension (film registration) in order to make the conversion from glass to sheet film "seemless", but one cannot count on this. The best thing is to check with your manufacturer and obtain the data so as to compare it with any extant holder or camera you may be considering using.

I have enjouyed reading your Q&A section, and hope that you will have the answer to my question as you have with so many others. I am considering buying a 180mm lens for my 4x5, and do not know wheather or not it is worth purchasing a Schneider APO symmar, instead of a Symmar S. I know that apochromatic correction gives a gain in sharpness, but how much? I will be using the lens for both lanscape and portrait work, in color and black and white, and shoot wide open a fair portion of the time. However, I do not plan to enlarge beyond 20x24. Please enlighten me as to the nature of these two lenses, and what you believe would be best for my application. Your summary of "flat field" lenses was astoundingly educational and clear, and I look foreward to your reply.

Sincerely,

Jason B. Brownrigg<

Dear Mr. Brownrigg,

This is a great question, because alot of people probably do not know what the real issues are here. Ten or fifteen years ago when the buzz word "apo" got attached to virtually every new lens on the market, it did seem to me that it was a marketing gimick. As it turns out, the answer is yes and no.

The "yes" comes from the following fact: in normal acromatic correction one can expect colors to be corrected to within more than one-one-thousandth of focal length. This means one tenth of a millimeter for a 100mm lens. In other words, if red and blue come to sharp focus at 100mm, green will be out of focus by about .1mm. Specific wave lengths at certain emissin lines are used to set these standards, but it is not necessary to go into that here. I will digress for a moment by saying that there has been a gradual shift toward longer wave-length emission lines by which to judge how a lens meets both achromatic and apochromatic correction standards. This is because of the gradual shift of film to the longer part of the spectrum since the beginning of the century.

The above mentioned level of correction amounts to "defocus" between the colors. Essentially, there will result a circle of confusion for which ever wavelengths fall outside the image plane. As you probably can see, a circle of confusion resulting from being out of fucus only one tenth of a millimeter is hardly worth worrying about. Such can be easily accommodated by depth of field and stopping down isn't even necessary.

But what about really long lenses? A 355mm for instance. And suppose you need to shoot wide open? This means a defocus of .35mm. The problem gets a little worse at the edge of the film because of the slightly different sized images of the offending color. Granted, this is extreme. I cannot remember when I last shot a normal focal length large format lens wide open. The real benefit comes when you are talking about very long lenses. A 600 whose chromatic defocus is close to a full milimeter might be a problem. I have indeed shot a 600 wide open off the top of a mountain at sunset when I was shooting water. The subject required no depth of field but I did have to stop movement. The big 35mm super tele lenses such as are used to shoot football games are the ones which benefit most from apochromatic correction, which correction is on the order of about one-twenty-four-hundredth of focual length.

So, do you need an apochromatic lens? Maybe, maybe not. One benefit of the newer Apo Symmar is the fact that the lens is more symmetrical than the former Symmar S. The powers of the lens-halves are more equally balanced. The benefit is the improved performace at a wider range of magnification ranges, even up to 1:1. Not all apo lenses are desinged the same way. The Nikon M lenses are Tessar types, and since they are not symmetrical I would not be tempted to use them at 1:1. They are designed for inifinity. They are, however, rather long (up to 600mm), and they do benefit from apochromatic correction.

First, thanks for getting my camera fixed so quickly. The tourist that kicked my tripod leg causing my Technical Field to take a tumble will be marked and identified for future reference.

I have been trying to reduce the weight of my pack and I need your help. I have recently replaced my Schneider Symmar 90 F8 with a Schneider 90mm f68, which is 1/5 the size and weight. While the shutter speeds are "old style" I love the sharpness and ease of use this lens provides. Can you recommend other lenses to replace these?

Schneider Super Angulon 210 F5.6 Schneider SA 120 F5.6 Schneider 305 F9 G-Claron

Thanks.

Mitchell Russo <

Dear Mitch,

I see you have joined the ranks of the converted. I have been preaching for years the benefits of the smaller, older type lenses. Not to say that the modern lenses are not wonderful, because they are. The modern lenses come into their own especially in wide angle photography, since modern wide angle lenses are clearly superior to older ones. But for landscape photography, I have always felt that "getting there" was more important, and extreme movements are not generally necessary.

As for my suggestions, they are as follows:

Schneider Super Angulon 210 F5.6: Replace with almost anything!!! This is a huge lens. Dagor, G-Claron, Protar, or the Scheider Angulon.

Schneider SA 120 F5.6: Great for architecture, overkill for landscape. I would keep it but get a Dagor, Schneider Anglulon or perhaps a Wide Field Ektar 135mm

Schneider 305 F9 G-Claron: Honestly, this one is a keeper. It's small, light and has 80 degrees of coverage. If you really want to go lighter, you could consider the NikonM 305 or an Artar. they are both smaller and have about the same aperture. They don't cover as well, however. The Nikon only covers about 60 degrees, and the Artar covers less than 50 degrees.

Update: 6/16/99 When I first answered Mr. Russo's question I failed to noticed that his 210mm was an f:5.6. Therefore it cannot be a Super Angulon, which is an f:8 lens. My response may be a little extreme in this case, since only the Super Angulon is really giant. Even so, for Mr. Russo's purposes there can be some savings in weight and size by switching to a G-Claron which is an f:9 lens, or the above mentioned Angulon, the old f:8 dagor type.

One year ago, I bought ancoated Wollensak Velostigmat wide angle Series III f9.5 -8x10 on a Betax #3 shutter. Focal length between 165 to 170mm as measured on my 4x5 TF. Is this a double Gauss four elements single meniscus design? (Topogon,! Metrogon, Homocentric; etc). What is the difference between this objective and the Wollensak f12.5 extreme wide angle? I really enjoy the 4x5 Wisner TF and your large format Q&A board. Thank you for your time. Tito Sobrinho. <

Dear Mr. Sobrinho,

Yes, you are correct about the Wollensak. The difference is that there is an additional element buried in each half of the lens, in other words one of the menisci is actually a cemented doublete. Can't at this moment remember which one. The lens should have slighlty better correction, probably color. I have never actually tested this one against the f: 12.5 for comparison to see how much and in what specific way the corrections are improved. The problem with your lens, as with all uncoated gauss type lenses, is the excessive flair. Unfortunately the very thing which might have made the lens more desirable is the very thing which makes it un-fixable. The lens should be coated, but the only way to do so is to take it apart so that the air-to-glass surfaces can be subjected to the heat of the coating process. There is simply too much labor involved in taking your lens apart because of the cemented surfaces to make such a proceedure worth while.

I'd really like to hear your opinion on why no retrofocus WA lenses are available. Telephoto LF lenses exist because some field cameras do not have enough bellows extension. Given the following difficulties with conventional WA lenses:

1. Bag bellows necessary for many cameras. Impossible for some cameras. 2. Little movements because the two standards are so close and small image circle. 3. Difficulty in focusing and evaluating the whole image on the ground glass because of light fall off.

Why doesn't anyone make an inverted telephoto lens (retrofocus WA lens)? I see more reason and a greater market for a retrofocus WA lens than a telephoto long focal length lens. Wouldn't architectural photographers just snatch up a 65 mm WA that works at 150 mm bellows extension when focused at infinity with the image circle of a typical 4x5 normal lens without the need the center filters?

Low distortion and good MTF might be hard to achieve, but the Canon 24TS achieves both and is a retrofocus design. Perhaps floating elements are necessary? I don't know. What do you think, Ron? Thanks.

Carlos Co<

Carlos,

Retro focus lenses, which, as you point out, are essentially reversed tele lenses, have the same objectionable problem that tele lenses do. Such lenses have the unique property of having greater focal distance than the image size and angle of view would indicate. Because the essence of such lenses is to displace the node, or exit pupil of the lens to a place which provides some particular advantage, this by its very nature makes the lens difficult to use with front camera movements. In both cases, the node is no longer anywhere near the axis of the front standard. In the case of tele lenses, the node is way out in front of the camera, which allows the camera to use shorter bellows. In the case of a retro focus lens, the node is behind the lens and front standard.

In both cases, when a tilt is used, the node swings wildly and the image moves on the ground glass in a magnitude which is completely objectionable. The real advantage to the the retro focus lens is to simply allow clearance for the reflex mirror of such cameras. Also in both cases, the design is cleaner and better if the image is not being reduced or enlarged by a secondary lens, as is the case with both types.

I will say that, compared to earlier Dagor or Protar type wide angle lenses, modern "Biogon" type lenses such as the Super Angulon and Grandagon do benefit from some small degree of increased distance to the ground glass, compared to thier actual focal length. A 90mm lens typically will have a flange focus of about 100mm, or about a 10% increase in flange distance. The reason is simply the longer optical system of these large designs.

Tony<

Dear Tony,

I would have no problem using wooden holders such as you describe. Wood has several advantages: they are lighter, they can actually be more accurately focused since wooden holders are machined, not molded and they work more smoothly with wooden cameras. I actually use wooden and plastic holders all the time without regard or concern.

I am considering the acqusition of a Wisner 8X10 whose negatives would be only contact printed with a piece of glass over them . The problem are the famous Newton rings . I s there a way to avoid them?

Many Thanks Antonio Collares

Dear Mr. Chaves,

Newton's rings come from the interferometric destruction of light reflecting between two surfaces in close contact. The colors come from the fact that the airspace varies minutely and thus causes destruction of certain wavelengths selectively. The old way to solve the problem was to use non-reflective glass which had a texture. You have probably seen this same stuff on framed photographs. I think it is horrible stuff, and one day I should comment on the proper method of framing and lighting photographs. But I digress. A much better solution to Newton's rings is to use glass coated with antireflective coatings. I use a piece of multi coated glass to make my contact prints. Multi coating reduces reflections .5% from the 4% of uncoated glass, or a factor of 8. Thus, any Newtons rings which still exist are nearly invisible.

Message text written by "Clyde R. Shappee"

>Ron,

I know that you use the Polaroid type 55 in your workshops, so I am curious, what ISO rating do you recommend for the Print only, for the Negative only, and if one might wish both.

Clyde R. Shappee

Dear Mr. Shappee,

I have been aware for years of the admonition to use a lower ASA for the negative than for the print. I must admit that I have always used about 50asa, regardless. The resulting negatives have produced some wonderful images up to 20 by 30 inches, some of which hang in our lobby. Most of you know that exposing the film an extra stop is no crime, however, since it merely raises the exposure higher up on the curve, thus giving better shadow separation. Polaroid type 55 is fabulous film in every respect and can be used to make very fine images. It has a wonderful scale and very fine grain. A well exposed instant print has a gray scale that is hard to beat.

>Dear Sir, I have acquired a Seneca 8x10 view camera. It came with two Seneca holders, each capable of holding two glass plates. My question has not been answered by the two camera shops that I have asked and I feel confident that you will know the answer. I realize that a Seneca is not the quality of a Wisner, but this is a general question that only a large format guru would know the answer to. My question is ... If I purchase new 8x10 "film" holders for use with this camera that originally used plates, will the ground glass need to be moved fore or aft in the camera back (by recessing it into the back further or adding shims, respectively) or are this taken into account when the holders and manufactured? In other words, will an in-focus image on the ground glass provide an in focus image on the sheet film in a modern holder? Thank you for your time, David <

I have several cameras in my collection which were originally used with glass plates. One can suspect any turn of the century view camera as having been glass plate cameras. In general, glass plate registration is closer to the front surface of the holder than sheet film, and you will have to increase the spacing of the ground glass frame by gluing a shim to the front of said frame. I have done this to two of my cameras so that they may use modern film holders. Interestingly enough, our grandfathers were faced with a similar problem, because glass plates and sheet film coexisted. There were adapters which were made to convert glass plates holders to sheet holders, and the use of these adapters with glass plate holders obviated the need to convert the camera.

My specific application is tabletop biologic specimens. I'm using 4x5. The magnification ratios will vary between 1:3 and 1:1. I have a 150mm Schneider "apo" Componon HM which I could use, or should I get a modern 120mm macro, such as a Sironar, Symmar or Nikkor? Does a "flat field" have any advantage? (I had a chance to get a 100mm 6.3 Zeiss Luminar but didn't know enough about the lens).

According to Schneider the Apo Componon HM 150mm was really designed for very large enlargements up to 12x. Even if this were not the case, I think the shorter 120mm macro Symmar would be better, since you will be using alot of bellows in macro shots. The Symmar is a 1:4 to 4:1 lens, optimized at 1:1. If by "flat field" you refer to a G-Claron, Artar, or other such process type lens, they all would be fine for your purpose.

As far as the "flat field" issue is concerned, this is actually one of my pet peeves. In my opinion, there is no such thing as a "flat field" lens. All lenses are designed to render as flat an image-field as possible, by definition. After all, film is flat. This is a meaningless, non-technical term perpetrated by marketers to differentiate so-called "normal" lenses from those which are ostensibly for copy work. This is probably the origin of this erroneous term, since most copy work involves flat art. It is often claimed by these same persons that the so-called symmetrical lenses designed for 1:1 are somehow not good for anything but 1:1, to the exclusion of infinity work. I would simply point out that most large format lenses in the early part of this century were symmetrical. Lenses such as the Dagor are absolutely symmetrical and were made right up to the 1980s by such esteemed firms as Schneider. No one would ever suggest that these could not be used for virtually all large format work, at any distance.

I have heard that the G-Claron 210 and 240 cover 8x10 at infinity, despite Schneiders specifications. Do you recommend these lenses for 8x10 at infinity? Do they cover? <

The G-Claron apparently is a greatly misunderstood lens. Though the "official" Schneider specs state that it only covers 64 degrees at f:22, this is very understated. Both the 210mm and the 240mm will indeed cover 8x10. The G-Claron will actually cover up to 80 degrees at f:45, so they are very much like thier older and very close relative, the Dagor in that they are symmetrical, thier coverage increases as you stop down (like all good vintage lenses), and they are usable at any magnification ratio.

Want More Information on the above topic: use of small, light-weight symmetrical lenses? See the new page of down-loadable articles.

I am curious about some issues concerning 16x20 camera's and film. I am planning on building a 16x20 camera and am curious as to how much you charge for a 16x20 holder. also, concerning issues of film flatness, is that a problem at 16x20, or do you have a remedy within your holders.

I am well aware that this is no small project, and so am not chomping at the bit for answers, but am wondering about some of the logistics before i begin this endeavor. any comments would be most appreciated.

Also, the golden gate images are wonderful! and to think people thought i was crazy for some of my 8x10 excursions.

All best, scott

The issue of film flatness is not as serious as many might think. Because the working apertures of large cameras are so small, we are usually dealing with rather high depth of field. I wrote an article for Darkroom Techniques (now Photo Techniques) several years ago, in which I did an analysis of circle of confusion resulting from "defocus" vs aperture controlled diffraction and found that with long lenses, and apertures of f:45 (tyipical) or smaller, the defocus from film unflatness can be as much as .030" without much obvious effect.

Some solutions are a vacuum back or adhesives on the septum. With my experience shooting our 20x24, I have not found either necessary.

Arthur Nichols

At this point in my photographic journey (about 30 years) I would like to do special B&W portraits and feel deep inside something telling me to use a 8x10 field camera. Medium format camera results are good but they lack something magical that I only see in large format cameras. I like the idea of doing contact printing and maybe some Polaroid prints, and on rare occasion enlargements from the 8x10 negatives. Again 8x10 contact prints are magical to me.

I have searched around and found your camera company to be the best so far. Plus I liked your articles that you wrote. But which 8x10 camera and lenses is the best for portraiture work and maybe some landscapes on the side given the 8x10 print size? I know the most expensive models will do everything, but feel that it might be a case of overkill, same with high end lenses.

Thanks for the good advice that I know you will give,

Don

It would be hard for me not to be biased in favor of 8x10, since that is the format I most use. I certianly agree that there is something magical about a contact print, and the 8x10 is ideal for a variety of reasons, one of which is that its diagonal is roughly equivalent to normal reading distance, so they are particularly well suited to hand held viewing.

For a number of reasons related to optical transfer function, contact prints will generally be appear sharper than prints from small negatives, but the "look" has more to do with tonal fidelity than actual sharpness.

As far as lenses are concerned, the choice will depend on your ultimate purpose. Do you want sharp, "charactor" images, or more flatering soft focus images. I favor the former. Dagors, G-clarons, Artars, and other such symetrical lenses will do the job. If you want something a little softer, one of the old Cooke triplets or a Rodenstock Imagon might be better. I use a set of Protars, a "Dagor" type lens. I would go with something long, at least 355 or more is you want to use it for Portraits and landscapes.

The camera would probably be the 8x10 Traditional because you do not seem to need all of the bells and whistles of the other models. The Traditional will still handle anything you want to tackle, even architecture, just not quite as easily as models with more movements.