IQ of digitar lenses on 6x7 film back versus film lenses

[Weihan]

Has anyone ever compared the IQ of shots taken with a view camera + a 6x7 / 6x9 FILM back using a Schneider or Rodenstock digital lens versus a 4x5 film image shot with a traditional analog lens? I'd be interested in seeing the results or in reading about the assessment of the differences. I'm sure the digital lens will have a much higher resolution on the film, but does this result in an overall better IQ when compared to the overall better tonality of a 4x5 image? I imagine film flatness might play a significant role. Please note: I'm not interested in the result of a digital image on a digital back but rather solely in the film results. THANKS!

[paulr]

I haven't. We can assume the lenses are in a whole other category of sharpness and resolution ... you just have to compare the same manufacturer's MTF curves between the product lines. It should make a big difference at big enlargements, if you can manage focus accuracy, etc. etc..

But!! I don't know if any of these lenses will even cover 6x7. Many of them won't. It's a big butt.

[Bob Salomon]

I haven't. We can assume the lenses are in a whole other category of sharpness and resolution ... you just have to compare the same manufacturer's MTF curves between the product lines. It should make a big difference at big enlargements, if you can manage focus accuracy, etc. etc..

But!! I don't know if any of these lenses will even cover 6x7. Many of them won't. It's a big butt.

Most of the Rodenstock ones have image circles of 120 to 150mm so they will cover most roll formats with no problem.
But be aware, The Rodenstock HR Digaron-S series and the former Rodenstock Apo Sironar Digital HR lenses require a correction plate mounted to the rear of the lens if these lenses are used with film. This is because the last element in the formula of these lenses is the cover glass over the sensor on digital backs. If the corrector plate is not used then the image will be slightly out of focus on film.

The Rodenstock HR Digaron-W and the Rodenstock Apo Sironar Digital and the Apo Macro Sironar Digital lenses do not need a corrector plate for use with film.

The new Rodenstock 90mm HR Digaron SW will probably not require a corrector plate and one has not been announced yet. This lens replaced the 90mm HR Digaron-W which is no longer manufactured.

[Weihan]

This is very helpful info. Do you know if there is any feedback on the IQ from users who've actually employed the lenses with rollfilm backs and how the IQ might compare with 4x5 film + analog lens? Schneider also offers the Schneider 120mm f/5.6 Apo Digitar N Lens w/ Copal #0 Shutter with a state 120mm i.c. that will cover up to 6x9 if I'm not mistaken.

[Bob Salomon]

This is very helpful info. Do you know if there is any feedback on the IQ from users who've actually employed the lenses with rollfilm backs and how the IQ might compare with 4x5 film + analog lens? Schneider also offers the Schneider 120mm f/5.6 Apo Digitar N Lens w/ Copal #0 Shutter with a state 120mm i.c. that will cover up to 6x9 if I'm not mistaken.

Not really. We do know that MIT bought the HR Digaron S Rodenstock for a film project but they have never told us if they had any problems with it for this purpose. I am sure that we would have heard if they did have a problem or if it was not performing to stated specs.

Since we are the distributor for Rodenstock and not a retailer for Rodenstock (we sell them to camera stores) we do not always know what purpose the retail purchasor bought the lenses for.

[Weihan]

This sounds very exciting. Thanks a million for all the information. If you do eventually get feedback from the MIT project, it would be great to hear about it second-hand, assuming there's no breach in confidentiality.

[Weihan]

For Paulr: Some of these newer Rodenstock and Schneider digital lenses will cover up to 6x9 film (see Bob Salomon's information above), so my guess that the most critical component would be actual film flatness. One would need to do the utmost possible to achieve that, so my guess that a great deal would really depend on the quality of the rollfilm back being used.

[Oren Grad]

I have the 90mm Apo-Sironar-Digital (later relabeled HR Digaron-W). I use it with 6x9cm film. It covers 6x9 with ample room for movements. It's an excellent lens by the usual bench-test criteria, but what appeals to me especially is that it seems to draw similarly to the Apo-Sironar-S series, which is my favorite modern plasmat type for LF, even though the A-S-D has a rather different optical cross-section.

But I'm afraid I've never tested the 90 A-S-D on 6x9 in a controlled way against a comparable lens on 4x5, and I don't intend to; it's not a question that matters for my working habits. Based on experience with both 6x9 and 4x5, though, and assuming the same film for both 6x9 and 4x5 and appropriate working apertures in each case, I doubt very much that you're going to get "much higher resolution on film" with the 90 A-S-D on 6x9 compared to, say, a 135 Apo-Sironar-S on 4x5.

[Sevo]

I doubt very much that you're going to get "much higher resolution on film" with the 90 A-S-D on 6x9 compared to, say, a 135 Apo-Sironar-S on 4x5.

I agree. It may be possible to measure some improvement, but visually, the film will be the limit when downsizing from 4x5" to 6x9cm - no lens can overcome that.

[Weihan]

For Oren: Thanks for this reply. Do you have any of your images posted anywhere accessible to the general public or to users of this format? My concern is not really with resolution as such but with the overall impression of the image in comparison to 4x5. I'd love to be able to move up to 8x10 because of the unique qualities provided by the much larger format, but back problems just wouldn't allow me to carry the weight of all the extra gear required for 8x10. But I would very much like to see the results of these newer digital lenses on 6x7 or 6x9 film to compare the overall look with a 4x5. I, too, have regularly used the 135 and the 150 S-Sironar and very much like the output, but I can say the same for the results of my 90/5.6 superangulon.

[Weihan]

I agree. It may be possible to measure some improvement, but visually, the film will be the limit when downsizing from 4x5" to 6x9cm - no lens can overcome that.

I suppose I was subconsciously expecting somehow that the use of the digital lenses might magically transform the smaller film format into the same kind of improvement we get when switching from MF to LF. As I said above, I'd very much like to use an 8x10 but I couldn't carry the extra weight because of back issues. But the jump in tonality with 8x10 would be well worth the extra weight if I were able to carry it. Thanks!

[paulr]

Bob, I'm looking at my Rodenstock datasheet for Digaron S and W lenses. Have the lenses been updated? The diagonal for 6x7 is 92mm. The only lenses listed that will cover that (with minimal movements) are the 70 and 90 HR Diraraon Ws. The sheet I have is called e_Rodenstock_Digital_Lenses_3-26__8236.pdf

What does the corrector plate correct for?

[Nathan Potter]

I'm also interested in the answer to Pauls question and additionally; where exactly in the image side of the lens does the corrector need to be. In other words does it need to be located directly in front of the film as it is on most sensors or can it be close to the rear element?

Nate Potter, Austin TX.

[Oren Grad]

Do you have any of your images posted anywhere accessible to the general public or to users of this format?

I don't have anything posted from either 6x9cm or 4x5". But it's moot, because scanning and reproduction on the web would obliterate the sort of subtlety we're talking about.

It would help to know more specifically what you're trying to accomplish. What kinds of subjects do you want to photograph? What are your typical working apertures? What film(s) do you like to use? How will you print? (darkroom? scan + inkjet?) How large do you want to print?

[Dan Fromm]

Oren, wassamatta you? You're focusing on ends, not means.

[Weihan]

I don't have anything posted from either 6x9cm or 4x5". But it's moot, because scanning and reproduction on the web would obliterate the sort of subtlety we're talking about.

It would help to know more specifically what you're trying to accomplish. What kinds of subjects do you want to photograph? What are your typical working apertures? What film(s) do you like to use? How will you print? (darkroom? scan + inkjet?) How large do you want to print?

Thanks, Oren. I do landscape only and typically shoot on a Linhof Technikardan and use a range of lenses in the f22 and often smaller, primarily wide angles but also occasionally 135 and 150mm. My normal films are Velvia 100 and Extar 100. I usually get hi-res drum scans made of the best images and then print from the digital files using a Lightjet on Fujiflex, normally in the 20x30" size.
My biggest problem is a serious spine issue which means I'm very limited in the amount I can carry. I've also used both Rollei and Hasselblad systems, but of course I prefer the "look" of the 4x5s. I've also used a Mamiya 7 for a number of projects but in general I don't care so much for the look of the Mamiya lenses for some reason and the range finder apparatus just isn't the same as focusing off the GG. As I mentioned, I'd ideally like to shoot on 8x10, but my spine problems prohibit carrying so much weight. Even the 4x5 with film holders, lenses etc. tend to cause pain, so I'm really limited in what I can do physically. A rollfilm back of the 6x9 range might do it, but if there's a noticeable downgrade in image quality, I'll just continue to use the 4x5. I'd thought that maybe the digital lenses on a 6x9 film back might produce similar results to the 4x5.

[EdSawyer]

The corrector plate would generally just be a flat piece of glass I'd think, same as a sensor cover in thickness. The purpose would be to shift the image back very slightly, most likely. With ground glass and bellows focusing though I'd wonder if it is needed? It is not like the lens has a rigid flange-film distance, given a bellows is in there...

[Oren Grad]

Thanks, Oren. I do landscape only and typically shoot on a Linhof Technikardan and use a range of lenses in the f22 and often smaller, primarily wide angles but also occasionally 135 and 150mm. My normal films are Velvia 100 and Extar 100. I usually get hi-res drum scans made of the best images and then print from the digital files using a Lightjet on Fujiflex, normally in the 20x30" size.
My biggest problem is a serious spine issue which means I'm very limited in the amount I can carry. I've also used both Rollei and Hasselblad systems, but of course I prefer the "look" of the 4x5s. I've also used a Mamiya 7 for a number of projects but in general I don't care so much for the look of the Mamiya lenses for some reason and the range finder apparatus just isn't the same as focusing off the GG. As I mentioned, I'd ideally like to shoot on 8x10, but my spine problems prohibit carrying so much weight. Even the 4x5 with film holders, lenses etc. tend to cause pain, so I'm really limited in what I can do physically. A rollfilm back of the 6x9 range might do it, but if there's a noticeable downgrade in image quality, I'll just continue to use the 4x5. I'd thought that maybe the digital lenses on a 6x9 film back might produce similar results to the 4x5.

Thanks, Weihan - that's very helpful. A few thoughts:

If you're stopping down to f/22 and beyond - or, say, f/16 and beyond on rollfilm - the "digital" lenses are going to perform just like good non-"digital" view camera lenses. To the extent that they achieve new standards for resolution, it's because they're optimized for wider apertures than are customarily used for film in view camera applications. Stop down, and diffraction will remove any theoretical advantage.

As it happens, I don't like the Mamiya 7 lenses myself - I think their OOF rendering can be pretty nasty in many situations. But between inherent optical performance and film flatness, they probably do as well or better in terms of on-film acuity in practical use than you'll get from even very nice view camera lenses used with a rollholder. And FWIW, the rollholders that are arguably best - the Linhof Super Rollex for the precision and robustness of its construction, the Sinar rollholders for their flat film path - are heavy and, in the case of the Sinars, very bulky.

The only really lightweight alternative with state-of-the-art glass that comes to mind for 6x7 is the Fuji/Cosina twins - the GF670/Bessa III folder with 80mm lens and the GF670W/Bessa IIIW with 55mm lens. I've used the GF670, and its lens is in the same league as the Mamiya 7 glass. But it does draw somewhat differently, and possibly its flavor might be more to your taste. Again, though, those are rangefinders - no GG - and only those two focal lengths are available. The other way to get a GG, of course, is with a 6x7 SLR, but that gets heavy if you're piling on the lenses.

But anyway, getting back to your underlying question: given your intended usage, I doubt very much that you'd do even as well as 4x5, let alone better, by using "digital" lenses on 6x7 or 6x9 roll film instead.

[Brian C. Miller]

I suppose I was subconsciously expecting somehow that the use of the digital lenses might magically transform the smaller film format into the same kind of improvement we get when switching from MF to LF. As I said above, I'd very much like to use an 8x10 but I couldn't carry the extra weight because of back issues. But the jump in tonality with 8x10 would be well worth the extra weight if I were able to carry it. Thanks!

Um, we just had a discussion similar to this in the Lounge, LF or 35mm (http://www.largeformatphotography.info/forum/showthread.php?99821-LF-or-35mm). Whether or not MF can equal 8x10 is really your personal call, for your criteria. When Spur (http://www.spur-photo.com/) came out with the Orthopan-UR film, they hailed it as making 35mm photography indistinguishable from 4x5. They had comparison pictures on their website. And believe me, that film comes close. But still, even on the web, the differences were distinguishable, and in all the little areas that LF photographers look at in a print. Tim Parkins' tests showed that the Mamiya 7 comes close to a 4x5. But is that "close" good enough? Only you can say for yourself.

What it comes down to is this: size matters. But lots of great photographs have been made with MF, and film like Spur wasn't used. Test the film for yourself, and make the decisions. Instead of Mamiya lenses, maybe a Rollei would be good for you.

As for packing 8x10, you might consider what I do: park, drop the tailgate, and pull out the camera. I've lived with a bad back all my life, and I've found that weight-wise, there's not much difference between MF and 4x5, and I use a Pentax 6x7 and Toyo 45AX and a Super Graphic. But the step up to 8x10 is big, and there's very few of them that are both cheap and light.

[gary mulder]

I wonder if you will be able to get a 6 x 7 film and digaron kit that weighs significant less then a 4 x 5 kit. Digaron's are heavy and bulky pieces of optics.

[Bob Salomon]

I'm also interested in the answer to Pauls question and additionally; where exactly in the image side of the lens does the corrector need to be. In other words does it need to be located directly in front of the film as it is on most sensors or can it be close to the rear element?

Nate Potter, Austin TX.

It screws into the rear of the lens.

[Weihan]

But anyway, getting back to your underlying question: given your intended usage, I doubt very much that you'd do even as well as 4x5, let alone better, by using "digital" lenses on 6x7 or 6x9 roll film instead.[/QUOTE]

Yes, Oren, I'm slowly coming to the same conclusion. It's too bad the Philips Explorer camera went out of production. Ideally, someone should take the improvements represented in that 8x10 model, which incorporated if I remember correctly, lots of newer, stronger, and much lighter materials, and bring out a new series of 8x10s that can be carried without the danger of rupturing a disc or something horrible like that. The Philips 8x10 was even lighter than my current Technikardan 4x5. You'd think with all the new advances in material science that someone would be able to come up with a good solution that doesn't cost more than a 6-series BMW.
I am going to check out the new Fuji you're referring to. I called B&H a while back to ask about the wide angle version (better suited to landscape), but they said that only the Bessa III was available in the US with the w.a. The camera does look very promising, and I think I would like the overall look of the images better than I do the Mamiya 7's. Still, for landscape, nothing beats 4x5 (except of course the untotable 8x10s).

[Oren Grad]

Yes, Oren, I'm slowly coming to the same conclusion. It's too bad the Philips Explorer camera went out of production. Ideally, someone should take the improvements represented in that 8x10 model, which incorporated if I remember correctly, lots of newer, stronger, and much lighter materials, and bring out a new series of 8x10s that can be carried without the danger of rupturing a disc or something horrible like that. The Philips 8x10 was even lighter than my current Technikardan 4x5. You'd think with all the new advances in material science that someone would be able to come up with a good solution that doesn't cost more than a 6-series BMW.

FWIW, Richard Ritter makes an 8x10 with weight specified at 6.4 lb, which is in the same ballpark as the Explorer.

http://www.lg4mat.net/LFcamera.html

Regardless, I'm sorry about your predicament and wish you best of luck in finding solutions that are workable for you and let you achieve results that you'll find satisfying!

[Weihan]

FWIW, Richard Ritter makes an 8x10 with weight specified at 6.4 lb, which is in the same ballpark as the Explorer.

http://www.lg4mat.net/LFcamera.html

Regardless, I'm sorry about your predicament and wish you best of luck in finding solutions that are workable for you and let you achieve results that you'll find satisfying!

Thank you very much, Oren! And I greatly appreciate the link to the Ritter 8x10, which I knew nothing about. That 8x10 is even lighter than my Linhof TK, so I'm definitely going to be exploring this option. Thanks so much again :)

[Noah A]

That Ritter 8x10 may be lighter than your Technikardan, but the film holders and lenses will be significantly larger and heavier than the ones you use for 4x5.

As much as I love my TK45s, it's not the lightest 4x5 camera out there and it may be overkill for landscape work. Maybe something like a Canham dlc or a wooden folder would lighten the load?

[Jim Andrada]

I was just going to suggest something like my original Seneca View - I have it on a small-ish Ries Tripod and the combination is lighter than my Mamiya RB67 on carbon fiber 'pod with a 3 way head.
I use a small Repro Claron 305 on it quite often and and am pretty satisfied. I seldom carry more than 3 film holders with me.

I have an 8 x 10 Linhof Kardan Bi as well and it is something of a beast to schlep around compared to the Seneca.

[gary mulder]

A 8x10 film holder weighs 710 gram. Three is ± 2130 gr. A Chamonix 4x5 is 1400 gram and a grafmatic is 470 gram. Together that's 1870 gram. Leave's minus 260 gram for a 8x10 camera. There is now way a 8x10 kit can be as light as a 4x5.

[Weihan]

A 8x10 film holder weighs 710 gram. Three is ± 2130 gr. A Chamonix 4x5 is 1400 gram and a grafmatic is 470 gram. Together that's 1870 gram. Leave's minus 260 gram for a 8x10 camera. There is now way a 8x10 kit can be as light as a 4x5.
I think I'm going to resign myself to the fact that I'm just not physically able to schlepp around an 8x10. Maybe one day I'll win the lottery and then can hire a team to carry the beasts for me along with a couple dozen film holders. I'll just be happy with the Linhof TK that I have and the nice set of lenses, but will continue to admire those that are able to work in the 8x10 milieu. Lucky devils that you are.

[Weihan]

That Ritter 8x10 may be lighter than your Technikardan, but the film holders and lenses will be significantly larger and heavier than the ones you use for 4x5.

As much as I love my TK45s, it's not the lightest 4x5 camera out there and it may be overkill for landscape work. Maybe something like a Canham dlc or a wooden folder would lighten the load?

Noah, I agree about the weight of the TK45, and I curse it every time I head out. But it has been a great tool (as clearly evidenced by much of your wonderful work too!)

[Noah A]

Don't get me wrong, I love working with the Technikardan and the more I shoot with it, the more I realize it is perfect for the urban landscape work I do. I don't mind the weight since it is still a very compact camera considering that it offers monorail-like movements. I carry mine in a lowepro flipside 500, which makes for a relatively lightweight package.

I think 4x5 is a great format and not all of us think of it as inferior to 8x10. Along with the size and weight advantage, there are also advantages when it comes to depth of field, being able to use faster shutter speeds, etc. Of course in some ways you can't beat a huge piece of film, but 8x10 also brings some of its own problems.

[paulr]

Bob, any word on this? Are there newer lenses?


Bob, I'm looking at my Rodenstock datasheet for Digaron S and W lenses. Have the lenses been updated? The diagonal for 6x7 is 92mm. The only lenses listed that will cover that (with minimal movements) are the 70 and 90 HR Diraraon Ws. The sheet I have is called e_Rodenstock_Digital_Lenses_3-26__8236.pdf

What does the corrector plate correct for?

[Bob Salomon]

Bob, any word on this? Are there newer lenses?

The 90mm HR Digaron-W is discontinued and out of production. It was replaced with the 90mm HR Digaron-SW at the 2012 Photokina and is currently available but in extremely short supply.

We and the factory are completely sold out of the older 90mm HR Digaron-W.

The 70mm and all other Rodenstock digital lenses from 23 to 180mm are current and none have ever been discontinued.

The current literature on the Rodenstock web site includes the new 90mm SW lenses full specs.

[paulr]

I'm seeing now the line of apo sironar digital lenses, which have the larger image circles. I wasn't aware of these. Rodenstock is publishing MTF values at much lower resolutions than for the two Digaron lines, so it's hard to compare them directly.

[Bob Salomon]

I'm seeing now the line of apo sironar digital lenses, which have the larger image circles. I wasn't aware of these. Rodenstock is publishing MTF values at much lower resolutions than for the two Digaron lines, so it's hard to compare them directly.

The HR Digaron W series used to be called the Apo Sironar Digital and the HR Digaron S series was formerly the Apo Sironar Digital HR series. They changed the name in 2010 and all the Apo Sironar Digital HR lenses have already been renamed. The Apo Sironar Digital lenses are still having their name changed.

[Weihan]

[QUOTE=Noah A;992099]Don't get me wrong, I love working with the Technikardan and the more I shoot with it, the more I realize it is perfect for the urban landscape work I do.

Me, too, Noah. It is a fantastic camera and does everything it's meant to do with great precision. But I, too, wish it were lighter (maybe made out of titanium instead of the alloy Linhof has used), but that of course would also increase the purchasing price. Do you ever use the Schneider Superangulon XL 47/5.6 on the TK? The lens is incredible, but very, very difficult to focus. I was thinking maybe something along the lines of a Fotoman 45 PS just for that lens. Do you have any tricks you use with the 47mm XL?

[Bob Salomon]

[QUOTE=Noah A;992099]Don't get me wrong, I love working with the Technikardan and the more I shoot with it, the more I realize it is perfect for the urban landscape work I do.

Me, too, Noah. It is a fantastic camera and does everything it's meant to do with great precision. But I, too, wish it were lighter (maybe made out of titanium instead of the alloy Linhof has used), but that of course would also increase the purchasing price. Do you ever use the Schneider Superangulon XL 47/5.6 on the TK? The lens is incredible, but very, very difficult to focus. I was thinking maybe something along the lines of a Fotoman 45 PS just for that lens. Do you have any tricks you use with the 47mm XL?

Why would it be any more difficult then focusing the 35mm Apo Grandagon on a TK? You should be using a Linhof Fresnel with a Linhof ground glass or another matched GG/Fresnel system and the wide angle bellows.

If you have had some type of third party gg/Fresnel system installed then it may have been optimized for too long a focal length lens for optimal use with extreme wide angle lenses.

[gary mulder]

[QUOTE=Noah A;992099]Don't get me wrong, I love working with the Technikardan and the more I shoot with it, the more I realize it is perfect for the urban landscape work I do.

Me, too, Noah. It is a fantastic camera and does everything it's meant to do with great precision. But I, too, wish it were lighter (maybe made out of titanium instead of the alloy Linhof has used), but that of course would also increase the purchasing price. Do you ever use the Schneider Superangulon XL 47/5.6 on the TK? The lens is incredible, but very, very difficult to focus. I was thinking maybe something along the lines of a Fotoman 45 PS just for that lens. Do you have any tricks you use with the 47mm XL?

Buy a Maxwell screen. :)

[Nathan Potter]

[QUOTE=Noah A;992099]Don't get me wrong, I love working with the Technikardan and the more I shoot with it, the more I realize it is perfect for the urban landscape work I do.

Me, too, Noah. It is a fantastic camera and does everything it's meant to do with great precision. But I, too, wish it were lighter (maybe made out of titanium instead of the alloy Linhof has used), but that of course would also increase the purchasing price. Do you ever use the Schneider Superangulon XL 47/5.6 on the TK? The lens is incredible, but very, very difficult to focus. I was thinking maybe something along the lines of a Fotoman 45 PS just for that lens. Do you have any tricks you use with the 47mm XL?

Weihan, I recently started using the Schneider 47 XL with my TK45s'. Had to resort to a bag bellows of course but also a recessed lensboard (20mm recess I believe). Works fine but yes the focusing is tedious. For a number of scenes I simply set a hyperfocal distance based on a 20 µm COC at f/22. Typically yields everything from about 8 ft. to ∞ in focus or if you can stand a 40 µm COC at f/22 everything from 4 ft. to ∞ will be in focus.

If you really want to push the DOF you can choose a COC of 40 µm at f/45 and get everything from 2 ft. to ∞ in focus.

No matter what screen you use you'll be limited to critical focus within the central region of it because the peripheral rays are so far off axis that even a tilting loupe is of little value - at least that's what I find. As you say, it's a great special purpose lens for 4X5.

Nate Potter, Austin TX.

[Peter York]

If weight is critical to you, there are lighter 4x5s. I use a Toho for backpacking, and it is a very nice monorail that can accomodate very wide to very long lenses (with a top hat).

[Weihan]

Thanks Peter. Yes, I read a positive review of one posted I think by K. Thalmann, but the company seems to have gone out of business. If you hear of any news about them, please let me know.

[paulr]

Weihan, it might be worth it to ask about all this on the getdpi.com forums. A lot of guys there have technical cameras and all the related lenses and toys.

[Weihan]

Weihan, it might be worth it to ask about all this on the getdpi.com forums. A lot of guys there have technical cameras and all the related lenses and toys.
I'll check out the forum there; thanks very much for the information! I'll have a browse through their offerings and see what is being discussed in the way of technical cameras etc. It's always good to hear about additional sources, and I wasn't aware of this site at all. Cheers!

[Weihan]

[QUOTE=Weihan;992317]

Weihan, I recently started using the Schneider 47 XL with my TK45s'. Had to resort to a bag bellows of course but also a recessed lensboard (20mm recess I believe). Works fine but yes the focusing is tedious. For a number of scenes I simply set a hyperfocal distance based on a 20 µm COC at f/22. Typically yields everything from about 8 ft. to ∞ in focus or if you can stand a 40 µm COC at f/22 everything from 4 ft. to ∞ will be in focus.

If you really want to push the DOF you can choose a COC of 40 µm at f/45 and get everything from 2 ft. to ∞ in focus.

No matter what screen you use you'll be limited to critical focus within the central region of it because the peripheral rays are so far off axis that even a tilting loupe is of little value - at least that's what I find. As you say, it's a great special purpose lens for 4X5.

Nate Potter, Austin TX.
Those are very interesting figures, Nathan, and your values seem to reflect my own experience even though I haven't actually measured the COC. You've precisely understood the focusing issue in the corners of the GG, which is problematic even with a loupe like the Silvestri tilting one. There is very little tolerance for any movement with the 47mm XL, but it does deliver astonishing results. I do have the wide angle Maxwell screen, which improved things considerably, but the process is just as you've described - tedious. Do you have any images posted using the 47mm? Thanks for all your help!

[genotypewriter]

Has anyone ever compared the IQ of shots taken with a view camera + a 6x7 / 6x9 FILM back using a Schneider or Rodenstock digital lens versus a 4x5 film image shot with a traditional analog lens?

Haha wondered that a long time ago myself. Thank goodness I'm over it :)



Most of the Rodenstock ones have image circles of 120 to 150mm so they will cover most roll formats with no problem.
But be aware, The Rodenstock HR Digaron-S series and the former Rodenstock Apo Sironar Digital HR lenses require a correction plate mounted to the rear of the lens if these lenses are used with film. This is because the last element in the formula of these lenses is the cover glass over the sensor on digital backs. If the corrector plate is not used then the image will be slightly out of focus on film.

I think that's mostly true if you're using a sliding back. The flat piece of glass should only shift the focus... same happens when I take the clear-filter off lenses with drop-in rear filters. Same also happens when the IR/AA filter is replaced on digital cameras with specialised ones of different thicknesses. If focusing on GG as you'd do for film, I can't see how the lack of such plates can be an issue.



Based on experience with both 6x9 and 4x5, though, and assuming the same film for both 6x9 and 4x5 and appropriate working apertures in each case, I doubt very much that you're going to get "much higher resolution on film" with the 90 A-S-D on 6x9 compared to, say, a 135 Apo-Sironar-S on 4x5.

My thoughts exactly. There's always the issue of chunky grain with smaller formats... regardless of how infinite the optical resolution can be :D

[Bob Salomon]

"I think that's mostly true if you're using a sliding back. The flat piece of glass should only shift the focus... same happens when I take the clear-filter off lenses with drop-in rear filters. Same also happens when the IR/AA filter is replaced on digital cameras with specialised ones of different thicknesses. If focusing on GG as you'd do for film, I can't see how the lack of such plates can be an issue."

Then you are more then welcome to use the lenses without them. But don't complain when you find that the lens is not up to spec with film since you want to leave out the last element when used with film.

[Emmanuel BIGLER]

The purpose would be to shift the image back very slightly, most likely.

Yes, but not only. Of course the image as formed through a piece of flat glass is shifted by an amount of about 1/3 of the glass thickness (depending on the refractive index of the glass, the actual formula is : shift = t.(1-1/n) ; this yields t/3 when the refractive index n=1.5).
Hence as mentioned, the first advantage of the plane compensating glass is that if your lens is mounted on a calibrated helical with infinity stop, you do not have to change the mechanical setting of your infinity stop either with a silicon sensor or with film, since the total distance between the last lens vertex and the image, including the glass thickness, will be the same whether you use a digital sensor with cover glass (behind a "glassless" lens), or "bare" film (behind the glass-compensated lens).
The fact that this compensating glass can be located either near the image plane or just behind the last lens vertex is a non-trivial issue, and a purely paraxial analysis, found in all good textbooks of geometrical optics, yields a paraxial focus shift equal to t.(1-1/n) wherever the glass plate is located (this is an elementary analysis, valid only for a very narrow beam of rays at very small incidence angles).

This elementary paraxial analysis does not explain aberration issues at high angles of incidence, as briefly discussed below.
So, even if it is very convenient to be able to swap from a silicon, glass-covered sensor to a "bare" film detector without changing the infinity stop of the helical mount, this is not the real issue for high performance lenses delivering the maximum possible image quality. The problem is that introducing a flat glass inside a converging beam of rays introduces some amount of spherical aberration & other image defects. This has been known for microscope lenses for at least one century ;) and so-called 'biological' microscope lenses are internally compensated to see through a 0.17 mm piece of covering glass of a standardized type (mostly, a given refractive index and a given 0.17 mm thickness). At high magnifications, light rays entering a microscope lens are very oblique, and without the internal compensation of the lens for a given, standardized covering glass, spherical aberrations generated by the covering glass would blur the images. This is not really visible with a low magnification microscope lens like a 5X, but with a 50x or more, this is really visible. Metallographic microscope lenses are not compensated for this and should directly look at the surface of the object without any glass cover.

So far, this effect of additional aberrations when a flat glass is introduced through a converging beam has been neglected in most photographical situations e.g. when introducing a filter behind the lens. People in the past used to care for the paraxial image shift ~ t/3, not for the degradation of image quality.
A well-known example is the [OFF-TOPIC] infamous plane glass introduced for the Rolleiflex TLR in the 1960s. This plane glass applied against the film itself was supposed to improve film flatness, but nobody cared for additional aberrations. Actually, Rolleiflex users cared for additional dust and parasitic reflexions, but this is another story.[/OFF-TOPIC]

[Brian K]

A few observations, and maybe some answers for some of the wide range of questions posed here.

First, MF will never equal LF, no matter the lens, except it will come closer at smaller reproduction sizes. But still compare an 8x10 contact print to an 8x10" print made from a MF camera and you will see a difference in the smoothness of the gradation.

The lenses on the Mamiya 7II are by far the sharpest lenses I have ever used. And I have done head to head resolution testing between them and my Rolleiflex glass, hasselblad glass, Fuji GX680 glass and my 3 dozen view camera lenses. The film being examined under a microscope. However I can well understand that people do not like the look of the Mamiya lenses as they can appear harsh and have poor OOF qualities.

I can't recall if the original poster talked about the final out put of the image, silver or inkjet. Inkjet prints can enlarge vastly higher, and keep what seems to be much better image quality at much greater magnifications. I have images shot MF that I would never consider enlarging on silver past 24-30" that can go up to 70" on pigment. So one solution for the original poster might be digital output.

As for roll film backs, I own a few Sinar Zoom and Zoom II backs. They are bulky but they do hold the film flat and have the advantage of not requiring that the GG be removed from the camera, not a minor point when working in the field. They also have the advantage of being able to switch format sizes on the fly. One has to make certain though that their camera back can hold both their thickness and their weight. I used to use them with a Canham 45 DLC and the weight of the RFH would tilt the back out of focus. Not an issue with a more rigid camera though. On my Sinars and Linhof Technika MT 3000 there are no issues.

I have found that the highest image quality with the smallest dimensions and weight combination is a Technika and a sinar zoom II. The technika is super rigid, folds down quite small, has no protruding rail, uses small lensboards, and the zoom back is not much bulkier than 2 4x5 holders. But note that I prefer to shoot 6x12 cm, if you prefer a more squarish format, 6x9 or 6x7 proportions then the zoom will have to be set accordingly and now you are using 3 1/2 inches of film width instead of 4 1/2". The IQ of this is quite high, I have 40" silver prints from this and from the look they could go 50 or 60". For a digital output these images could easily go 80-100"

[Nathan Potter]

Emmanuel, I think you have identified the concern I have about the use of a sensor cover glass with any lens not designed for cover glass use.

As you point out in microscopy objectives with higher magnifications and short working distances have far off axis rays and the path length through a cover glass is longer than rays on axis. Thus there will result a focus shift with a radial dependence (spherical abberation) in the image due to, I believe Snells Law, as you point out. This can only be avoided in camera objectives if the optics are infinity corrected at the image side. Do I read you correctly?

I apologize for what I suspect is a poor en francais translation.

Nate Potter, Austin TX.

Emmanuel, je pense que vous avez identifié ce qui m'inquiète à propos de l'utilisation d'un couvercle en verre du capteur avec n'importe quel objectif n'est pas conçu pour être utilisé couvercle en verre.

Comme vous le soulignez dans les objectifs de microscopie avec un grossissement plus important et courtes distances de travail ont éloigné les rayons axe et la longueur chemin à travers un couvercle en verre est plus longue que celle des rayons sur l'axe. Ainsi, il en résultera un décalage de focus avec une dépendance radiale (aberration sphérique) dans l'image raison, je crois que la loi Snells, comme vous le soulignez. Ceci ne peut être évité dans les objectifs de caméra si les optiques sont corrigés à l'infini sur le côté image. Dois-je vous avez bien lu?

Je apol; ogize pour ce que je soupçonne est une mauvaise traduction en francais.

Nate Potter, Austin TX.

[Bob Salomon]

"A well-known example is the [OFF-TOPIC] infamous plane glass introduced for the Rolleiflex TLR in the 1960s. This plane glass applied against the film itself was supposed to improve film flatness, but nobody cared for additional aberrations. Actually, Rolleiflex users cared for additional dust and parasitic reflexions, but this is another story."
A better example was the glass plate used in the Hasselblad Polaroid back to get the image plane closer to the roll film image plane.

[Brian C. Miller]

My thoughts exactly. There's always the issue of chunky grain with smaller formats... regardless of how infinite the optical resolution can be

Personally, I'd love to see the SPUR (Adox CMS II 20 or Rollei 25 tech pan) film shot on MF with a "digital" lens and then compared with LF. The 35mm shot they had didn't hold up, but it would be very interesting to shoot it in 645 and 67 formats and compare those with 4x5 and 8x10.

One of the main problems with small-format ultra-high resolution film is the enlargement. The smaller the film, the more difficult it is to preserve the details in an enlargement. Also, if the technical film is compared to a film with a different curve, that will also throw off the results.