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Author Topic: Backs and LF films resolution according to Burtynsky  (Read 11750 times)
Jack Flesher
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« Reply #40 on: November 17, 2010, 01:41:25 PM »
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...so, if we want a really large print, and Apo-Digitars do not have enough image circle, shift-and-stitch on 5*7 with a good LF lens is a viable option, and a good alternative to pan-and-stitch?

LOL excellent point!  

Actually, I left both 4x5 and 8x10 film at the same time (sold everything, lenses and cameras), and I told myself if I ever came back to LF film I would shoot 5x7 --- and for a few reasons: 1) most modern 4x5 lenses adequately cover 5x7; 2) a 5x7 camera is not significantly larger to carry than a 4x5 where an 8x10 certainly is; 3) I prefer the 4:3 aspect ratio most of the time, and it's an easy crop from 5x7 to 5x6.7; and 4) you net almost 2x the film area from 5x7 compared to 4x5 when both are cropped to a 4:3 aspect. (And with that 2x film area, I think you could comfortably shoot a shorter lens and forego the shift and stitch Wink ...)  

You could do a lot of great landscape shooting with 5x7 camera, a few film holders and a 110 (SSXL), 180 and 300 lens kit...
« Last Edit: November 17, 2010, 01:46:59 PM by Jack Flesher » Logged

Dick Roadnight
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« Reply #41 on: November 17, 2010, 04:18:22 PM »
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...so, if we want a really large print, and Apo-Digitars do not have enough image circle, shift-and-stitch on 5*7 with a good LF lens is a viable option, and a good alternative to pan-and-stitch?

LOL excellent point!  

Actually, I left both 4x5 and 8x10 film at the same time (sold everything, lenses and cameras), and I told myself if I ever came back to LF film I would shoot 5x7 --- and for a few reasons: 1) most modern 4x5 lenses adequately cover 5x7; 2) a 5x7 camera is not significantly larger to carry than a 4x5 where an 8x10 certainly is; 3) I prefer the 4:3 aspect ratio most of the time, and it's an easy crop from 5x7 to 5x6.7; and 4) you net almost 2x the film area from 5x7 compared to 4x5 when both are cropped to a 4:3 aspect. (And with that 2x film area, I think you could comfortably shoot a shorter lens and forego the shift and stitch Wink ...)  

You could do a lot of great landscape shooting with 5x7 camera, a few film holders and a 110 (SSXL), 180 and 300 lens kit...
I was thinking of shift-and-stitch with a digital back, using LF lenses... you would have to invent a stitching back with enough shift.
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« Reply #42 on: November 18, 2010, 05:28:18 AM »
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Please can you expand on this. From my own tests it is striking how the best large-format film lenses approach their diffraction limit at their working apertures. The best medium format lenses for SLR systems are only marginally better at their working apertures and do not approach diffraction limit. Given the substantially larger area of 4"x5" and 8"x10" to even 6x7, let alone the <645 of medium-format digital, this presents a considerable overall optical advantage to larger formats. Of course resolution is not purely a matter of optics and there is significant resolution loss from film/scanning as opposed to sensor capture.
To come to that conclusion I did compare the MTF diagrams of the current Rodenstock lenses. Take the 40 lp/mm graph of the Digaron-S 60mm at f/5.6 for example, it runs very similar to what the Apo-Sironar-S 150mm does at f/11 for 20 lp/mm across twice the image circle. For 8x10" we can look at the Apo-Sironar-S 360mm which is only slightly better at f/22 for the corresponding lines across four times the image circle of the Digaron-S. This pattern even extends to Schneider's Fine Art XXL 1100mm lens which shows only a slightly better curve for 10 lp/mm at f/45.
The Digaron and Digitar lenses for technical cameras seem to be better than most MF SLR lenses. The best MTF for a medium format digital system I've seen so far is the Caldwell 120mm Macro UV-IR Apochromat. The overall optical performance seems to be very close to the Apo-Sironar-S 360mm. Of course the manufacturing tolerances on high resolution lenses for smaller formats have to be much tighter than for the big boys. So there might by a higher percentage of sample variations for digital lenses.

Here is a sample:

This has been my first 8x10" capture. Even though I like the image itself there are a few problems that make it unusable, the bellows shading only being the most obvious. Every step up in format opens new pitfalls to pay attention to.
The lens was a Rodenstock Apo-Sironar-S 240mm at f/16 on Fuji Pro 160S for a little over six minutes exposure time. In fact I scanned this image at 4500 ppi (1.5 GP and 10 GB file size). Back then I was still trying to find the right master file size for my 8x10" images. I even scanned a central chunk of that film at 6000 ppi. At that resolution the full image would be 2.65 gigapixel in a massive 17 GB file. Are there any RIPs that could handle such a file?

I prepared crops at different resolutions to give you an idea on how much pixel density you need to store detail at various contrasts. The crops were sharpened and saved as quality 12 jpegs. From there you can draw your own conclusions.
6000 ppi - 2.65 GP
4500 ppi - 1.50 GP (this is a 100% crop from the master file)
2400 ppi - 400 MP (downsized from the 4500 ppi scan)
1440 ppi - 150 MP (downsized from the 4500 ppi scan)

I didn't bother to spot the file. Spotting a multi-GB file is a laborious and time consuming process.

I'm reluctant to pinpoint the resolution of 8x10" to one number. I see it as a range where it takes a very high resolution scan to capture the finest high contrast details while on the other hand the lower contrast textures are getting lost in the film's grain structure. But like I said earlier I see the greatest advantage in smoother tonal transitions in very large prints compared to upscaling by software. The type of film used of course also has an impact. The Fuji Pro 160S has an excellent MTF. It's very fine grained for a color neg but coarser than the new Kodak Ektar 100. Color negs do shine in high contrast situations where the full dynamic range of the film is used. Under normal medium contrast light reversal film has a finer grain appearance.

What is the file resolution of such a 6gb scan?
Typical pixel dimensions for a 3600 ppi file of 8x10" film after cropping the film holder's edges is 34,700 x 27,500.

My own "conclusion" on how many pixels it took to match each medium, assuming the best possible glass being used for all mediums, was ~~50MP to match a perfectly captured and scanned sheet of 4x5 and ~~100MP to match a perfectly captured and scanned sheet of 8x10.  Corollary comment here is even when taking extreme care in my set-ups, I got maybe a 30% hit on the "perfectly captured" part for either 4x5 or 8x10. Not saying the other 70% were unusable, far from it -- just not "perfect."  (I had a much higher hit rate with the Betterlight because it had electronic focus confirmation and was of course a perfectly flat capture plane.)
Jack, even though I disagree with your MP equivalents for perfect LF exposures on film I do agree that it's almost impossible to make use of the format's full potential for the various reasons you stated. Often it's just some unintentional fall-off in sharpness that doesn't ruin the image but it does compromise the quality. I do mostly long exposures where the wind and the light travelling through the atmosphere can cause all sorts of trouble over time. I even heard of the possibility that the film could buckle inside the holder. Some faults cannot be traced back easily.

May I ask which lenses and what types of film you used for 8x10" back then?

...so, if we want a really large print, and Apo-Digitars do not have enough image circle, shift-and-stitch on 5*7 with a good LF lens is a viable option, and a good alternative to pan-and-stitch?
I was thinking of shift-and-stitch with a digital back, using LF lenses... you would have to invent a stitching back with enough shift.
Don't you think that it would be more effective to use a DSLR and a long lens on a nodal point adapter for super sized stitching? This way you're always using a high quality image circle of a long lens.

-Dominique
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hjulenissen
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« Reply #43 on: November 18, 2010, 07:23:39 AM »
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I have read Roger Clarks reports with great interest. Mainly talking about 35 mm but I guess the fundamental issues can be extrapolated?
http://clarkvision.com/articles/film.vs.digital.summary1/index.html

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ondebanks
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« Reply #44 on: November 18, 2010, 07:58:59 AM »
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6000 ppi - 2.65 GP
4500 ppi - 1.50 GP (this is a 100% crop from the master file)
2400 ppi - 400 MP (downsized from the 4500 ppi scan)
1440 ppi - 150 MP (downsized from the 4500 ppi scan)

It looks to my eyes that you need the 2400ppi to capture all the detail - the venetian blinds provide a handy source of fine modulation. 1440 ppi is definitely too low.


Typical pixel dimensions for a 3600 ppi file of 8x10" film after cropping the film holder's edges is 34,700 x 27,500.

-Dominique

Well then; scaling 34,700 x 27,500 from 3600 ppi to 2400 ppi gives a 424 Mpix file. Now we know what 8x10 is capable of! It certainly exceeds 152 Mpix (1440 ppi)
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John R Smith
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« Reply #45 on: November 18, 2010, 08:11:09 AM »
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Well then; scaling 34,700 x 27,500 from 3600 ppi to 2400 ppi gives a 424 Mpix file. Now we know what 8x10 is capable of! It certainly exceeds 152 Mpix (1440 ppi)

Well, when you think about it is hardly surprising, is it. Just imagine a digital sensor that big (8x10), or even 5x4.

John
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ondebanks
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« Reply #46 on: November 18, 2010, 08:55:36 AM »
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Well, when you think about it is hardly surprising, is it. Just imagine a digital sensor that big (8x10), or even 5x4.

John

I'm not in the least surprised. My emphasis was there, rather, to prod those who would claim that you can get 8x10 quality in << 150 Mpix.
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Fritzer
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« Reply #47 on: November 18, 2010, 09:19:05 AM »
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Basically I'm just trying to justify my purchase of two apo-sironar-s lenses!  (They're my most expensive lenses.)

Don't worry about it - I have a couple of Apo Sironar (150 S and 180 Makro), and they hold their own against my digital lenses . Wink

Quote
In other words, I've found that while they perform unremarkably over a small area of the frame (at least by small format standards), the full image still looks great.  Due to the increased sensor size (16 times the surface area of 135 film or an FX digital sensor), they only need to perform 1/4 as well as a dslr camera lens or 1/3 as well as a lens for 645 to give the same contrast and detail to the given frame size.  And, according to mtf charts, they perform at least 1/4 to 1/3 as well as the very best!  Which sounds terrible (and kind of is), but is pretty good in practice, since they're less expensive than the very best and allow for generous lens movements.  And by normal working apertures (f11-f32 depending on focal length) you're losing most of your resolution to diffraction, not lens flaws, anyway.

Well put, only I don't see the value of the mtf charts if the conclusions are what you say they are. Also keep in mind LF lenses where almost never developed for sheet film only .

[/quote]I have been really impressed by the 8x10 enlargements I've seen.  They put 4x5 to shame, but mostly in terms of tonality, not contrast.  100 megapixels could likely match that, though, but with a different "look."  Stitching might be the ultimate solution, if the scene permits.

[/quote]

Good point; tonality is where the larger LF formats really shone. You loose an incredible amount of 'data' when you make an analogue print, yet the tonality somehow gets through .
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Dick Roadnight
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« Reply #48 on: November 18, 2010, 09:27:05 AM »
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...so, if we want a really large print, and Apo-Digitars do not have enough image circle, shift-and-stitch on 5*7 with a good LF lens is a viable option, and a good alternative to pan-and-stitch?

Don't you think that it would be more effective to use a DSLR and a long lens on a nodal point adapter for super sized stitching? This way you're always using a high quality image circle of a long lens.

-Dominique
I have bought an HC 300mm with this in mind... but Nodal point pan-and-stitch is less than ideal for architecture...

Would a hex-stitched image from a good 400mm LF lens be better than a multi-shot with an Apo-Digitar 210mm? If the image included a moving boat, 400mm LF might be better than single shot hex-stitch?

If I do not intend or expect to use film again, is there any point in keeping my LF kit?
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Jack Flesher
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« Reply #49 on: November 18, 2010, 10:43:08 AM »
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Jack, even though I disagree with your MP equivalents for perfect LF exposures on film I do agree that it's almost impossible to make use of the format's full potential for the various reasons you stated. Often it's just some unintentional fall-off in sharpness that doesn't ruin the image but it does compromise the quality. I do mostly long exposures where the wind and the light travelling through the atmosphere can cause all sorts of trouble over time. I even heard of the possibility that the film could buckle inside the holder. Some faults cannot be traced back easily.

May I ask which lenses and what types of film you used for 8x10" back then?
Don't you think that it would be more effective to use a DSLR and a long lens on a nodal point adapter for super sized stitching? This way you're always using a high quality image circle of a long lens.

-Dominique

No offense taken -- those stated values were more or less subjective impressions by myself and associates I respected based on our own results over our  combined years of shooting side-by-side and comparing.

My preferred films back then were,

4x5: Pro160S, Portra 160 NC, and Ektacrhome E100 G

8x10:  Pro160S, Portra 160 NC, E100 G and my all time favorite, Vericolor III.  Long discontinued, but I had a reserve supply of it Smiley

My preferred lenses:

4x5: 65mm and 90mm SA MC Linhof badged, 110 SSXL, 150 APO Symmar L,  240 G Claron and 305 G Claron

8x10: 210 SSXL, 305 G Claron, 450 APO Ronar

I tested my lenses back then with the Betterlight scanning back in highest resolution mode.

Re DSLR and stitching.  Yeah, I even built a custom camera out of a Horseman L specifically to do that, and have the tee-shirt. At the end of the day, you got enough shadowing from the DSLR's mirror box it limited your widest AoV to basically a normal.  Then you had the issue of subject movement during the minimum 12 frames of capture, often even 24 frames and sometimes 48 frames.  In the end, it was far easier to shoot film and scan, and usually with superior results.  The BL scanning back was awesome as respected IQ and DR, and far more convenient and better IQ than the DSLR stitch approach, but it also suffered from subject movement.  The BL also had the added disadvantage of needing power and be tethered to a laptop which was inconvenient in the field to say the least --- again, I found film and scanning far more convenient.  (FWIW, there was an intangible Zen-like quality to exposing film on a view camera that I found very enjoyable, more so than direct digital, and that's probably the only reason I would go back to shooting a view camera and film again.)

Cheers,
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Bruce MacNeil
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« Reply #50 on: November 18, 2010, 08:10:19 PM »
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FWIW -

Ed shot mostly with 4x5 a while back - the Linhof and the Grandagon 75mm 4.5 a lot.

Of late he has been with the Blad 39 then the 50 and now the 60.

Ed is a super nice guy and very generous with his time and knowledge. He is diligent in terms of technique and applying discipline to the photo.

His lab in Toronto is great and the staff there super knowledgeable - if you want to get the most of your images they can sure help.
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« Reply #51 on: November 23, 2010, 11:28:48 AM »
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Hi,

I'd suggest that there is a lot of snobbery  involved. On the other hand there is another factor. Different optical systems have a specific signature. With digital we may have a tendency for perfection. Large format lenses were never perfect, if you look at MTF data for any of them they are just awful, but they may have some kind of character. Rodenstock Imagons come to mind.

So I'd suggest that it is snobbery and perception.

There is also an aspect of workmanship. Shooting a single sheet of film costing perhaps 50 USD (including processing) vs. shooting images with very little marginal costs.

Best regards
Erik



If MTF charts were the be all and end all in choosing a lens and equipment life would be much simpler. I never compared the mtf performance of my lenses on 35mm 6x6 or LF or my digital,  (I never look at mtf charts these days) regardless of what they were, the bigger the sheet of film used the better technical quality image was recorded. I shoot LF on occasion for the fun of it, like a painter takes an easel and paints into the country instead of copying a snapshot. I don't think it's all snobbery on the photographers part, although the galleries like a yarn to spin. Spot on with the workmanship thing, nothing like a bag of money to concentrate the mind. The whole experience and thought process using film and especially LF is different to digital. You need to make a lot more decisions about how the image will look upfront with film than you do digital.
I don't get this obsession with resolution, it is another aspect that digital has amplified the importance of, a bit like everyone now wants a fast lens to shoot the background out of focus. The next craze will be aperture blades when everyone realises it's the shape of the hole that gives good bokeh. Who really cares wether a P65 or 10x8 can show a couple more whiskers on a chin at 50 paces. It's content and always has been that counts.
It's a funny old world where we measure technical perfection a thousand ways and believe the better the figures the more emotionally moved we will be when looking at a picture. I reckon the finest old masters with a brush and oil painted at about 6 - 8 mega pixels resolution, yet we marvel at the detail they brought to life.

Cheers,

Kevin.
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Kevin.
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« Reply #52 on: November 24, 2010, 07:35:59 AM »
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I don't get this obsession with resolution, it is another aspect that digital has amplified the importance of, a bit like everyone now wants a fast lens to shoot the background out of focus. The next craze will be aperture blades when everyone realises it's the shape of the hole that gives good bokeh. Who really cares wether a P65 or 10x8 can show a couple more whiskers on a chin at 50 paces. It's content and always has been that counts.
It's a funny old world where we measure technical perfection a thousand ways and believe the better the figures the more emotionally moved we will be when looking at a picture. I reckon the finest old masters with a brush and oil painted at about 6 - 8 mega pixels resolution, yet we marvel at the detail they brought to life.

Cheers,

Kevin.
I agree about the first part. Resolution is only one of several aspects, and people/media tends to be fixated on one at a time, when it is the whole that matters.

I think that photography is (can be) both a technical and artistic venture. That is part of what appeals to me. And I find the artistic part a lot harder than the technical one.

I think that doing good, repeatable, relevant measurements is a good base for doing camera (equipment) reviews. It serves as a counterpoint to reviewer preferences and biases when subjective impressions are reported.

-h
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