It Happened! 500cm Woes

Discussion in 'Medium Format' started by Ricochetrider, Jul 24, 2020.

  1. The resolution of Velvia is described in two ways: high contrast (1000:1) targets, and for normal (6:1) contrast scenes. The resolution is cited at 160 and 80 lp/mm respectively. This is the extreme limit, where the transfer function is extrapolated to zero contrast. At a more practical contrast of 50%, the resolution is about a third the ultimate value.

    The "affordable" LS-8000 resolves close to 4000 ppi, or 160 p/mm, a good match for Velvia. It requires the equivalent of about 25x magnification to make those pixels visible to the eye. At that point detail in a transparency is seen to be far less than the scanner can resolve. Even at 10x, you can see the "peppercorn" grain characteristic of Velvia.

    That is a pedantic answer. In practice it is not the resolution but the appearance of "sharpness" or acutance that counts. In theory resolution of digital is limited by the size of the pixels. In practice, each pixel counts, giving high acutance.
     
    Last edited: Jul 30, 2020
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  2. At that point, Ed, you see that among the noise and grain, there is still a change in pixel
    content that is due to a (resolved and recorded) change in the subject.
    The resolving power of the Nikon is not wasted on dye clouds.

    I'm almost tempted to find that example i posted many years ago...

    Pointing out that - as Zeiss reported before, as mentioned by me - people tend to appreciate contrast and cleansiness more than resolution, hence mistake a clean low resolution image (your 16 mp thingy) for the 'sharper' one will explain your mistake.
    A mistake it still is. A scanned MF image holds much more detail than a 16 mp image.
    And it can and will look much better too. If you want to compete on appearance, you need much more than 16 MP. About 3 times as much (and then you will still be lacking in resolving power).
     
  3. I attach a comparison between MF film and (almost) the same scale taken with a 16 MP digital back. In the sub-panel, film is on the left and digital on the right. Different balloons and several years apart, but the closest I can find of similar scenes. Even the weather is pretty similar (film does not do as well against a bright cloudy sky). Compare the detail in the basket, lines, and faces. The original images were 8400x8400 px and 4080x4080 px respectively, resized for comparison.

    If you had a digital back, would you want to spend $20-$28 per roll for film?

    A0001646.jpg Comparison.jpg M040703c_10.jpg
     
  4. There is a lot of good information about film resolution. Some of the easiest reading is here:

    8×10 film vs IQ4 150mp Comparing 8x10 to a 150MP Phaseone and Nikon D850


    Big Camera Comparison 2011 comparison but information about various sized film. 120 Tmax rated from 50Mp to 152 Mp

    So it does appear film has a fairly high resolution, much more than 16Mp. But digital is much easier, faster and cheaper in the long run.
     
  5. It is significant that the tests cited by David Hoyle were made using extreme wide angle lenses for each medium, 8x10, MFD, and the Nikon D850. 110 mm was used for the 8x10 camera, 23 mm for the Phase One and 12-24 for the Nikon D850. The lens designs require major compromises in order to allow relief for the mirror. I suspect lens quality is a significant factor in the relatively soft results. The Nikon D850 has 36 MP, but is handicapped by an anti-aliasing filter, which deliberately reduces resolution to about 50% below that of the sensor.

    Luminous Landscapes website is probably the most prolific source for practical MF digital photography. The came to the conclusion than reflex bodies and lenses were not up to the challenges of high resolution (>36 MP) digital photography. Their tests at 100 to 150 MP were conducted using mirrorless technical cameras like the Alpa and lenses specifically designed for digital.

    One expects aliasing when the target frequency exceeds that of the sensor, as seen in the second example using resolution targets. In this case, the sharper the lens, the more pronounced the aliasing, including diagonal color bands. They did not occur in this example, which suggests the lens had significantly less resolution than the sensor.

    Vignetting in the 8x10 examples, supposedly caused by a filter mount, are not what I would expect of a careful technician trying to benchmark and compare cameras and media.
     
  6. Ed,

    The significant bit to remember is that - despite, also, what Ludicrous Landscape might say - film has much more, retrievable, resolution than what you would want us belief.
    Lens design does not play a part in this.
    It takes quite a bit more than 16 MP to better film.

    The D850, by the way, has almost 46 MP, and no anti-aliassing filter.
    Nor had it's predecessor, the 36 MP D810.
    The also 36 MP D800E had one, but also had an anti-anti-alias filter, so in effect it had none.
    The even older D800 had an AA filter.

    Vignetting on 8x10" is due to the lens' coverage, or rather lack thereoff (that particular lens is made to cover 4x5". Anything more is a bonus. It was used to match the angles of view). Not to uncareful handling. It doesn't matter for neither the test not its conclusion. Does not need drawing attention to. Red herring.

    Ludicrous Landscape is evidently wong about reflex bodies and their lenses are not up to the task of recording more than 24 MP. Try a D850 (or a PhaseOne back on a Hasselblad or ex-Mamiya) and you will see.
    And try some film (again), scan it properly, and then also you will see for yourself.
     
    Last edited: Jul 31, 2020 at 8:09 PM
  7. My film scan is grain-sharp. What more can you get from a scanner?

    The "pro" articles used a D800, not a D850. I mis-typed in my response. The D850 is a fine camera, except it has a mirror, and is mostly limited to Nikon lenses.

    I use a Sony A7Riii, and having compared native lenses with Nikon lenses on the same camera and scene, they're not worth the bother. I have an adapter for Hasselblad V lenses too. They're good if not great, but weigh more than the camera and don't come any shorter than 40 mm.

    Any way, I could post any number of other examples with the same results. Others can judge for themselves.

    An Hasselblad is fun to use, and medium format film is a lot more detailed than 35 mm. It's easy to carry two or more types of tilm, and change them out without losing a frame or two. Best of all, you can make it digital for about the same price as a Leica M-10R, or a full-sized Nikon or Canon.
     
    Last edited: Jul 31, 2020 at 10:20 PM
  8. Yes, I've seen that utter BS from Zeiss. And if any readily-available commercial film really was capable of resolving 160 lp/mm or more, then we wouldn't have bothered with expensive Lippmann plates and UV exposure equipment when I worked in the micro-electronics industry.

    Besides, all resolution comparisons assume perfect focus of the target. How often can you exactly focus a film camera? Not as often as you can by zooming in on a live view digital image I'm sure.
     
    Last edited: Aug 1, 2020 at 7:04 AM
  9. Lipmann plates, as you know, are at least a factor 2 better. Why are we talking about Lipmann plates?
    You may call it BS, Rodeo. Doesn't make it so. 160 lp/mm, and more, is quite realistic using commercially available films.
    Yes, you have to take care not to mess up in any and all possible ways available. So?
     
  10. Ed,
    The comparison that demonstrated how good scanned film is used a D850.

    That the D850 has a mirror is not a disadvantage. In fact, short focal length lenses for digital are deliberately made retrofocus (and would have no problem with the space taken up by a mirror) to improve the lens-sensor interaction and get better results.
    Mirrorless cameras are great for allowing room for adapters. When you feel no need (and there is none using good Nikon F mount lenses) to adapt other brand lenses, that's a rather meaningless thing, an empty advantage.

    My film scans are also grain sharp. And give me much more real image detail than your 16 mp assertion would have us believe would be possible. Just read the article.
    What happened to the 72 mp plus you mentioned earlier in this thread?
     
  11. No it is not!
    I challenge anyone to produce a picture on Velvia, or any other useable speed commercial film, that clearly shows any resolution above 100 line-pairs/mm. With 80 lp/mm being about the practical limit.

    Where is the evidence for these ridiculous claims?

    Sure, in a lab, with a contact resolution-plate illuminated by a monochromatic parallel light source, you just might be able to get close to 160 lp/mm. In a commercially-bought camera and with a white-light illuminated 3D subject - absolutely no way.

    The micro-electronics reference is completely relevant. You don't get 2 micron features (> 250 lp/mm) easily and using off-the-shelf gear that you can buy in a camera shop.

    OTOH, I can show you that my digital Sony a7Riv easily resolves a bar-chart at 125 lp/mm - and through a very affordable lens - which is very close to its theoretical limit.
     
    Last edited: Aug 1, 2020 at 8:54 AM
  12. Why are we even having a film-digital debate in 2020? I thought that was settled 15 years ago!

    I will continue to shoot film because I enjoy the process, the look of the results, and like using the cameras. I will continue to shoot digital because it's in nearly every way better.
     
  13. That's the size of the raw scan, subject to pre-scan cropping.
    It was settled, which is why I could afford an Hasselblad in the first place. Other than occasional group pictures, it was never a working camera for me, but fun to use. If using film gives you pleasure, why not use it?

    It is true that better wide angle lenses for mirrorless cameras are retrofocus, but to a far less extent than for an SLR. The space vacated by the mirror box is used to improve the image quality. They can be used wide open and remain sharp in the corners.
     
  14. Yes, for me film is a hobby and something I enjoy using. I get a lot of enjoyment from using good Nikons(all of the single digit cameras, and plenty of others), my Hasselblads, and the Pentax 67, as well as dealing with the quirks of other oddball cameras I run across. I enjoy the fact that it makes me step back and think before I shoot, and I like the technical challenge of getting good results out of the limited dynamic range(compared to digital) of transparency films. I love seeing a big Velvia frame jump off the light table.

    I intentionally use my Hasselblad and Tri-X or FP4+ at times for photos that I know others will want. I especially enjoy the work of seeing my interpretation coming to life in the darkroom, and delivering the finished result to other people. A skillfully printed darkroom print(not that I'm particularly skilled at it) has an aesthetic quality that is hard to match with anything else. It's not technically better or worse than other media, but just a look that many people, myself included, really like.

    I'm perfectly content using a full frame Nikon DSLR, though, for any other purpose. Aside from MF digital being out of my budget, I work a lot with wide angles and appreciate that this is one area where-to me-the 35mm format has always hit the "just right" spot in terms of practical use(although 4x5 lenses down to 65mm or so tend to be good and aren't particularly exotic either, but can be temperamental to use without things like recessed lens boards and bag bellows).

    With regard to retrofocus lenses, even "normal" lenses for most SLR systems are at least a slight retrofocus design. The F mount, for example, with its 46.5mm flange distance, makes it awfully difficult to get a 50-60mm lens without doing that. In fact, Nikon's first f/1.4 SLR lens was 58mm so that they had a bit more freedom from that. The 74.9mm distance for the V system puts you in the same situation with an 80mm lens. I've heard it argued(with no definitive conclusion) that the 80mm f/2.8 Planar on the Rolleiflex was better than the same V mount lens for this reason, although in the real world I suspect it's splitting hairs and both are excellent lenses.

    And yes, to your point on mirrorless, something like a 20mm lens needs wouldn't get along overly well with a typical 24x36mm sensor with the rear element that close, but you still don't need as much of a retrofocus design as on a 20mm SLR lens.
     
  15. If you remove the lens shades, the Zeiss Loxia 21 is almost twice the length of the 50, and nearly as long as the 85. The smallest of the set, the Loxia 35, is a plain-vanilla Biogon design with moderate retrofocus design. The front node distance is 55 mm. The 21 is a strongly retrofocus Distagon, with a front node distance of 67 mm. I use this lens for wide-field astrophotography, wide open. Stars in the corners of the field are pinpoints. This was taken with the Loxia 25, which is very similar to the 21 (which I didn't have at the time).

    I would use the Hasselblad for starry skies, except the sky around Chicago is too bright, and the Hassie kit is too much to take to Seattle unless I'm driving. It's also much to heavy for my tracker (exposures longer than 10 seconds or so). I find Hassie lenses very sharp, even wide open.

    Sony A7Riii + Zeiss Loxia 25/2.4, Exposure 10 seconds at f/2.4, ISO 800. No tracker was used or needed.
    _7R30710_AuroraHDR2018-edit.jpg
     
  16. No. We're having a film debate over whether it's possible to get 160 lp/mm or even close, from any useable-speed film.

    I've yet to see any visual proof that it's possible.

    Digital only entered the argument as a comparator in terms of megapixels and as a point of reference.

    Personally, I've only seen 100 lp/mm resolved on 50 ISO B&W film - very poorly resolved among the grain I might add, and only in the central part of the image circle.
     
  17. The micro electronics reference is still not relevant, Rodeo. To find out if Velvia or any other film can capture 160 lp/mm in normal photography, it really is of no importance what you need to achieve 250+ lp/mm

    With 80 lp/mm being the limit of what an affordable scanner will resolve, i can't show you, Rodeo.
    But that 80 lp/mm is resolved and (!) reproduced when you scan (with that affordable scanner presenting the hard limit). Not just possible when wet printing.

    Indeed, it is a film debate.
    Even in these times, when film is still available, though for many purposes not the tool people would turn to, it is good to know what it is capable of.
    Film vs digital debates have always been rather silly, i'd say. As if the outcome would be that there is a clear 'winner'. Both media are different. Both have their own strong and weak points.
    The thing that made digital appear to be the 'winner' of these debates was what would have both pleased and annoyed George Eastman: it made photography 'easy' for absolutely everyone, amateur, pro and specialist image capture alike. But the thing to remember is that all tools leave their mark. Film is not only still quite good, but also different. Use that difference to your advantage, if and when it helps to get what you aim for. Just like, say, switching from 40 mp small format digital capture to 40 mp medium format digital capture can make a lot of sense. Even though many people would shrug off such a proposal because all they hear is "40 mp" and "40 mp".
    Given that, given that the outcome is that most people do not even know film, and that many who do do not know when to use film while still available, i'd say the old film vs digital debate hasn't been settled at all.
     
    Last edited: Aug 2, 2020 at 7:22 PM
  18. Very interesting debate but for the most part over my head. I do wonder if actual photographers really consider these things when making a picture. I don't think Robert Frank would have cared, or Edward Weston or a host of others. Great pictures, even good ones, arn't dependent on any of these considerations.
     
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  19. Is the argument now also that for a scene with a contrast range in a scene with normal pictoral range(6:1), Velvia can resolve better than the manufacturer claims?(80lp/mm per the datasheet).

    Perhaps it would be worth writing Fuji to tell them that they don't know anything about their products, and in fact that your dye-cloud resolved images from a Nikon 8000 show more resolution than the manufacturer claims.

    I've been enjoying looking at some fresh-from-the-lab RVP50 taken in my Pentax 67 the last day or so. Perhaps a scan in my LS8000 would be worthwhile, even though I've scanned hundreds of frames of Velvia and other film with it in the past.
     
  20. Well the film "debate" is about as worn as the debate over analog VS digital in audio recording too. Turns out that a lot of folks have reverted to analog audio for the base and primary sources prior to digitizing because....

    At the end of the day, folks will argue to the death that one beats the other. There will always be people who have "moved on" to whatever the new or "modern" fad is.

    Meanwhile there are are mass numbers of *us* who are quietly
    (or not so quietly, as the case may be)
    shooting modern film on antique cameras with antique lenses, and listening to records on old or new turntables through tube amps.
    Each to their own certainly.
    We won't all agree nor do we need to.
     

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