I looked at Velvia 50 under a microscope today

Discussion in 'Film and Processing' started by thomas_lozinski, Jul 14, 2010.

  1. At 100x magnification the grain or grain clusters? were about 10 nanometers (0.01mm) in diameter
    Counting each grain or cluster as a dot would give 2540 dpi and would give 24mm x 100dpmm x 36 x 100dpmm = 8.6 million dots (grains, grain clusters). I really don't think you can get more resolution than this out of the film. I'd say my 12 megapixel camera looks better when blown up 100x (to 150 inches on my computer and looking at 100%) than the velvia did. I'm not trying to start an argument but just wondering if anyone else has actually gone and done this simple test themselves and would agree with me or correct me.
    I know there are some finer grained films than velvia but not many color films. Now I'm seriously doubting the higher claims of film resolution.
     
  2. 0.01mm = 10 micrometers (microns), not nanometers.
     
  3. When a microscope says 100 times magnification, is it a linear or area measurement? I am thinking area--no?
     
  4. SCL

    SCL

    The measurement is linear measurement.
     
  5. Yes, 10 micrometers, thanks for the correction. (can't believe I made that error.)
    The microscope was on 10x objective with 10x eyepiece but that is irrelevant since I was using a micrometer slide placed over the slide (slightly had to adjust focus) but I could get a good approximation of grain size.
     
  6. david_henderson

    david_henderson www.photography001.com

    If what you're saying is true, would that mean that there's no point scanning Velvia at any more than 2540 ppi because (for example) a 2540 ppi scan contains the same amount of detail as a scan made at say 4000ppi or way beyond that on a drum scanner?
     
  7. David, in general yes that is what I'm saying with a few caveats. My measurement was very quick and my micrometer only went down to 1 micron (although if anything the dye spots were a bit bigger than 1 micron.) Scanning at 4000 might give a slight edge since the 2540 ppi aren't going to be in exactly the same spot that the sensors array are in. I'm not taking into account bayer array sampling since the dye spots don't seem to only be one color (I may be wrong here.)
    This was just a quick very simple test and I encourage others with microscopes to spend 5 minutes and see what they see. I've spent way too much time reading different points of view on what is better and I should have just done this quick test myself instead.
     
  8. I'll examine a few Velvia slides under a microscope next week. I did it before, but I didn't take any notes. All I can remember is that I could see details that were not resolved in 4000dpi scans. I think that your conclusion wrong and that Velvia and other modern colour films hold a lot more information than your numbers suggest. Basically, dye clouds in colour film are not aligned in rows like cells in sensors (pixels, if you like), but are distributed randomly in different layers, hence counting them under a microscope, which has limited depth of field, in order to calculate the equivalent pixel count does not make sense, or at least is not as straightforward as one may think. That said, I am unable to tell at this time how exactly you are wrong, and it is only my opinion that you are. I hope I'll be able to find out based on my own observation.
     
  9. Here is a detailed film vs digital test.
    The DSLR Alpha 900 beats Velvia and the other films.
    http://www.boeringa.demon.nl/menu_technic_ektar100.htm
    I still shoot film 90% of the time.
     
  10. Measurement issues aside, film grain is not linear (grid) and cannot be counted as such. It "clumps" more around denser exposure than light/no exposure. A digital imager is a completely linear grid. You simply cannot "count" mega pixels from film; you would get different numbers with different exposures.
    In my opinion, this is largely responsible for the "film look" that digital cannot emulate. It may be why it is easier to get a pin sharp image from a digital.
     
  11. Lee
    When I said that my 12 megapixel camera looks better when blown up 100x that is exactly what I meant. I am not saying that the resolution is better. The velvia at 100x looks like a bunch of dots and isn't pleasing to look at. The digital image resized to 150 inches wide and viewed at 100 percent did look better, maybe because tones were smoothed out from photoshop interpolation. I can't say for sure that the camera has more resolution (especially considering only 3mp for blue, 3 for red). I would further say that the resolution of the film appeared to be less than the dot size as would be expected. I'm trying to be as objective about this as possible; I'm not taking a side. I shoot both film and digital.
    Yes, the microscope has a limited depth of field, but the actual emulsion is extremely shallow (at least compared to the thickness of the film.)
    The following much more in depth article agrees with my measurement for size of dye spot (10 microns) although they indicate resolution is slightly better at 8 microns. They also indicate that Velvia is capable of 4000 ppi (almost double what I estimated in my 1 minute experiment.) Note that they are doubling in the conversion from lp/mm to ppi because of Nyquest) If at any point in your workflow you are converting from film to digital (to scan or to print) you are going to have to take this into account.
    http://cool.conservation-us.org/coolaic/sg/emg/library/pdf/vitale/2009-10-vitale-filmgrain_resolution_v24.pdf
     
  12. david_henderson

    david_henderson www.photography001.com

    I can't contribute to the questions of physics and testing and what you have to do to compare film scans and digital photographs.. What I can say with considerable certainty is that Velvia over a couple of decades was used by a great proportion of landscape and nature photographers to whom detail and sharpness of detail have been very important. I'm just struggling a bit with the thought that all these people did this despite the fact that the resolution of their film turns out to be not very good at all. I'm also struggling with a view that its taken nearly twenty years for a guy to have a eureka moment which demonstrates that all these picky landscapers and tree photographers haven't actually been able to produce large detailed prints from scanned Velvia. Most of all I'm looking at some pretty detailed 36" sq prints I have here from scanned Velvia and wondering how my lab managed to make these prints (which don't seem to rely on distance for their impression of sharpness) from a film that won't scan at more than 2500 ppi?
    I guess I think that sooner or later you'll find a flaw in your measurements, or in the conclusions that you're drawing from them. I'm also pretty sure that I've seen threads on here about how much useful data can be extracted from film
     
  13. They also indicate that Velvia is capable of 4000 ppi (almost double what I estimated in my 1 minute experiment.) Note that they are doubling in the conversion from lp/mm to ppi because of Nyquest)​
    The author of the linked article uses MTF 30% as the native resolution of film, that is without using a lens, from the Velvia datasheet. He is very clear about it and it has nothing to do with Nyquist. The MTF 30% for Velvia according to the author is 80 lp/mm or 4064 ppi. It is unconventional to use MTF 30% as MTF 10% is considered the resolution limit. Using MTF 30% leads to lower resolution for film+lens (on page 16 of the linked article) as opposed to MTF 10%.
     
  14. I'm just struggling a bit with the thought that all these people did this despite the fact that the resolution of their film turns out to be not very good at all. I'm also struggling with a view that . . . all these picky landscapers and tree photographers haven't actually been able to produce large detailed prints from scanned Velvia. Most of all I'm looking at some pretty detailed 36" sq prints I have here from scanned Velvia and wondering how my lab managed to make these prints (which don't seem to rely on distance for their impression of sharpness) . . . .
    David, I think you are considerably overstating the degree to which Velvia is being criticized, if indeed it is being criticized at all; I do think the OP is probably roughly correct about its practical, real-world resolution limits (which imply that 35mm Velvia has about the same resolution as a typical Bayer-sensor DSLR of about 14 MP).
    Let's put this into a little perspective. Suppose we were to say that you get at least some useful image detail out of Velvia 50 scans out to 2800 ppi or so. If those 36-inch-square prints are from a 6x6 (as are most square prints, I suspect), then a 2800 ppi scan means you have about 171 ppi of real image detail to work with. With many subjects, 171 ppi of real detail is quite sufficient for a pleasing print. Indeed, the most widely-quoted limits of human vision of which I'm aware (0.5 minute-of-angle) correspond to about 380 ppi at a viewing distance of 18 inches, and that's for extremely-high-contrast black-and-white detail. For practical human vision of ordinary pictorial subjects, the Velvia print may not be leaving behind to much detail visible to a viewer with average eyes.
    Also, high sharpness, even at moderate resolutions (ever notice how Fuji's Velvia 50 MTF response graph is above 100% from about 2 lp/mm to about 25 lp/mm?) can create a fairly convincing impression of detail.
    You simply cannot "count" mega pixels from film . . . .
    Absolutely correct--they're too different. Any claimed equivalency is at best an approximation for a given set of conditions.
     
  15. The normal human eye with 20-20 vision can resolve detail as small as one minute of an arc (1/60 degree). At 18 inches the human eye can resolve 3.76 lp/mm or 191 ppi, not 380 ppi. At 10 inches the eye can resolve 6.76 lp/mm or 343 ppi.
     
  16. C. Sharon, our issue is not math, it's whether the limits of normal human vision are 1.0 MOA (you) or 0.5 MOA (me). I'm not sure exactly how 20/20 is defined, but I've known several people who were better than that (20/15, 20/10). I guess it depends how far out on the bell curve you want to go whether you want to say the limit is 1.0 MOA, or 0.5 MOA, or what.
    Obviously if your (corrected or uncorrected) vision is poor, that will be the limit of the detail you can see. But for my brother who is 20/15 or a little better in one eye, well, he can see detail finer than 20/20, if it is there to be seen. I'm pretty myopic, and even with my contacts, I only get to 20/25 or 20/30.
     
  17. Dave: From Wikipedia - In the term "20/20 vision" the numerator refers to the distance in feet between the subject and the chart. The denominator is the distance at which the lines that make up those letters would be separated by a visual angle of 1 arc minute
    http://en.wikipedia.org/wiki/Visual_acuity
    Of course there are individuals with better than 20/20 vision but 20/20 is the statistical standard for "perfect vision" hence it is used to calculate what the human eye can resolve.
     
  18. C. Sharon,
    I thought they were using nyquest from the math . . . 83lp/mm converted to dpi
    83lp/mm * 25.4mm/inch = 2108 line pairs per inch, unless a line pair is 2 dpi, one for the positive line one for the negative line?
    Les,
    That is the main point of my post. People should test stuff out and see what they find. That is a very useful test you did on the crayons (although it doesn't say anything about the dynamic range in ONE print.) You have shown that if you really screw up the exposure you can get a normal looking photo, but you haven't shown that ektar can capture highlights and shadows at the same time in your very evenly lit scene.) Still a very good test. It looks like you could have even gone farther with the Ektar especially since reciprocity would help you another few exposure values up. I'll try repeating your test with my cam and see what I get but I have a feeling it won't beat the Ektar
     
  19. Well I'm looking at a recent slide under a scope right now and am a bit surprised that you could make out the grain at only 100X. I'm looking through at 400X right now and would be hard pressed to say where one "grain blog" ended and the other started. That being said I'm not very good with a scope but will try to take some photos through the eyepiece later if desirable.
    However, I also feel that my digital capture (D80) of the image had superior sharpness, but not color. I do attribute this though to a great difference in equipment used. The digital was taken with a D80 and a 35mm FL. The film was taken with an old OM-10 manual focus with 50mm FL. Same aperture (don't know what it was) but of course the smaller lens will give better depth of field and the digital was certainly better focused. That has led me to the belief that to do a really accurate comparison one needs to shoot not only the same lens but also the same image sensing area.
     
  20. Can't say that I agree with you. I have looked at slow slides with a high-end microscope and high-contrast detail was resolved (by the microscope lens) much better than from a 4000 ppi scanner. I'd guess that to get a really clean scan you'd have to scan at 20000ppi and then downsample to your target requirement to avoid aliasing of the grain and to get all the detail crisply as it is in the film. The detail I looked at was a backlit spider web which is of course a very high contrast subject; with low contrast detail film can be really crappy.
     
  21. Thomas,
    I don't have an 100x microscope with a micrometer stage, but by any common sense measure, your estimate of the grain size of Velvia at 10 microns seems very large, perhaps by a factor of 10. The dye clouds will overlap and perhaps run together in certain parts of the image - clear blue sky, for example - which could be misleading you.
    If you wish to measure resolution, measure it directly, using an high-contrast resolution target and non-limiting optics. On second thought, that's already been done. Fuji publishes the results for Velvia, with the value of about 160 lp/mm for such a target, and a more modest 60-80 lp/mm for conventional subjects. The MTF50 resolution for an high-resolution target is still 45 lp/mm (comparable to your estimate).
    The best obtainable resolution (160 lp/mm) occurs when the density of the lines is barely discernible from the density midway between lines. This corresponds to an uncertainty of about 3 microns, placing an upper limit on grain size. Not all grains are the same size, and there is a significant amount of chemical diffusion and light scattering within the emulsion, so it's safe to say average size is on the order of one micron or less.
    A 12-13 MP FX DSLR looks pretty good by comparision because the MTF50 resolution is close to 60 lp/mm, which is what really counts in a print.
     
  22. This is as bad as it gets.Have no idea how the image from a 12 MP is as good as Velvia.You don't have to measure anything just look at them side by side.I know no fine art photographer who uses a 12 MP camera for his work.
     
  23. Les,

    I tried your test with my 6 year old digital camera. Here are the results there is a purple cast in the highlights after +7 and +8.
     
  24. I'm sorry but, after reading so many postings like this one i have to ask...What is the point and what are you trying to prove?? Some people go on and on about micro this and micro that and trying to compare film to digital. If i'm that bored that i have to look at slides under a microscope and count grains i would think i need help of some sort. In my opinion, film and digital are not the same, therefore you cannot compare them.
     
  25. Les,

    I tried your test with my 6 year old digital camera. Here are the results there is a purple cast in the highlights after +7 and +8.
    00Wruz-260339584.jpg
     
  26. M M , Jul 15, 2010; 05:21 p.m.
    This is as bad as it gets.Have no idea how the image from a 12 MP is as good as Velvia.You don't have to measure anything just look at them side by side.I know no fine art photographer who uses a 12 MP camera for his work.


    How many fine art photographers do you know who use 35mm camera for their work?
     
  27. OMG!!! Now we're going to debate film vs. digital under a microscope?
    Whats next,,,,?!!
     
  28. MM, exactly what Scott said.
    That's what we're discussing here, 35mm film. If you want to use medium format or large format film, obviously it provides a lot more detail than the aforementioned 12-14 MP, plus (relative to 35mm) finer grain for any given output size. Obviously what Velvia equates to (insofar as you can equate it) depends on how big a piece of Velvia you use. I see B&H has it in stock in 4x5, and lists 120 as merely out of stock (by implication, still generally available). I would expect 4x5 Velvia, with the right camera/lens/technique, to be capable of outresolving even a 60 MP medium format digital back.
     
  29. How many fine art photographers do you know who use 35mm camera for their work?
    There's one on the North Shore that uses an Olympus P&S. Remember! It's not the camera, it's the photographer ;-)
     
  30. How many fine art photographers do you know who use 35mm camera for their work?
    Gallen Rowell used exclusively 35mm.McCurry also most of the time.I agree in principle that the camera doesn't matter much but up to a point.Saw some tours in Yellowstone for Iphone photography where you are not allowed to bring anything else than the phone.Some guy has a bestseller on the subject(how to make great pictures with a cell phone).You make some snapshots nothing else
     
  31. Simple test? Seriously? Do you think anyone looking at your images is going to whip out their handy microscope and analyse them? If so, you may want to question your images. Unbelievable!
     
  32. Les,
    The first two were underexposed. I didn't change anything else besides exposure time (then adjusted exposure in camera raw.) I'm pretty sure the purple highlights wouldn't have resulted except for the fact that the light level outside the window was much more than inside. Apparently I could have gone farther, especially if it had been an evenly lit scene. I used a Fuji S3 from 2004 (no dog when it comes to dynamic range.)
    Frank, thanks for trying the test yourself. That was what I wanted people to do, not start a war over film vs digital. Try a lower magnification, 400x is pushing what a dry mount objective can do. Try 100x and you should clearly see the dye spots (which is different than the actual silver grains but what most people commonly refer to as grain.)
    Jorge,
    Point well taken. The test only took me 1 minute and it the only reason that I did the test was that I was horribly disappointed with a canoscan 9000f flatbed scanner that I was scanning my slides on. The scans totally looked like crap so I wanted to see what the slide REALLY looked like. Obviously there is way more detail on the slide than can be picked up by low end flatbed scanners (even if it claims 9600dpi.)
     
  33. Thomas, resolution is one of the least important aspects of a good image.
     
  34. Well scanned 35mm Velvia/Provia does produce more resolution than a D3/D700 but of course there are plenty of other issues that make using film an expensive pain. That said I still love it and I use much more of it now that my digital infatuation has faded rather.
     
  35. OP, as Edward indicated 35mm Velvia resolves 160 lpmm (this is over 4,000 true dpi) on a high contrast target. This is materially (about twice as much) higher than any 12mp camera for high contrast and fine detail.
    Since this is a fact (directly tested by many of us), you should use it to evaluate your methodology. Not the other way around (use your methodology to evaluate Velvia).
    At lower contrast the resolution goes down but not due to grain size or limitation.
    Try to take picture through the microscope and post it for discussion.
     
  36. At lower contrast the resolution goes down but not due to grain size or limitation.
    As you see in your microscope (or scanner), film is not really sharp. A sharply defined border (e.g., a resolution target) is spread out over several microns on the film in a roughly Gaussian fashion. As the target contrast is reduced, this spread makes it harder to distinguish edges from the background. As the frequency of the target lines increases, the spreads begin to overlap.
    This effect is quantified in the MTF chart Fuji (and others) post for film. Notice that the contrast is fairly level at low frequencies, but begins to drop at abut 20 lp/mm. It decreases to 50% at about 50 lp/mm and only reaches 160 lp/mm at zero contrast (extrapolated). This is with an high-contrast target, of course. In practice, MTF50 is the value which determines how sharp an image looks to the eye, and at values below about 25% lines and spaces are too dim to distinguish by eye, even with magnification.
     
  37. Of course there are individuals with better than 20/20 vision but 20/20 is the statistical standard for "perfect vision" hence it is used to calculate what the human eye can resolve.
    Not to quibble, but it is more accurate to call 20/20 "normal" vision rather than "perfect" vision.
    Buffy
     
  38. To conduct the experiment scientifically, the lens, exposure, and development of the film is critical. So if your looking at Velvia under a microscope shot with a cheap Vivitar lens and developed at Walgreens and claiming it can't out resolve digital, you're not going to have a fair comparison. If you shot it with a Leica or Rollei, exposed it properly, and had it developed at a top notch lab that keeps their chemicals fresh, then you'll have a fair comparison. Film has many more variables than digital. If the film is developed in bad chemicals, then the image will suffer. Film is a lot easier to screw up than digital. If anything in the chain of image capture and production is flawed, then the film image will suffer.
    From a non scientific observation, I have noticed that digital has a cleaner look than film, but film has a richer color density. The film can be cleaned up with software.
     
  39. Lot of confirmation bias in this thread... you guys need to relax heh...
    Confirmation bias... is a tendency for people to favor information that confirms their preconceptions or hypotheses, independently of whether they are true. As a result, people gather new evidence and recall information from memory selectively, and interpret it in a biased way. The biases appear in particular for emotionally significant issues and for established beliefs.​
     
  40. Here is what it looks like under the microscope. The ruler is 1 millimeter in length total divided in 100ths.
    I'm not set up to do microphotography so this was the best I could get aiming a point and shoot through the eyepiece. One more thing to realize is that if the dye spots/ resolution is half this means that the megapixel value would quadruple, not double. So when I say my estimation of dyespot diameter is about 10 microns, if I'm off by a factor of 10 (which could be true, this was a very quick test to get a general estimation) then the actual megapixel equivalency would be off by a factor of 100.
    00WsJc-260571584.jpg
     
  41. I don't think you are off by a factor of 10x but I think the dye clouds are closer to 6-8 microns instead of 10, IMO.
     
  42. If the dye clouds were 10 microns (8, or whatever) in diameter, Velvia could never resolve 160 lp/mm. This is known as a test of reasonableness, commonly called a "sanity check". To achieve this resolution, the maximum average diameter would be on the order of 3 microns. Perhaps you are observing something else in this photomicrogram.
    I can't seem to find professional microphotographs or detailed information, except for a reference attributed to Kodak regarding dye clouds in color print paper at 1.75 to 4 microns in diameter. Micrographs of film to discern structure are typically taken with cross-polarized light.
     
  43. Is it older Velvia? There was a problem with bubbles in the film base.
     
  44. Thank you Thomas.
    Try placing a semi transparent piece of diffuse paper (like the one that separates glass slides) between the light source and the film - an as close to the film as possible.
    Does the film look smoother this way? If so, what you might be observing are bubbles and/or imperfections on the film's protective base.
     
  45. So where does the 160 lp/mm come from? looking at the date sheet they only show the curve to around 65 lp/mm and at that point the MTF is already down to around 35% and dropping like a stone.
    Data sheet.
    .
     
  46. Thomas,
    I superimposed an actual 8000 dpi scan of velvia I took to a portion of your measuring tape TO SCALE.
    As you can see, there are clearly 2 black lines and 1 white line resolved within the 2 marks of you 1/100 mm scale. i.e. about 160 lines per milliliter resolved.
     
  47. Mauro, I am not sure what you are looking at but it looks to me more like 15 microns/lp which is 67 lp/mm. I think you are being fooled by diffraction putting in more lines then are really there.
     
  48. So where does the 160 lp/mm come from? looking at the date sheet they only show the curve to around 65 lp/mm and at that point the MTF is already down to around 35% and dropping like a stone.
    Scott, look at the bottom right of page 7, where it says, "18. RESOLVING POWER, Chart Contrast 1.6:1 . . . . . 80 lines/mm, Chart Contrast 1000:1 . . . . . 160 lines/mm". Note that this says lines not line pairs. I do not know whether (1) that is an imprecise translation from Japanese usage to English usage, and they mean line pairs, or (2) that's what they really mean, lines. Obviously 80 lines/mm is 40 lp/mm and 160 lines/mm is 80 lp/mm.
    The MTF curve in section 21 does not appear to specify the contrast. However, as previously pointed out by Edward and me on more than one occasion, by the common criterion of 50% MTF response, you're down to that at about 45 lp/mm. The curve is not drawn past about 60 lp/mm (remember, it's a log scale), at which point the MTF response is down to about 35%. Even with a perfect lens, that is not going to record real-world image detail too well. Depending on the slope of the curve past that point, maybe there is some difference in density recorded at the 160 lp/mm point, but it can't be much, and only then with very (probably artificially) high-contrast subjects.
    Citing or testing resolution with 1000:1 contrast is very non-real-world. In old school terms, 1000:1 is the difference between Zone I and Zone XI--the extremes of what negative film might record with any real detail on either end. With transparency film like Velvia, you've got appreciable fewer zones to work with. In how many real-world pictorial subjects are many of the lines formed with that much contrast?
     
  49. Here Scott, I marked them for you:
    00WsRE-260655684.jpg
     
  50. Mauro, I'm with Scott--if you placed the ruler at the series of lines that you regard the smallest ones truly resolved, you have about 6.7 pairs in the space between what appears to be the 0 and the 10, representing 10/100 of a mm, so that would be 67 lp/mm. Note also that the contrast is low; if you break them down into hue, saturation, and value, the black line should have a value of 0, and the white line 255. But by my sampling, the average value of the "black" line is more like 42 and the "white" is 65--pretty low contrast.
    If you want to say you can see a little contrast on the next closer lines pairs, maybe just a tad; if you've created this little demonstrative correctly, that's at about 85 lp/mm. But the contrast is extremely low, and would almost certainly provide no real pictorial detail.
     
  51. Not much room for subjectivity.
     
  52. Dave, I can easily count lines to the left of the 150 lines/mm I marked in green. Velvia clearly resolves over 150 lines/mm in this scan.
    Not sure I understand the disagreement.
     
  53. Okay, wait a minute--Mauro says 160 lines per mm, Scott says 67 line pairs per mm--we are only disagreeing by a factor of 19%.
     
  54. Here is at 100% with some levels (to avoid any distortion on my previous image I posted at 200%).
    00WsRV-260656084.jpg
     
  55. By the way, I will admit that the fact the the lines are getting continuously farther apart as the chart proceeds to the right means that counting lines in all 10/100 of the mm lowers the number a bit. On the other hand, the ones at the right end of the ruler are clearly better resolved than the ones at the left end. So if you want to say that the scan demonstrates, oh, 70 lp/mm, that is, 140 lp/mm, or whatever, I won't quibble. So Mauro and Scott, I basically agree with both of you, and think you are misunderstanding each other with the "lines" versus "line pairs" issue, that is, one line pair is two lines.
     
  56. Mauro,
    In your scan the best I see is right around 8 pixels/line pair, if that image is really 8000 ppi then it means you are getting 1000 line pair/inch or around 40/mm. But at the same time I am reading on the scale what should be 0.10 mm as 0.20, did you scale the image up by a factor of 2? 40 line pair/mm seems too low, 80 would make more sense. In no way can I get 160 line pairs / mm out of your image.
     
  57. Scott, I am talking about lines per mm.
    160 lines per mm = 80 line pairs per mm.
     
  58. I'd like to see some one show me a digital sensor that can match the resolution of 4x5.
    Some years ago a comparison between 4x5 Velvia and a 39 MP P45 digital back on Luminous Landscape showed only a slight advantage to 4x5 film. Since then new digital backs like P65 have come out that can very well give 4x5 film a run for its money, but I am not aware of any tests with it.
     
  59. Saying this as a film user, Curtis, what the hell are you talking about?
    Are you going to use 4x5 for sports or other fast action? Superwides or long teles? 4x5 cameras are suited to certain things. They are not "the best". By your definition, why stop there? Why not 8X10, or Ultra Large Format?
    4x5 has always "destroyed" 35mm film, so where's the difference? It surpasses medium format as well, by virtue of larger physical size.
    What's "fair" about your comparison? Compare like to like. If I compared a digital at ISO 800 to Astia, would it be fair for me to complain about its noise? No more than it would be for me to complain about grain in high speed film compared to Astia.
    I don't use digital, except a little P&S for snapshots, but I would sure hate for anyone to get the impression that we film users are all as silly as your statement.
     
  60. Just how much resolution and detail does someone need? Even after around 6-8 MP how many photos would benefit form more resolution?
    With digital there is no real limit as to resolution, it is more a matter of how much is needed. But if resolution is your thing then 4x5 is pretty limited by today’s standards of what a high resolution photo is.
    Here is a 158 MPixel image that I took, it is not one of my highest resolution photos buy any means but even to it has way more than is needed.
    [​IMG]
    And a 100% crop shown below. [​IMG]
    But I find that going over around 20 MP to be a waste, in fact an 8 MP can be just fine in most cases, but really if it is raw detail you are after then digital is the way to go, IMO.
     
  61. I'm just impressed that Scott Wilson had a sunny day in coastal Oregon when he took that photo!
     
  62. C. Sharon , Jul 17, 2010; 06:01 p.m.
    I'd like to see some one show me a digital sensor that can match the resolution of 4x5.
    Some years ago a comparison between 4x5 Velvia and a 39 MP P45 digital back on Luminous Landscape showed only a slight advantage to 4x5 film. Since then new digital backs like P65 have come out that can very well give 4x5 film a run for its money, but I am not aware of any tests with it.​
    Nothing like needing to spend $30,000 to equal a $2 sheet of film ;-)
     
  63. Actually in over three decades of work I have never looked at any film through anything stronger than a loupe.
     
  64. david_henderson

    david_henderson www.photography001.com

    Nothing like needing to spend $30,000 to equal a $2 sheet of film ;-)​
    But if you wanted to take 15 000 photographs over the life of the back it might be worthwhile then.
    And you get to avoid buying, storing, carrying and processing film, and for many people, the cost and hassle of scanning. And you don't have to worry about ther space to store the negs/transparencies.
    Seems like a good deal to me if you're a volume user and you can raise $30 000.
     
  65. If only all this concentration and struggle about taking film and digital resolution to ridiculous heights were used for something truly productive, like developing CO2 capture structures near deposition points and deciding which path to take with clean energy and deploying it, I would take humanity more seriously....
     
  66. Scott,
    What are you shooting with?
     
  67. I was using a Canon 350D with the 50mm f/1.8. I was using a panoramic head and stiched with PTGui. It took 3 minutes to take the photos needed for the stitching, which really is not bad, but I have been reviewing what kind of resolution I really need.

    I started stitching not so much for higher resolution but rather a widerFOV, which it does great at. But the resolution part is very easy to get at the same time and can get a bit additive. However there are very few uses for an image that is over 20MP, and so now I have been taking more photos with my 28mm lens. With the 28mm lens it takes less then a minute to get my shots, in fact more like 45 seconds. The big advantage with using the 28mm lens is that I get a lot more DOF for the same f/number.
    Here is a photo I took, my wife and I run on this road in the morning and so I wanted to capture the feel of the road. I took 26 panoramic shoot along the road, of which this is one of.
    [​IMG]
    I can stitch this a number of ways but I like this one. I ended up with a nice image with 50 MP, the full image can be seen here
    50 MPixel image
    The photo was stitch from photos taken with my 28mm lens, I could have used my 50mm lens and gotten a lot more resolution but what would the point be.
    For myself it was never the resolution of film that I had a problem with it was a whole bunch of other issues. Trying to convince me that film is better because it can capture more detail is not going to get anywhere because detail is not the problem with most images.
     
  68. For myself it was never the resolution of film that I had a problem with it was a whole bunch of other issues. Trying to convince me that film is better because it can capture more detail is not going to get anywhere because detail is not the problem with most images.​
    Film or digital can only be better in context. For you digital is better because you do a lot with it in digital form. For me film is better because there is no computer involved.
     
  69. For me there was more computer work involved using film since I scanned my film and Ihave found scanned film needing a lot more post processing then digital. And the reason I scanned my film was for me I could get much better print with scanned film. The other reason for me to scan all the film that I care about is that just about all of my film is either fading or molding or both so if I want to be sure to have my photos in the future scanning is pretty much a must.
    If I were doing B/W things might be different but I had by fill of B/W in the 60s and 70s.
     
  70. Dave; any *REAL* honest lens test uses *PAIRS*; that is what one really looks at; ie a black and white PAIR of bars. This goes back to before WW2; when bull*hitting was not really acceptable.
    The same goes if one sells Shoes; socks; gloves; skis; it is understood by honest folks it means pairs. Ie Kilroy sold 5 shoes today; it means 5 pairs.
    Today spinelless BS rules; thus injecting a 2X factor is done by lay folks. Dumb folks; con artists; and lay folks love to use BS numbers; thus injecting a 2X factor is common today.
    It really has no place in research; ie marketing; cons.
    lay folks will boast they sold 10 shoes; or got 100 line per mm; when it is often just 5 pairs of shoes; or 50 line pairs per mm. Newbies and hucksters like big numbers; thus injecting a BS 2X factor is todays con.
    Few folks really get even 50 to 60 line pairs per mm on film in the real world with a sharp negative.
     
  71. Kelly,
    What you say about few folks getting even 50 or 60 line / mm may be true but it misses what the OP was addressing which was the limits of film resolution due to dye cloud size.
    I do agree that counting both the black and white lines is misleading however.

    I think the OP is a bit off on the dye cloud and that it is less then 10 microns, it is hard to tell but I would put it at closer to 6-8 microns. The problem with giving a size to something like a dye cloud is that it does not really have hard edges and there is a large variation from cloud to cloud. In the end trying to figure the limit of film resolution by looking at dye clouds is probably not the best way to go.
     
  72. The dye clouds must be martially smaller than 6, 8 or 10 microns to resolve 160 lines (80 line pairs) per millimeter.
    6 micros would be the maximum size the could be if I could magically align the bars on my tests with the dye clouds. Since that is obviously impossible on a random distribution; the dye clouds could only be 3-4 microns at most. (3 times smaller than the OP's assessment).
     
  73. This post is not a competition with digital, it is a discussion on Velvia dye clouds.
    In 2010, most landscape shooters use either MF film (6x7 Velvia or B&W) or DSLRs (10-20+ MP). Hence the vast majority of landscape pictures taken on film far out resolve the landscape pictures taken with digital.
    Film landscape shooters who choose 4x5 over 6x7 do it because of the movements and tonality, not because of resolution - since no one scans 4x5 at 8,000 dpi.
    On digital systems the most you can get today is 60MP at $40,000 from B&H. A lot less resolution than just MF film and at a joke of a price.
    It makes no sense to choose digital if the interest is resolution alone. But it does when convenience or fast shooting is needed.
    As an alternative, as Scott mentioned, one may use stitching (digital or film) for still subjects that allow for it.
     
  74. If the dots were square and uniform then a 10 micron square dot has its first null in the MTF curve right at 100 lp/mm. But it is closer to a circle and a circle with a diameter of 10 micron will have its first null at around 140 LP/mm. Due to a whole lot of other factors you are not going to see this limit when photographing but it does say that a 10 micron dye cloud is not at odd with just barely resolving 80 lp/mm. A 3 micson spot is far smaller then what is needed to resolve 80 lp/mm.
     
  75. Mauro Franic,
    You begin by saying "This post is not a competition with digital, it is a discussion on Velvia dye clouds."
    You then compare film to digital: e.g.: "A lot less resolution than just MF film and at a joke of a price."
     
  76. Will, my point was that an analysis of the dye clouds is far more interesting than the usual resolution of film vs digital (which I tested myself extensively). I also meant the capabilities of each medium are well understood - not a lot of room to see it as a competition.
     
  77. Scott, 3 microns gives you at least 2 clouds per line to resolve 160 lines/mm.
     
  78. Specifically to the OP's question:
    "
    I looked at Velvia 50 under a microscope today

    Thomas Lozinski , Jul 14, 2010; 04:31 p.m.
    At 100x magnification the grain or grain clusters? were about 10 nanometers (0.01mm) in diameter
    Counting each grain or cluster as a dot would give 2540 dpi and would give 24mm x 100dpmm x 36 x 100dpmm = 8.6 million dots (grains, grain clusters). I really don't think you can get more resolution than this out of the film"
    The answer is obviously a) the clouds are much smaller than measured by the OP, and b) of course one can get higher resolution then 8MP from Velvia 35mm.
     
  79. This is such a pointless argument. If you want a film vs. digital debate, then says so in the beginning! But since that's where you're going, you can see that film is better for landscapes & people for big prints:
    http://www.twinlenslife.com/2009/05/digital-vs-film-real-deal-nikon-d300-vs.html
    &
    http://www.kenrockwell.com/tech/filmdig.htm
    & this is from the Lightjet professional lab @ westcoast imaging. No digital outresolves 4x5 film from their printlabs.:http://www.westcoastimaging.com/wci/page/info/FAQ/faqprintlab.html
    [​IMG]
    purple is supeb, dark blue is excellent, orange is only fair........ Looks like nothing digital has to offer can outresolve film.
    To see this chart in its entirity, visit http://www.westcoastimaging.com/wci/page/info/FAQ/faqprintlab.html
    I've used westcoast for my prints from 35mm & Medium format & they are incredible. I love their canvas prints......
    As you can see 35mm is equivalent to a 15-22mp camera & 69mp can only match 6x6 film in the superb range. And nothing touches 8x10!
     
  80. Resolution is only a small part of what make a photograph, but if you really do want resolution then digital is going to win every time.
    4x5 is not used for much for resolution but rather to get an image that is free of grain.

    But if you really are a resolution junky then film is simply not going to give you your fix in this day and age.
    If you really want high resolution how about a 320 MP image, which is what you would get scanning a 4x5 film at 4000 ppi.
    http://sewcon.com/largephotos/pan1d 09-12-08.jpg
    But resolution simply losses meaning after a certain point. Whereas I think the op is off on the size of the cloud dyes and that due to this film can and does resolve more then what he has estimated how good an image looks is only somewhat determined but the resolutin captured.
     
  81. "Kodak Ektar 100 color negative film test ( updated d.d. 15-01-2009)"
    This test was shown at a website cited early in this thread. The results that a Sony A900 looks better than either Velvia or Ektar were obvious.
    However, the test was flawed. The test target was screen-printed, as shown in some of the downloads. Because neither the lines nor picture were solid, but screened, the fuzzy logic in the rather clever A900 converted them to what it thought the picture should look like. The film, on the other hand, had to deal with those pesky little white spaces in between bits of information on a screened print.
    That means to me that no conclusion can be drawn from the test. It neither proves nor disproves Ektar vs. Velvia vs. Sony A900.
    It does prove that the A900 provides good looking results, even if they aren't exactly what was photographed.
     
  82. "Kodak Ektar 100 color negative film test ( updated d.d. 15-01-2009)"
    This test was shown at a website cited early in this thread. The results that a Sony A900 looks better than either Velvia or Ektar were obvious.
    However, the test was flawed. The test target was screen-printed, as shown in some of the downloads. Because neither the lines nor picture were solid, but screened, the fuzzy logic in the rather clever A900 converted them to what it thought the picture should look like. The film, on the other hand, had to deal with those pesky little white spaces in between bits of information on a screened print.
    That means to me that no conclusion can be drawn from the test. It neither proves nor disproves Ektar vs. Velvia vs. Sony A900.
    It does prove that the A900 provides good looking results, even if they aren't exactly what was photographed."​
    I am the maker of that test you are referring too so negatively. To be honest, I have refrained from responding to most of these negative reactions I have seen passing by, since I think it is generally pointless to respond.
    I have to say though, that the thing that bugs me, is that most of the people that respond like this, haven't mostly ever done even a half decent test themselves and published it accordingly. In most cases, if anything is shown, it is badly executed, with photos not even taken from tripod... I am not saying my test didn't have some issues, it was a learning experience for me too, and I would definitely do some things differently next time. But to say that "the test has some flaws, and therefore no conclusions can be drawn at all" is just plain stupid. I think I have shown that there is still lots to learn, and from other responses I know quite a number of people agree with me.
    Yes, the dot screen printing pattern was an issue, but it was still a magnitude smaller than what the a900 and and films could truly reveal. Only the direct flatbed scan of the test chart, truly revealed it.
    "It does prove that the A900 provides good looking results, even if they aren't exactly what was photographed."​
    This remark made me laugh... I hit the release button, light enters the camera to expose the film or digital sensor, and now all of a sudden, the result "isn't what was photographed??!
    In what 10th dimension world are you living in that I am not?
    Sorry, but this is all about scale. Would you say the same thing if for example you photographed a model. You photograph her from a distance from feet to head up. Now you get in with a different lens, a macro lens, and photograph a small piece of her skin, revealing all the hairs on her arms, and even the skin pores.
    Would you now all of a sudden conclude that the first photograph of your lovely model "isn't what was photographed"?????????? because "it doesn't reveal all the hairy and blotchy unevenness" of her skin?
    Sorry, but this remark just doesn't make sense. Even if the screen pattern was close to be revealed, it still "is" what is photographed, and still does tell a lot about how all the contenders did in the test. In fact, the mere fact that all of the tested media were capable of revealing so much, is a compliment to all of them! People also don't realize how big the actual test chart was, it is NOT some small post card, but a giant 60x90 cm print.
    If you think you can do better, why not do it and publish it properly... after two years, I am still waiting for a real good substitute for my test, not only executed well, but published and documented accordingly up to a level that I did. I haven't seen it...
     
  83. If you do a test, at least follow the scientific method. One sample isn't going to cut it. You need a control group, and variables. I think we can all agree that digital is better than film @ high ISO, unless you want a lot of grain.
     
  84. Marco Boeringa,
    I found your comparison test for Ektar vs. Velvia vs. Portra vs. the A900 quite useful.
    J Marrs,
    In that test, I see a control (the flatbed scan), and four experimental groups. I think Marco Boeringa demonstrated a distinct difference in apparent resolution between the groups, and a distinct difference in apparent noise between groups. I encourage you to repeat the experiment, or to design and conduct a better one.
    Everyone else,
    If anyone reading this thread is interested, the test is located here.
    Will
     
  85. J Marrs,
    Just what are you talking about with your control group and variables, the test was simply to compare a number of films and the A900 and I believe it did a good job at that. A control does not entry into this kind of testing.
     
  86. "If you think you can do better, why not do it and publish it properly... after two years, I am still waiting for a real good substitute for my test, not only executed well, but published and documented accordingly up to a level that I did."
    I have.
    "I haven't seen it..."
    I'll take your word for it.
    My test was a little different. I did Velvia 50 (original) , Ektar 25 (a little over the pull date even back then), Reala and the then top-o'- the- line Canon digital (with less MP than an A900). Back then I used a microscope (Yes, only on the film), a 4000PPI Nikon scanner , a 2900PPI Nikon scanner, bought 8000PPI drum scans and borrowed the local camera store's Canon digital demo. Lenses were my Contax/Carl Zeiss 135mm, F:2.8 at around F:8.0 and my Contax/Carl Zeiss 50mm, F:1.4. The Canon had the shop's best 135mm Canon lens, I think F:2.0 and their Canon 50mm, F:1.4.
    I used both a Kodak test target (screen printed) similar to yours, and a USAF 1951 2'x3' test chart from Edmond Scientific. I also shot painted graphics on a truck about 200 yards away. I used a sturdy, heavy wooden (absorbs ground vibration better than metal) tripod with a weight hung from the middle post.
    My results and conclusions:
    1. The Ektar out resolved the Velvia 50 by a slim margin. The Velvia out resolved the Reala a fair amount. The Reala out resolved the Canon a fair amount. The Velvia out resolved the Canon a LOT. The Velvia had the smallest grain of the films.
    2. The best looking result on the computer screen was the Canon for the screen printed target, with Reala the worst. On the USAF chart and the real world tests, Velvia on the drum edged out the Ektar but more to grain issues. Both Velvia and Ektar had more resolution than a 4000PPI Nikon as was seen on the 8000PPI drum. The drum did nothing for Reala except produce a file 4x the Nikon 4000PPI. Detail increased on the Reala between the 2900PPi and 4000PPI Nikons.
    3. Digital prints were made of cuts from each as if the total scan would be 5'x7.5' on an Epson rated at 1440/2880 DPI input at 360PPI (it can take several dots to represent a pixel). Velvia off the drum looked best, the Canon looked the worst. There was a LOT more detail with the Velvia and Ektar than the Canon digital. Up-sizing was bicubic as Genuine Fractals was not available to me as I had thought it would be at the time.
    No, I do not have the results ready to post at your very command as I am almost 3000 miles from home and will be for some time. The results have been posted on the net previously. Some may still be there. I know some are not as I did not re-up my site "paid membership".
    I'll stick to my statement:
    "This test was shown at a website cited early in this thread. The results that a Sony A900 looks better than either Velvia or Ektar were obvious.
    However, the test was flawed. The test target was screen-printed, as shown in some of the downloads. Because neither the lines nor picture were solid, but screened, the fuzzy logic in the rather clever A900 converted them to what it thought the picture should look like. The film, on the other hand, had to deal with those pesky little white spaces in between bits of information on a screened print.
    That means to me that no conclusion can be drawn from the test. It neither proves nor disproves Ektar vs. Velvia vs. Sony A900."
    .........and further state that results from a screen printed test target do not prove resolution but can make computer generated digital camera output look pretty good.
    But, being more precise in my use of the English language I'll revise my comment:
    "It does prove that the A900 provides good looking results, even if they aren't exactly what was photographed." to say:
    It does prove that the A900 provides good looking results, even if does not show exactly what was photographed.
    P.S.
    I think you did us all a service doing your test and sharing the results and I thank you.
     
  87. This discussion beggars belief.
     
  88. Sorry Art if I was a bit harsh on you yesterday. To be honest, it was not my best day...
    We're probably not going to fully agree on the usefulness of the test I did, but that doesn't matter to me. Point is, I have at least made a serious attempt to be thorough and put a lot of work in it, and I don't like to be "dismissed" based on remarks made in "thin air" as quite often happens. Or based on some uncontrollable mythical "expert knowledge" that some people claim to have... Like saying "Oh, I heard two decades ago from a now deceased person at company X that lens Y can reach 200 lp/mm resolution with film Z. They have published it in an internal report that isn't accessible..." Yeh, sure!
    Anyway, I would still love to see better documented results if anyone has them. Based on some of the other stuff I have seen passing by, I think my results were quite in line with others.
    1. The Ektar out resolved the Velvia 50 by a slim margin.​
    I am not surprised by this. If you look at my results (which is Velvia 100F), the results of Ektar and Velvia are quite close too. I can imagine a flip between them in some cases.
    In addition, Velvia 50 and Velvia 100F are two distinct films. I also shot a role of Velvia 50 after I published the test, but didn't include it as I found that the scans results didn't have finer grain than Velvia 100F (the F variants of Fuji films use the latest "grain technology" according to Fuji). In fact, according to the official Fuji film datasheets for Velvia 50 and Velvia 100F, Velvia 100F even has a marginally smaller RMS granularity, indicating a slightly finer grain:
    RMS granularity for Velvia 50 (RVP50): 9
    http://www.fujifilm.com/products/professional_films/pdf/velvia_50_datasheet.pdf
    RMS granularity for Velvia 100f (RVP100F): 8
    http://www.fujifilm.com/products/professional_films/pdf/velvia_100f_datasheet.pdf
    This discussion beggars belief.​
    ;-), yes, we should all be out shooting film, instead of discussing it till it's dead...
     
  89. As usual people are testing the scanner when they think they are testing film.....
    Velvia outresolves Ektar as well as a 4000dpi scanner.
    This is a tiny little crop from a test scanned with a Coolscan 9000 at 100%.
    http://shutterclick.smugmug.com/Other/Ektar-TMX-Velvia/6616619_YJEwK#471880876_V8LEa-O-LB
    Under the microscope (and also with the 8000dpi scans I posted), one can easily observe that Velvia outresolves the scanner. Ektar and the scanner have very similar limits.
     
  90. "Sorry Art if I was a bit harsh on you yesterday. To be honest, it was not my best day..."
    A strong and healthy defense based upon hard work is a good thing. I certainly took no offense. I did however want to defend my experiment and work done.
    "Point is, I have at least made a serious attempt to be thorough and put a lot of work in it"
    You certainly have. Additionally, one thing it did point out is that digital cameras do tend to make irregular surfaces look more pleasing to the eye. This is a benefit to many digital shooters.
    "1. The Ektar out resolved the Velvia 50 by a slim margin."
    That is because it was the old Ektar 25 vs. the old Velvia 50. Comparing slides shot with a good lens in the real world and looking at detail in the distance, unscientifically, I feel the new Velvia 50 out-resolves the current Ektar 100. Even with the old Ektar vs. the old Velvia, microscopic comparison of resolution was hampered by the larger grain of the Ektar 25. At the point of my test, the Ektar 25 had both been frozen and was probably a couple years past the pull date. Ektar 25 has been thought to be one of the few films that is negatively altered by freezing. Freezing is supposed to increase its grain, among other things. I had neither the equipment nor inclination to test the Ektar 25 vs. the Velvia 50 when I had both films current and refrigerated, but unfrozen. Perhaps someone out there has done another test.
    "and I don't like to be "dismissed" based on remarks made in "thin air" as quite often happens"
    I'll second that.
    Again, I thank you for your well-thought-out and meaningful test. You, of course, did do your own work, use some thoughtfulness, maintain consistency and standards, and came to a rational decision. Although I disagree with a part of your conclusions, no one could rightfully say that you did not materially and unselfishly add to our knowledge base. Again, I thank you. In my mind, you join the ranks of contributors like Les Sarile, et.al. who contribute meaningfully to photonet and the enthusiast as well as the professional community.
     
  91. As usual people are testing the scanner when they think they are testing film.....​
    That is the problem with nearly all digital vs. film comparisons. They are really digital vs. scanner tests. A fair test would be a good print made from a fully digital process compared to a good print made from a fully film and optical print process.
    Another problem with these test is that they are often biased towards the reviewers personal preferences.
     
  92. david_henderson

    david_henderson www.photography001.com

    It depends what you're trying to find out. For most people, making prints from film will involve scanning somewhere in the process. So there's every point IMO to assess a print from a film scan vs a print direct from a digital photograph on the same paper and using the same printer type.
    Just as there's every point in comparing prints made the same way and to the same spec using different scanners ( I never can tell what a good scan looks like on a screen).
    And comparing prints from the same scan ( or digital photograph) using different labs and printer/paper combinations
    and so on.
     
  93. syd

    syd

    I'm still shooting film ... 100% Velvia, scanning it and loving it. No test required for that ...
     
  94. Best response yet Simon. I use Velvia and Astia in MF and 4x5. Don't need a test to see I like the look of films better than a lot of digital work.....and 35mm is fine for virtually grain free 16x24.
     
  95. In the end I think each person needs to do their own testing. In 2005 I was questioning the need to continue to shoot film so I did some tests to see if there would be cases where the film would be a clear winning in image quality. For my cameras, lenses and scanner I could get more detail with film of high contrast subjects, but not by a huge amount and the other issues with film made its overall image quality not as good as what I was getting using my digital camera. These tests to help me decide if there was a point for me to keep shooting film, there was not. But other people with other gear really need to test for themselves.

    I have also done tests with friends where we go out and shoot the same scenes, I shooting digital and them shooting film, and then we compare the prints. This has helped them get an idea of what they would get moving from film to digital, given the film camera, film, lens and scanner they are using.
     
  96. Scanners - like the Coolscans and others, don't have bayer issue like DSLR sensors. You should consider this in your response to my first question about your 12MP digianything.
    It's evident from your own test samples that 12 MP DSLRs (i.e. the D2x) out resolve desktop scanned 35mm film when it comes to low contrast, color detail. I've demonstrated that the 18 MP 7D can out resolve 35mm Velvia, scanned on an Imacon, on low contrast color detail. So what "Bayer issues" are you referring to in relation to resolution?
     
  97. OP, as Edward indicated 35mm Velvia resolves 160 lpmm (this is over 4,000 true dpi) on a high contrast target. This is materially (about twice as much) higher than any 12mp camera for high contrast and fine detail.
    Come on Mauro, you know better than this. Velvia only records 160 lpmm on 1000:1 lab tests. You never, ever find 1000:1 contrast in fine detail in the real world. You would have to shoot the sun through a picket fence to achieve those kinds of lab conditions. Note that 1000:1 is greater than Velvia's dynamic range, which means you get no tonality, just black and white in those tests.
    Velvia's resolution is roughly 80 lpmm for real world high contrast detail. Velvia on an Imacon or drum scanner will just barely out resolve a D700 on high contrast detail, but that doesn't mean it will necessarily look better. It would take a lot of work to make the Velvia scan as sharp and noise free as the D700 shot. (Then again, it can take a lot of work to give a D700 shot the same color as Velvia, which may be preferred by the photographer.) As I've demonstrated in past threads, an 18 MP 7D RAW shot is a pretty good match for the very best 35mm Velvia scans and exceeds Velvia in low contrast resolution, while pretty much matching it on high contrast resolution.
     
  98. Just out of curiosity, are there test charts for "medium contrast resolution"? Something like 18% grey bars on a white background and a black background? That would be a helpful standard, wouldn't it, since you'd be pretty much guaranteed to run into that sort of contrast in the real world most of the time?
     
  99. Here we got out first 35mm slide scanner back in 1989. Our first 2 pro flatbed cost 3 grand each in the early 1990's. I have Nikon and canon 2700 and 4000 dpi film scanners for 35mm; plus two Nikon 9000 MF units that are 4000 dpi.
    I have tested lenses with USAF charts for over 40 years.
    If I look that swarm of the publics "sharp" 35mm stuff to scan; about zero is in the 100 line pair per mm league; it is more like say 50 to 60.
    Few if anybody records 100 like pairs per mm on film in pictorial useage; unless they are a total bull shitter.
    One does have some rare lens tests that did record over 100 line pairs per mm on film; if one looks back and cherry picks data; and uses goosed test conditions; ie 1:1000 test targets; Panatomic-X; granite blocks; timed lights; *AND* one brackets by 1/3 stops and cherry picks the best data.
    A film scanner is going to low pass details; depending on the real useable dpi of the device. Use a dump flatbed and one how has 24 to 32 line pairs per mm. Use a 4000 dpi film scanner and a zillion dpi reference etched glass negative; and one gets sub 80 line pair per mm results; ie normally 70 to 75 numbers.
    This whole subject is old.
     
  100. Interesting discussion. Sorry I'm late to the party, but after reading through the posts, these are my impressions:
    1. Mauro's combined image of the microscope scan and 8000dpi scan of velvia does suggest roughly 160lpmm (*not* 160lp/mm, but l/mm) is conceivable for Velvia 50.
    2. Shooting test charts gives an advantage to digital images, where the processing involved in getting from the bayer to the actual image favours black and white images with sharp lines.
    3. I haven't seen a conclusive test so far which shows all of the detail film has to offer. Ideally, I'd like to see a Heidelberg Tango scan of various 35mm film shot of an organic target with infinite detail (i.e. a landscape) versus, say, a D3X or similar camera, versus medium format (as the reference).
    I would love to do this comparison, but I don't have access to any of those bits of equipment!! Any takers?
     

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