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Everything posted by tupp

  1. As others have suggested, the term "density" has a specific meaning in regards to film emulsions. I think that the property of "thickness" that you seek is mostly derived from color depth (not bit depth). Color depth in digital imaging is a product of resolution and bit depth (COLOR DEPTH = RESOLUTION x BIT DEPTH). The fact that resolution affects color depth in digital images becomes apparent when one considers chroma subsampling. Chroma subsampling (4:2:2, 4:2:0, etc.) reduces the color resolution and makes the images look "thinner" and "brittle," as you described. Film emulsions don't have chroma subsampling -- essentially film renders red, green and blue at equal resolutions. Almost all color emulsions have separate layers sensitive to blue, green and red. There is almost never a separate luminosity layer, unlike Bayer sensors or RGBW sensors which essentially have luminosity pixels. So, if you want to approximate the "thickness" of film, a good start would be to shoot 4:4:4 or raw, or shoot with a camera that uses an RGB striped sensor (some CCD cameras) or that utilizes a Foveon sensor. You could also use an RGB, three-sensor camera.
  2. No need for ignorant bigotry. The notion that camera people got work in the 1980s by owning cameras couldn't be further from the truth. "Hiring for gear" didn't happen in a big way until digital cameras appeared, especially the over-hyped ones -- a lot of newbie kids got work from owning an early RED or Alexa. To this day, clueless producers still demand RED. Back in 1980's (and prior), the camera gear was almost always rented if it was a 16mm or 35mm shoot. Sure, there were a few who owned a Bolex or a CP-16 or 16S, or even an NPR with decent glass, but it was not common. Owning such a camera had little bearing on getting work, as the folks who originated productions back then were usually savvy pros who understood the value of hiring someone who actually knew what they were doing. In addition, camera rentals were a standard line-item in the budget. Of course, there was also video production, and Ikegami and Sony were the most sought-after brands by camera people in that decade. Likewise, not too many individuals owned hi-end video cameras, although a small production company might have one or two. Today, any idiot who talks a good game can get a digital camera and an NLE and succeed by making passable videos. However, 99% of the digital shooters today couldn't reliably load a 100' daylight spool.
  3. Yes. It might be best to run the leads outside of the adapter/speedbooster, and epoxy or hot-melt-glue the switch to the adapter housing. By the way, the pictured dip switch is tiny.
  4. Why not just put a switch inline on the "hot" power lead of the adapter instead of powering with an external source? That way, OP can just enable and disable the electronics by merely flicking the switch. Incidentally, here is a small dip switch that might work:
  5. The paragraph reads: "I have repeatedly suggested that it is not the sensor size itself that produces general differences in format looks -- it is the optics designed for a format size that produce general differences in format looks." Again, you somehow need to get that point through your head. Perhaps you should merely address my points individually and give a reasonable counter argument each one. Unless, of course, you cannot give a reasonable counter argument.
  6. This should read: "Once again, I have repeatedly suggested that it is NOT the sensor size itself that produces general differences in format looks..."
  7. You certainly don't need to address each of my points, and, indeed, you have avoided almost all of them. In regards to the your parenthetical insinuation, I would never claim that the number of individuals who agree/disagree with one's point has any bearing on the validity of that point. However, please note how this poster unequivocally agrees with me on the problems inherent in your comparison test, saying, "I certainly can see what you're talking about in the areas you've highlighted. It's very clear." In regards to my not providing evidence, again, are you referring to evidence other than all the photos, video links, and references that I have already provided in this thread, which you have yet to directly address? Additionally, you have misconstrued (perhaps willfully) my point regarding sensor size. I have continually maintained in this thread that it is the optics designed for a format size -- not the format size itself -- that produce general differences in format looks. The paper that you linked does address points made in this thread, but a lot of the paper discusses properties which are irrelevant to DOF equivalency, as I pointed out in my previous post. Interestingly, the paper frequently suggests that larger format optics have capabilities lacking in optics for smaller formats, which is what I and others have asserted. Not sure how you missed those statements in the paper that you referenced. Regardless, I have more than once linked Shane Hurlbut's example of an exact focus match between two different lenses made from two different manufacturers. So, there should be no problem getting such a close DOF/focus match from other lenses with the proper methods. Once again, I have repeatedly suggested that it is the sensor size itself that produces general differences in format looks -- it is the optics designed for a format size that produce general differences in format looks. Somehow, you need to get that point through your head. Your thoughtful consideration and open-mindedness is admirable.
  8. Well, I certainly appreciate your thoroughly addressing each one of my points and your giving a reasonable explanation of why you disagree. You mean, do I have any evidence other than all the photos, video links, and references that I have already provided in this thread, which you have largely avoided?
  9. It's not a good read on this at all, as most of the information given is irrelevant. Furthermore, many of the conclusions of this paper are dubious. How is "sensor quantum efficiency" relevant to optical equivalency? How is "read noise" relevant to optical equivalency? Lens aberrations are absolutely relevant to optical equivalency and DOF/focus. According to Brian Caldwell, aberrations can affect DOF and lenses for larger formats generally have fewer aberrations. Hence, the refractive optics of larger formats generally influence DOF differently than lenses for smaller formats. Keep in mind that the DOF/equivalency formulas do not account for any effects of refractive optical elements, yet optical elements can affect DOF. Again, this property is not really relevant to optical equivalency and DOF/focus. This property is not really relevant to optical equivalency and DOF/focus. Only one of these six factors (aberrations) that you and the paper present are relevant to optical equivalency and DOF/focus. So, why is this paper quotee/linked? On the other hand, here is a choice sentence from he paper that immediately follows your excerpt: There are other similar passages in that paper suggesting differences in image quality between different sized formats. If the intention of quoting/linking that paper was to assert that it is difficult to get an exact match between two different lenses made by two different manufactures, I once again direct you to Shane Hurlbut's test in which he compared two different lenses made by two very different manufacturers (Panasonic and Voigtlander), that exactly matched in regards to the softness/bokeh of the background, with only a slight difference in exposure/color. So, a more exact match can be achieved than what we have seen so far in "equivalency tests." In addition, we can compare the actual DOF, instead of seeing how closely one can match an arbitrarily soft background set at some arbitrary distance, while relying on lens aperture markings and inaccurate math entries.
  10. It is doubtful that any of the equivalency tests presented so would be accepted by "scientists" as a valid DOF/equivalency comparison. In regards to your claim in this thread that it is impossible to exactly match the focus between two lenses of the same focal length made for the same format from different manufacturers, I have already linked a comparison conducted by Shane Hurlbut in which the focus matches precisely -- much more exactly than any equivalency comparison presented here. So, we probably can get a significantly closer match in a DOF equivalency test than what we have seen so far. This is false, as exemplified by the Shane Hurlbut test mentioned above. That might work, especially if one likes to do things the hard way. Not sure what the point is regarding low element numbers.
  11. The reason why we don't have a proper test of DOF equivalency from still photographers (nor from cinematographers) likely doesn't involve involve the number of variables. The true reason would probably require some philosophizing. It probably would not be wise to shoot DOF/equivalency comparisons using the same emulsion for different formats. The smaller format on the same emulsion could appear to have a lower resolution, more softness and more grain, which would invalidate the results. On the other hand, digital formats lend themselves perfectly to such a test, as they have standardized resolutions. So, a Super16 full HD camera will have the same digital resolution as an 8"x10" full HD camera. Yep. Focal reducers tend to transfer the qualities of the larger format lens to the image of the smaller format. Thanks for the link! For the benefit of those who are unfamiliar with in-camera corrections for chromatic aberration, vignetting, barrel/pincushion distortion, etc., such features have been implemented in digital cameras for a long time, and these corrections are not unique to Fuji cameras.
  12. Thanks! Very helpful! So, the 2.5K raw mode @ 2.35:1 vignettes with 16mm lenses? Does the 2.8K mode vignette with Super 16 lenses?
  13. What is the crop factor of these modes (what lens formats match the cropping)?
  14. That's a good point, and such in-camera "lens correction" features have existed for a long time and are not unique to Fuji cameras. The primary in-camera feature that might affect DOF tests would be the chromatic aberration correction. In-camera reductions of barrel distortion, vignetting, and local color changes (from frame center to edge) are less involved in DOF/focus. A few things come into play here. Firstly, Fuji is no slouch in regards to lenses. Their optics are known for exceptional quality, and I would bet that most Fuji lenses today need very little digital, in-camera corrections. In regards to comparing your APS-C Fuji zooms to FF Canon, Pentax, Minolta primes and Nikkor zooms, keep in mind that when you crop into the image circle of those FF lenses, you are throwing away resolving power and lens character. A good focal reducer will transfer most of the FF resolution and the lens character to the smaller format. Also, it's not surprising that chromatic aberration appears on some of your non-Fuji lenses that are modern, as camera manufacturers have a tendency these days to rely more on digital correction over optical correction. So, of course, if your X-T3 isn't correcting the chromatic aberration on the non-Fuji lenses, that would further explain the difference. Keep in mind that these minor in-camera features will not change the DOF nor focus to make APS-C lenses (especially zooms) render images like those from 8"x10" lenses.
  15. I think that this ffmpeg command will create a new file that runs all the frames at 120fps without transcoding: ffmpeg -r 120 -i original30fps_file.MOV 120fpsoutput_file.mov If it doesn't transcode, it should make the 120fps copy quickly. Also, it would be easy to make a script based on this command that would batch convert a bunch of files. Of course, you could always convert the frames to run at 120fps in an NLE.
  16. That 40mm Kipon f0.85 is designed for APS-C, so it should be slightly closer in look to larger formats than a lens designed for M4/3. Also, as I have mentioned, cropping into a lenses image circle will change the look and make the image softer. However, I found examples of that lens wide with a open aperture on an APS-C sensor. Although that lens is not an equivalent focal length to the lens of the 8"x10" image I linked earlier in this thread, it yields comparably shallow DOF, so it should give us a rough idea of how lenses for smaller formats behave in such shallow DOF scenarios. Here is one example. Of course, the Kipon APS-C lens looks softer and more mushy wide open, with the 8"x10" lens exhibiting more resolving power and a crisp image. Also, the plane of focus with the 8"x10" lens seems more solid and well defined than that of the APS-C lens. The APS-C lens additionally suffers from chromatic aberration (remember, Caldwell confirmed that lenses for smaller formats are more prone to aberrations). I think that these differences between these two lenses are common to most lenses made for lager and smaller formats, and that the such results will largely be consistent in any proper DOF/format comparisons that might follow. I too would like to see a proper DOF/look comparison done between larger and smaller formats.
  17. We haven't directly touched on speedboosters in this thread, but there have been other discussions about how speedboosters/focal reducers are involved in format looks. The adapter/crop issue has been addressed in this thread. The format looks in question do not involve sensor size, per se.
  18. What makes a format necessary are what someone considers to be desirable qualities. We are discussing the desirable qualites of larger formats vs. smaller formats -- which involves FF.
  19. No. You are mistaken. You need to more carefully read what I have said. I usually attribute differences in equivalency comparisons to failures of the testers. It might be helpful for you to actually read what I wrote. How is this relevant? By the way, if you use mirrorless cameras with shallow mounts, a tilt/shift adapter works with many lenses. So, are you saying that larger formats have qualities that are lacking in smaller formats? 600mm 8"x10" lens is more like an 80mm FF lens (or like a 40mm M4/3 lens). There are a few 80mm FF lenses. There would likely be a difference between the look of two formats with such a narrow focal length and with the apertures set for a shallow DOF. Well, that would actually qualify as a look inherent in a larger format that is impossible in a smaller format, wouldn't it? You really need to read what I wrote in regards to optics and sensor size. The failure to get a match is usually due to tester mistakes. In addition, all of the testers so far were not actually testing DOF. Incidentally, in regards to your earlier claim about it being impossible to get an exact match with two lenses that have the same focal length and that are designed for the same format, here is that very comparison by Shane Hurlbut. It looks like an exact DOF/focus match to me, but the exposure is slightly different (likely due to a difference in lens transmission). So, exact focus matches are possible.
  20. Well, not exactly. If you use a S16 lens on a 4"x5" sensor, you will likely see substantial vignetting that won't appear with the same lens on a S16 sensor. The image inside the vignette probably will appear softer, as the pixels on the 4"x5" sensor are likely coarser. Likewise, if one applies a S16 crop inside the image circle of a lens made for 4"x5", most of the lines of resolution will be thrown away, and the image will appear much softer (which can affect the appearance of the DOF) than using that same lens on a 4"x5" sensor. That's not too difficult. Earlier in this thread, I picked the S16, M4/3 and 8"x10" formats, and I found several manufactured lenses for those formats that gave around a 98% match on the equivalence calculator that was linked earlier in this thread. That's a good start, and most of the other variables can be adjusted slightly without suffering invalid results. In regards to knowing the exact focal length when it changes after focusing on the subject, as long as the focal lengths remain in a nominal range there really is no problem, as one can make adjust the aperture so that the results match more closely (as I have already explained in this thread). This is where you (along with the legions of equivalency testers that precede you) and I depart. There is absolutely no need to stand on the formality of getting the numbers to exactly match the figures dictated by the DOF/equivalency formula, and trying to do so will only lead to difficulty and mismatched, invalid results. The aperture markings on lenses are not accurate enough (and T-stops are useless for such a test). Also, aperture markings don't account for the change in focal length when the lens is adjusted to put the subject in critical focus. If you wanted to get a precise number match to the DOF formula, you would have to measure the exact focal length when focused and the exact aperture diameter, which is somewhat challenging considering there is no tangible focal point marking on lenses and considering that the aperture is usually inside the lens. Trying to get the numbers to precisely match the DOF/equivalency formula is a fools errand. On the other hand, there is nothing wrong with setting up the test with two camera/lens combinations that match as closely as possible, and then merely adjusting the aperture ring on one of the cameras until the two DOF ranges match by eye. If the adjusted aperture reads a little off from where the DOF/equivalency formula says it should be, simply make a note of that adjustment and include that note in the test report. That's unnecessary, and you would only need to crop one of the images if you want to exactly match the frames. No. If you use T-stops markings, you are making an even bigger error than if you just rely on the accuracy of F-stop markings. The aperture markings on the lens are inaccurate and mostly irrelevant. Well, if you like to do things the hard way as prescribed in your method, you will have a tough time and will unlikely get valid results. I agree that your method might not work in a lifetime. I would think that this point of this exercise was obvilus by now -- to demonstrate similarities and/or differences between optics made for different formats. Good for you! There are tests that got a close enough match with the equipment. However, they suffered the maladies that afflict most other tests: they didn't show the delineation of the DOF limits; they used wide angle lenses and/or deep DOF; they used a zoom lens; they had camera sharpening enabled; and, of course, they didn't adjust the aperture by eye to match the DOF.
  21. I'll just repeat what has been mentioned in this thread. The lenses for the smaller formats have to use larger apertures to match the DOF of larger format lenses. So, if one is shooting large format with shallow DOF (as in the above photo), matching that DOF with a with a smaller format lens will require its aperture to be wide open, which not only affects the overall sharpness (As you surmised), but it can also produce a difference in the relative sharpness between center and edges of the frame. This characteristic with the smaller format lessens as the aperture is reduced. The above 8"x10" photo was shot with a roughly 600mm lens (not sure on the aperture), and the closet lens match that I could find in a smaller format is the Nokton 42.5mm f0.95 for M4/3. Here is a test of that lens set at f.0.95 that not quite as close/tight as the above photo, but it gives a rough idea of how it might behave close and wide open. It doesn't seem as sharp wide open as it does at smaller apertures, and, unfortunately, the DOF isn't quite shallow enough to match that of the above 8"x10" lens. In addition, at wider apertures, there generally seems to be a faster transition from sharp to soft at the rear DOF limit on lenses made for larger formats. This quality might relate to why the plane of focus seems more solid, more well-defined and flatter on larger formats. Also, the softness/bokeh outside of the DOF seems cleaner and less mushy. Here is a photo shot with an 8x10 camera that shows that shows a solid, flat focus plane (although the lens appears to be swung slightly to the right), with the subject nicely separating from the clean and not too mushy background.
  22. I don't have any conclusions in regards to larger formats vs. smaller formats other than the ones I have mentioned in this thread and in other threads. Larger formats don't usually suffer from diffraction with deep DOF, hence the f/64 club.
  23. Most of the test parameters are given in the second half of this post from earlier in this thread. The format related properties are inherent in their optics, but the format and its optics are married to each other in regards to the look/sharpness. I agree that a controlled test should reveal general differences in optics for made for different formats. No. The problem with the tests are not their degree of rigor -- the problem is that every DOF test presented so far completely misses the point of what it is that is being tested. If one is testing DOF, it is sort of necessary to show the actual DOF. Instead, almost all such tests so far have merely shown the subject and an arbitrarily soft background at some arbitrary distance. Here is the typical set-up that we see in these comparisons; camera >> AIR >> sharp subject >> AIR >> soft background The limits of the DOF invariably are located in the "AIR" where there is no object nor surface visible to show the location nor the transitional character of those important limits. So, instead of testing the DOF, these comparisons actually just show how closely the tester can match the soft background using math along with the aperture markings on the lens. Usually, these tests also suffer other significant mistakes, such as in-camera sharpening, using zoom lenses, using wide lenses with deep DOF, etc. Additionally, the "soft background" in most of these tests is usually a wall or some other obstruction, beyond which no detail nor focus falloff is visible. Obviously, the foreground limit of DOF is important in DOF tests, because that limit is a major element that determines the DOF. In addition, the transitional characteristic of the foreground limit and the character of the softness beyond that frontA limit are both crucial to a lot of cinematography. For instance, consider any focus rack from far to near (or vice versa). When the camera is focused on the distant subject, the look of the soft near subject is determined by the DOF. In regards to Yedlin's test images showing the same elements characteristics as those in the 8"x10" photo that I linked above, there is one important and conspicuous difference -- the 8"x10" image shows the rear DOF limit and its distinctive transitional character quite clearly, while the rear DOF limit in Yedlin's shots are lost in the air. And, again, Yedlin used wider lenses with a deeper DOF. Not so with my linked image. Yes. The parameters are: Use dramatically different sized formats (with their corresponding optics); Use a continuously visible surface (preferably ruled) or a row of uniform objects that starts far in front of the subject and that recedes far behind the subject; Use narrow lenses; Use a shallow DOF; First set the DOF of the smaller format, then match by eye the DOF of the larger format.
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