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#21
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FF sensors: is 80MP needed?
frederick wrote:
Roger N. Clark (change username to rnclark) wrote: Digital also has much greater dynamic range. How dare you keep saying that - when believing the reverse is the raison d'ętre for the quaint obsession some have for 35mm. ;-) |
#22
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And again, digital vs (LF) film...
[A complimentary Cc of this posting was sent to
Roger N. Clark (change username to rnclark) ], who wrote in article : Irrelevant. You are discussing lens+sensor vs lens+film. I'm discussing lens+sensor vs lens+ideal_sensor. Theory is fine, but you must consider all factors. One can never consider all factors. It is important to consider *key* factors - of course. One factor you have not considered, [...] is not just resolution, but [...] Since all I was considering was resolution, it is not surprising I did not consider other factors. ;-) (Especially since I already addressed "other factors" in my other posts; here I concentrated on some "new" experiments.) Digital has a much higher signal-to-noise ratio Such a blank statement is definitely wrong; you mean the same exposition, and it is not applicable to my comparison. E.g, with the current technology digital will give much worse noise than film if the exposition of digital is 20x smaller than of film ;-). And note that this is quite probably holds when you compare LF film to FF digital (but I do not remember the details of the exposition you used...) - count number of photons per "pixel" (I mean square with size determined by the MTF curve). ... that greatly influences perceived image detail. Film has practically no noise when correctly exposed with aperture f/32 - or much smaller f-number. Digital also has much greater dynamic range. IMO, this remains to be proven yet (though I suspect that the proof *will* support your claim - I just *have not seen* it). Your investigation is very interesting, but, IMO, it completely missed the point. Essentially, you measured the noise of 6um square of film vs 8um square of semiconductor. So, film's noise *at these extremely high spacial frequencies* turns out to be much more than digital sensors'; fine. But, as you probably saw it in many posts about your experiments, it is the noise at much lower spacial frequencies what many people consider the measure of dynamic range. So how one could measure "true dynamic range"? Essentially, one cannot separate dynamic range from resolution; e.g., in each exposition zone, one could measure the S/N ratio at different spacial frequencies, and find at which frequency S/N ratio goes above 3 (or some other reasonable number). One gets a curve of (thus defined) spacial resolution per degree of underexposition; *this curve*, IMO, is the measure of dynamic range. Again: I agree with you that such an investigation will *most probably* give film much lower mark than digital sensor - but 10x20in film is practical, and digital is not. BTW, the question I addressed in my initial posting is also related to this: for which f-numbers this advantage of film will disappear, since FF digital sensor may behave as well as HUGE area of film. Thanks, Ilya |
#23
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FF sensors: is 80MP needed?
[A complimentary Cc of this posting was sent to
frederick ], who wrote in article 1160974662.417746@ftpsrv1: Would you like to qualify your "lack of being impressed" by some objective measure of your own Already the second paragraph contains complete BS: And with that smaller focal length is around a 2.5 times increase in available depth of field. Anyone knows that switching formats does not bring any change in DoF - if one WANTS to produce identical images, one can. Different formats produce non-identical results only because of different "effective MP count", and lens quality at the used f-stop (well, QE may also enter the picture, e.g., when you compare film to digital). You just use f-stop "proportional" to the formfactor, and everything else comes out to be identical. Let me repeat: The physical laws of scaling are the following: to produce the same image from N times smaller sensor (linearly) one needs to: a) have the same count of pixels; b) have the same QE; c) have the same readout noise; d) have the same full well; e) have the same exposure time; f) use N times higher aperture (measured as an F-number, e.g., 1/45); g) have the same "quality" of the lens (e.g, measured as quotient of actual MTF of the lens to MTF of diffraction-limited lens) Hope this helps, Ilya |
#24
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FF sensors: is 80MP needed?
"Scott W" wrote in message
oups.com... Matt Clara wrote: I haven't used 10 mp, so I don't know, but I suspect it would lack in one way, and that's the same way the 6-8 mp cameras do: upon enlargement they begin to break down rather quickly. To me this speaks to overall levels of infomation present in the two mediums, but it could be any number of reasons. Enlargement, of course, isn't the reason digital is eclipsing 35mm, and even there it's good enough for some purposes. I still shoot my formals as well as some select other shots with medium-format film precisely because it can be blown up poster-size with little detraction to the image, provided it's a sharp, well exposed negative, of course. This seems like a bit of bait and switch to me, you seem to claim that 35mm film is better then an 8 MP DSLR but then you say you are using MF film. Clearly MF will easily beat an 8 MP DLSR but I have yet to see a color image from 35mm film that beats a 8 MP DSLR and the vast majority of 35mm film scans fall far short of a 8 MP DSLR. You're right Scott, I should have mentioned that I have shot 35mm right along side digital, plus I used to shoot nothing but 35mm, and 35mm blows up better. I also think I get more keepers with 35mm, and fewer exposure problems, but the ability to see those problems with the digital is priceless and the fact that I don't have to pay for 15 rolls of development and prints isn't priceless, I can see a very real savings there, though it's traded for lots of time in front of a computer. As for your inability to see that 35mm beats digital in most forms today, I suggest you simply don't have the experience there, or you would. And I'm not talking about scans of 35mm--you don't have to scan it to get the job done, see. -- Regards, Matt Clara www.mattclara.com |
#25
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FF sensors: is 80MP needed?
Matt Clara wrote:
And I'm not talking about scans of 35mm--you don't have to scan it to get the job done, see. But scanning is about the only way we have to compare, unless you want to come to Hawaii with your prints. If you are trying to say that optical prints show more detail then it should be easy to scan the optical print. The best that I have seen by far is a scan Max Perl did and whereas the 35mm shot showed more detail then an 8 MP camera when printed out they were about the same quality due to the grain in the film scan. Since I would not do a workflow that does not have the image in a digital form at some point if it can't be scanned it is not of much value to me. And since I have yet to see anyone demonstrate that a workflow that does not scan the film can produce a better image when when you scan film I am not going to take that on faith. Scott |
#26
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FF sensors: is 80MP needed?
David J. Littleboy wrote:
"Greg "_"" wrote: If you want to use monochrome film - a material that has incomparably inconvenient performance compared with even the cheap digital cameras that they now sell at the supermarket Right smirk :^ yawn. 25 iso monochrome.... zzzzzz Reasonably few B&W shooting photographers shoot 25 asa BW film on a consistent, none I know personally. That's because most of them have been discontinued. Panatomic X and Tech Pan are history. (I think there's still an Agfa film in production, though.) Panatomic-X is the reason I hate 35mm. At 11x14, Plus-X in 645 looks way better than Panatomic X in 35mm, and is two stops faster. ISO 25 gets real painful when you want to use either a red filter or a polarizer. Nowadays, TMX 100 is close to what the ISO 25 films used to be in terms of grain and resolution, although some people complain they don't like its tonal rendition. TMX 100 in 6x7 will edge out the 5D, though. About 40 or so years ago over a period of a couple of years I used micro-neg pan developed in Dilute FX1a developer (designed by Geoffrey W. Crawley and published in BJP) rated at 8asa and although it was slow the results were pleasing but not for action. The grain could hardly be seen. -- Delete l to reply. |
#27
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FF sensors: is 80MP needed?
Scott W wrote:
Matt Clara wrote: And I'm not talking about scans of 35mm--you don't have to scan it to get the job done, see. But scanning is about the only way we have to compare, unless you want to come to Hawaii with your prints. If you are trying to say that optical prints show more detail then it should be easy to scan the optical print. The best that I have seen by far is a scan Max Perl did and whereas the 35mm shot showed more detail then an 8 MP camera when printed out they were about the same quality due to the grain in the film scan. Since I would not do a workflow that does not have the image in a digital form at some point if it can't be scanned it is not of much value to me. And since I have yet to see anyone demonstrate that a workflow that does not scan the film can produce a better image when when you scan film I am not going to take that on faith. Scott I have had plenty of experience with 35mm optical process prints from negative and transparency - and have a big portfolio of larger (10x8)prints that I can easily compare. Most of the larger prints I made from 35mm used Fuji iso 50 and Cibachrome. I always carried two slr bodies, one loaded with iso50 transparency for enlargements, the other loaded with iso 200 negative film because iso 50 is practically useless for handheld shooting in less than ideal light, yet ideal light is seldom what you want for taking interesting pictures. Scanned 35mm negative film printed with light-jet leaves the optical process cibachrome prints in the dust for reproducing detail. Inkjet prints direct from digital look better again, and are almost infinitely more convenient. I really couldn't care less about technical arguments - how the picture looks is the most important factor. A few years ago, I realised that snapshots taken from an inexpensive pocket sized 4mp P&S digital were practically as good as what I could get with iso200 35mm. 35mm film is dead - there is no point at all now that dslr cameras are affordable. |
#28
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FF sensors: is 80MP needed?
Ilya Zakharevich wrote:
[A complimentary Cc of this posting was sent to frederick ], who wrote in article 1160974662.417746@ftpsrv1: Would you like to qualify your "lack of being impressed" by some objective measure of your own Already the second paragraph contains complete BS: And with that smaller focal length is around a 2.5 times increase in available depth of field. Anyone knows that switching formats does not bring any change in DoF - if one WANTS to produce identical images, one can. Only when maximum DOF is the objective. Not when shallow DOF is sought. Different formats produce non-identical results only because of different "effective MP count", and lens quality at the used f-stop (well, QE may also enter the picture, e.g., when you compare film to digital). You just use f-stop "proportional" to the formfactor, and everything else comes out to be identical. You have quoted selectively: "The only downside to my new system is working with depth of field. On my 4x5 Linhof, I have a focusing gauge that allows me to quickly determine the optimum f stop for each situation. With the Mamiya and the zoom lenses, this is much harder to determine. On the plus side, a composition that required a 200mm on the 4x5 needs only an 80mm for the P45 sensor. And with that smaller focal length is around a 2.5 times increase in available depth of field." That comment "available depth of field" doesn't have to mean as you assume it could. |
#29
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FF sensors: is 80MP needed?
[A complimentary Cc of this posting was sent to
frederick ], who wrote in article 1161030861.1650@ftpsrv1: Anyone knows that switching formats does not bring any change in DoF - if one WANTS to produce identical images, one can. Only when maximum DOF is the objective. Not when shallow DOF is sought. When true, this is a part of what I said: one needs the same "lens quality at the used f-stop". When/If you can open 35mm-formfactor lens to the same entry pupil as the LF lens (with the same "optical build quality"), they create identical images (only scaled differently) - same diffraction, "same" abberations, same DoF. Of course, this "If/when" is rarely possible... Different formats produce non-identical results only because of different "effective MP count", and lens quality at the used f-stop (well, QE may also enter the picture, e.g., when you compare film to digital). You just use f-stop "proportional" to the formfactor, and everything else comes out to be identical. You have quoted selectively: "The only downside to my new system is working with depth of field. On my 4x5 Linhof, I have a focusing gauge that allows me to quickly determine the optimum f stop for each situation. With the Mamiya and the zoom lenses, this is much harder to determine. On the plus side, a composition that required a 200mm on the 4x5 needs only an 80mm for the P45 sensor. And with that smaller focal length is around a 2.5 times increase in available depth of field." That comment "available depth of field" doesn't have to mean as you assume it could. I do not agree with you. Read: "on the plus side"; obviously, he thinks that with smaller formfactor he will have larger depth of field. (This is only true if he would use the same f-stop; but when you convert to a more open f-stop needed to get the same diffraction [measured in the subject space, i.e., in angular units], one gets exactly the same DoF...) Yours, Ilya |
#30
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FF sensors: is 80MP needed?
Ilya Zakharevich wrote:
[A complimentary Cc of this posting was sent to frederick ], who wrote in article 1161030861.1650@ftpsrv1: Anyone knows that switching formats does not bring any change in DoF - if one WANTS to produce identical images, one can. Only when maximum DOF is the objective. Not when shallow DOF is sought. When true, this is a part of what I said: one needs the same "lens quality at the used f-stop". When/If you can open 35mm-formfactor lens to the same entry pupil as the LF lens (with the same "optical build quality"), they create identical images (only scaled differently) - same diffraction, "same" abberations, same DoF. Of course, this "If/when" is rarely possible... Different formats produce non-identical results only because of different "effective MP count", and lens quality at the used f-stop (well, QE may also enter the picture, e.g., when you compare film to digital). You just use f-stop "proportional" to the formfactor, and everything else comes out to be identical. You have quoted selectively: "The only downside to my new system is working with depth of field. On my 4x5 Linhof, I have a focusing gauge that allows me to quickly determine the optimum f stop for each situation. With the Mamiya and the zoom lenses, this is much harder to determine. On the plus side, a composition that required a 200mm on the 4x5 needs only an 80mm for the P45 sensor. And with that smaller focal length is around a 2.5 times increase in available depth of field." That comment "available depth of field" doesn't have to mean as you assume it could. I do not agree with you. Read: "on the plus side"; obviously, he thinks that with smaller formfactor he will have larger depth of field. (This is only true if he would use the same f-stop; but when you convert to a more open f-stop needed to get the same diffraction [measured in the subject space, i.e., in angular units], one gets exactly the same DoF...) Yours, Ilya Yes - but he also gets increased DOF at the same f-stop , same FOV, and same shutter speed. For sure a big drawback for large format is slow shutter speeds, as although you can use a tripod, you can't stop things from moving in the frame. Ultimately you are of course correct - but it may mean that you can't take a photo with even a moving snail in the frame ;-) |
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