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#11
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EOS 7D and resolution
Oops. Sorry for the double post. Damn news client said it failed to
send, but it didn't, obviously. Colin D. |
#12
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EOS 7D and resolution
ColinD wrote:
A chain being only as strong as the weakest link, I feel that resolution is already being limited by most lenses outside their best apertures at lower than the present megapixels. (I don't think you'll get a noticeably better image from a wide open EF 50mm f/1.4 at 18MPix than at 8MPix + sensible upscaling (e.g. Lanczos scaling) where needed, for a drastic example.) Even if the lens cannot equal the sensor for resolution, the image will still be better than with fewer pixels. Sure, if you use arbitrary wrong definitions for 'better'. The resultant resolution is always a function of both lens and sensor. I've pointed this out several times in the past. Point out as much as you want. Doesn't mean it's true or relevant. The maximum resolution obtainable in practical photographic work is limited both by the camera lens and by the film/sensor. The formula often used to predict the resolution of a camera original is: See how you went from "better image" to a "*prediction* of resolution"? By your logic infinitely small sensor sizes, unable to capture even a single photon, would produce 'better' images than any other sensor with the same lens. Even you should be able to see several catches with that. Your claim, *as it stands*, is obviously wrong. And misses a very important word to be relevant to practical use, "noticeable" or "visible". 1/Rt2 = 1/Rs2 + 1/RL2 (Higgins, G.C.Appl. Opt. 3, v.1, 9, Jan 1964) Ah, yes, a formula from the good old days a decade before the first digital image sensor, back when higher resolution meant slower films with finer, less notable grain. As you can see, system resolution is not just lens resolution alone. I can see that you probably don't understand 'better' or 'noticeable' --- or what tinier pixels do unless you raise the technology in between. Maybe you should look at the independent lens test sites and see if your formula comes up with the right answers as you test the same lenses at the same format size against different sensor resolutions ... -Wolfgang |
#13
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EOS 7D and resolution
On Wed, 30 Sep 2009 13:27:15 +0200, Wolfgang Weisselberg
wrote: ColinD wrote: A chain being only as strong as the weakest link, I feel that resolution is already being limited by most lenses outside their best apertures at lower than the present megapixels. (I don't think you'll get a noticeably better image from a wide open EF 50mm f/1.4 at 18MPix than at 8MPix + sensible upscaling (e.g. Lanczos scaling) where needed, for a drastic example.) Even if the lens cannot equal the sensor for resolution, the image will still be better than with fewer pixels. Sure, if you use arbitrary wrong definitions for 'better'. The resultant resolution is always a function of both lens and sensor. I've pointed this out several times in the past. Point out as much as you want. Doesn't mean it's true or relevant. The maximum resolution obtainable in practical photographic work is limited both by the camera lens and by the film/sensor. The formula often used to predict the resolution of a camera original is: See how you went from "better image" to a "*prediction* of resolution"? By your logic infinitely small sensor sizes, unable to capture even a single photon, would produce 'better' images than any other sensor with the same lens. Even you should be able to see several catches with that. Your claim, *as it stands*, is obviously wrong. And misses a very important word to be relevant to practical use, "noticeable" or "visible". 1/Rt2 = 1/Rs2 + 1/RL2 (Higgins, G.C.Appl. Opt. 3, v.1, 9, Jan 1964) Ah, yes, a formula from the good old days a decade before the first digital image sensor, back when higher resolution meant slower films with finer, less notable grain. As you can see, system resolution is not just lens resolution alone. I can see that you probably don't understand 'better' or 'noticeable' --- or what tinier pixels do unless you raise the technology in between. Maybe you should look at the independent lens test sites and see if your formula comes up with the right answers as you test the same lenses at the same format size against different sensor resolutions ... What would that show? Wally Wally |
#14
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EOS 7D and resolution
Wolfgang Weisselberg wrote:
ColinD wrote: A chain being only as strong as the weakest link, I feel that resolution is already being limited by most lenses outside their best apertures at lower than the present megapixels. (I don't think you'll get a noticeably better image from a wide open EF 50mm f/1.4 at 18MPix than at 8MPix + sensible upscaling (e.g. Lanczos scaling) where needed, for a drastic example.) Even if the lens cannot equal the sensor for resolution, the image will still be better than with fewer pixels. Sure, if you use arbitrary wrong definitions for 'better'. The resultant resolution is always a function of both lens and sensor. I've pointed this out several times in the past. Point out as much as you want. Doesn't mean it's true or relevant. The maximum resolution obtainable in practical photographic work is limited both by the camera lens and by the film/sensor. The formula often used to predict the resolution of a camera original is: See how you went from "better image" to a "*prediction* of resolution"? By your logic infinitely small sensor sizes, unable to capture even a single photon, would produce 'better' images than any other sensor with the same lens. Even you should be able to see several catches with that. Your claim, *as it stands*, is obviously wrong. And misses a very important word to be relevant to practical use, "noticeable" or "visible". 1/Rt2 = 1/Rs2 + 1/RL2 (Higgins, G.C.Appl. Opt. 3, v.1, 9, Jan 1964) Ah, yes, a formula from the good old days a decade before the first digital image sensor, back when higher resolution meant slower films with finer, less notable grain. As you can see, system resolution is not just lens resolution alone. I can see that you probably don't understand 'better' or 'noticeable' --- or what tinier pixels do unless you raise the technology in between. Maybe you should look at the independent lens test sites and see if your formula comes up with the right answers as you test the same lenses at the same format size against different sensor resolutions ... -Wolfgang Well, if one removes the sarcasm from your reply, there's practically nothing left of it. *Of course* resolution is a function of both film/sensor and the lens. If it were not so, then every lens would deliver an image dependent only on lens resolution, regardless of sensor resolution, a conclusion that is patently incorrect. Whether you can 'notice' a 'visible' difference depends on the manner in which you view the image, but that is irrelevant; a difference will exist whether you can see it with naked eye or not. And the age of the formula is totally irrelevant also - or has E=MC^2 passed it's use-by date as well? -- Colin D. |
#15
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EOS 7D and resolution
ColinD wrote:
I see you still misuse other peoples' domains and email addresses. Well, if one removes the sarcasm from your reply, there's practically nothing left of it. Sure, if you relabel valid criticism --- like pointing out your asocial misuse of the email address you knowingly falsely claim as yours --- as sarcasm ... *Of course* resolution is a function of both film/sensor and the lens. Obviously. Even R = min(R_S, R_L) is a function of both sensor and lens. Now go away with your strawmen and *prove* your 'equation'. You can find some data at photozone.de --- you should be able to correlate the observed resolutions for the same lens/focal length/aperture settings at different sensor resolutions. But of course that would be work and it would turn out that your claim is neither as clear-cut nor as correct as you'd like it to be. Whether you can 'notice' a 'visible' difference depends on the manner in which you view the image, but that is irrelevant; a difference will exist whether you can see it with naked eye or not. A difference that has no impact has no relevance. Differences that cannot be seen are thus irrelevant to visual arts. Of course, that truth will be labled 'sarcasm' by you. And the age of the formula is totally irrelevant also - or has E=MC^2 passed it's use-by date as well? Not yet(!). It may yet end as phlogiston did, or be outdated Newton's laws of gravitation --- the future will tell. -Wolfgang |
#16
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EOS 7D and resolution
Wally wrote:
On Wed, 30 Sep 2009 13:27:15 +0200, Wolfgang Weisselberg Maybe you should look at the independent lens test sites and see if your formula comes up with the right answers as you test the same lenses at the same format size against different sensor resolutions ... What would that show? It would show if the formula was correct. Spot checks say it's off. -Wolfgang |
#17
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EOS 7D and resolution
On Thu, 1 Oct 2009 15:09:46 +0200, Wolfgang Weisselberg
wrote: Wally wrote: On Wed, 30 Sep 2009 13:27:15 +0200, Wolfgang Weisselberg Maybe you should look at the independent lens test sites and see if your formula comes up with the right answers as you test the same lenses at the same format size against different sensor resolutions ... What would that show? It would show if the formula was correct. Spot checks say it's off. You are not very convincing! Wally |
#18
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EOS 7D and resolution
Wally wrote:
On Thu, 1 Oct 2009 15:09:46 +0200, Wolfgang Weisselberg What would that show? It would show if the formula was correct. Spot checks say it's off. You are not very convincing! Tell me, what would convince you? -Wolfgang |
#19
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EOS 7D and resolution
Sorry for the late reply. My ISP discontinued their usenet server
(probably because they don't want to tarnish their image by storing copyright infringements and under-aged models and such). Rich wrote in : Was that posted online somewhere? Someone linked to it in DPReview, from rapidshare, but I don't think it is there anymore. There was an 8-column periodic cycle of about 18 14-bit ADU, IIRC, in the blackframe. The same pattern repeated in other frames, at other ISOs. It is something that could be fixed if Canon just put a self-calibration routine in the camera, accessible by the user. Even if it couldn't be calibrated in the electronics by the user, the RAW data could easily be re-written to remove the pattern. I have a 7D pre-ordered from Amazon. I feel like I am at a casino, gambling on IQ, because of Canon's poor QC. I hate having to erode my relationship with a vendor to keep returning things to get a good copy. Canon should bear the brunt of all their sloppiness - then they wouldn't be sloppy for very long. |
#20
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EOS 7D and resolution
Wolfgang Weisselberg wrote in
: It seems a lot of people are, uhm, a bit megapixel crazy. Other than the increased storage requirements and processing speed, what is crazy about resolution? You really don't have enough pixels (in terms of proper sampling) until it takes about 3 pixels exclusive to transition a sharp black/white subject transient, with your optics. Historical digital cameras image poorly, and if you print at any good size or crop, the pixel structure becomes immediately apparent, and all its artifacts. A chain being only as strong as the weakest link, I feel that resolution is already being limited by most lenses outside their best apertures at lower than the present megapixels. (I don't think you'll get a noticeably better image from a wide open EF 50mm f/1.4 at 18MPix than at 8MPix + sensible upscaling (e.g. Lanczos scaling) where needed, for a drastic example.) Hardly. The noise is finer, and there is less alisasing in the 18MP version. Low-MP images are fragile things; they only capture some of the detail at the highest image frequencies they capture, as it depends on luck of pixel and subject alignment, and then what you do capture at those highest frequencies are prone to loss with any king of geometric manipulation, like rotation, perspective correction, CA correction, etc. And that Canon may have concluded that that's where the future is, at least in the near term. Your vigorously defensive reaction syggests to me that you may secretly suspect that I'm right. ;^) Canon has concluded that they need to sell cameras and to sell cameras they need to compete in features and marketing numbers. Megapixel record numbers belong there. Except for some specimen-variable vertical banding patterns at low ISOs on the 7D (invisible for so-called "proper exposures", for the most part), the 7D has the best IQ of any APS-C to date, while having the highest pixel density as well. In fact, I expect the 7D to be more usable than my 5D2 in low-key images at extremely high ISOs, because the 7D is very lacking in line noise, especially horizontal banding with nyquist component, which causes color lines (the vertical is lower- frequency and is more of a luminance noise). If suddenly a serious part of the camera buyers(!) would decide cameras needed to look like puppys and smell of burned toast --- well, Canon would be stupid to not offer them exactly that. As for *me*, that's not where *my* future lies, yes. Sometimes the populous is right by accident, which is the case, IMO, with pixel resolution. |
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