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#1
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Nikon D800; it's going to be fascinating
To see (if the rumours are right) which model sells more, the one with an
AA filter and the one without. If enough of the ones without sell, this will be a radical change in cameras. |
#2
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Nikon D800; it's going to be fascinating
"Rich" wrote in message ... To see (if the rumours are right) which model sells more, the one with an AA filter and the one without. If enough of the ones without sell, this will be a radical change in cameras. Not to open a can of worms here, but isn't anti-aliasing a good thing? Even with a slight decrease in sharpness, I'd think it would be beneficial. |
#3
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Nikon D800; it's going to be fascinating
"Tim Conway" wrote in message
... "Rich" wrote in message ... To see (if the rumours are right) which model sells more, the one with an AA filter and the one without. If enough of the ones without sell, this will be a radical change in cameras. Not to open a can of worms here, but isn't anti-aliasing a good thing? Even with a slight decrease in sharpness, I'd think it would be beneficial. Yes, of course it is, but: - if you use lenses with no significant response above the Nyquist frequency, then there's nothing for the AA filter to remove. I.e. with lenses which aren't the sharpest it doesn't matter. Put another way, if the camera is 36 MP but the lens only 18 MP, there may be no need for AA filtering. - optical AA filters are imperfect, so there is a design compromise between little filtering and some moiré, and too much filtering and loss of sharpness (i.e. loss of high spatial frequencies). Different folk will have different tastes and choose different degrees of AA filtering. - there are some folk who appear to be confused about sharpness, judging by phrases like "razor sharp" and the gross over-sharpening you see on some people's images. Perhaps they are still using CRT monitors which have become out-of-focus with age? G Cheers, David |
#4
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Nikon D800; it's going to be fascinating
"David J Taylor" wrote: "Tim Conway" wrote in message ... "Rich" wrote in message ... To see (if the rumours are right) which model sells more, the one with an AA filter and the one without. If enough of the ones without sell, this will be a radical change in cameras. Not to open a can of worms here, but isn't anti-aliasing a good thing? Even with a slight decrease in sharpness, I'd think it would be beneficial. Yes, of course it is, but: - if you use lenses with no significant response above the Nyquist frequency, then there's nothing for the AA filter to remove. I.e. with lenses which aren't the sharpest it doesn't matter. Put another way, if the camera is 36 MP but the lens only 18 MP, there may be no need for AA filtering. Bad idea, bad math. Sure, AA filters are a kludge (they shift (double) the image in two directions), but they are still a much closer approximation to a brick wall filter than lens infelicities, or even diffraction. AA filters leave very good contrast in place at just a small fraction of Nyquist below said frequency, which means that pretty much all detail that can be correctly rendered actually is*. Lens resolution falloff is gradual, so if you have a lens bad enough that it doesn't cause aliasing, then it's going to have uninspired contrast at 1/2 Nyquist. So your 36MP camera is acting as a poor 9MP camera if your lens is bad enough to not have aliasing problems. *: In real life, Bayer images look really really good. The idea that there's a problem is really quite silly. -- David J. Littleboy Tokyo, Japan - optical AA filters are imperfect, so there is a design compromise between little filtering and some moiré, and too much filtering and loss of sharpness (i.e. loss of high spatial frequencies). Different folk will have different tastes and choose different degrees of AA filtering. - there are some folk who appear to be confused about sharpness, judging by phrases like "razor sharp" and the gross over-sharpening you see on some people's images. Perhaps they are still using CRT monitors which have become out-of-focus with age? G Cheers, David |
#5
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Nikon D800; it's going to be fascinating
On Tue, 27 Dec 2011 09:22:35 +0900, "David J. Littleboy"
wrote: : : "David J Taylor" wrote: : "Tim Conway" wrote in message : ... : : "Rich" wrote in message : ... : To see (if the rumours are right) which model sells more, the one with : an : AA filter and the one without. If enough of the ones without sell, this : will be a radical change in cameras. : : Not to open a can of worms here, but isn't anti-aliasing a good thing? : Even with a slight decrease in sharpness, I'd think it would be : beneficial. : : Yes, of course it is, but: : : - if you use lenses with no significant response above the Nyquist : frequency, then there's nothing for the AA filter to remove. I.e. with : lenses which aren't the sharpest it doesn't matter. Put another way, if : the camera is 36 MP but the lens only 18 MP, there may be no need for AA : filtering. : : Bad idea, bad math. Sure, AA filters are a kludge (they shift (double) the : image in two directions), but they are still a much closer approximation to : a brick wall filter than lens infelicities, or even diffraction. AA filters : leave very good contrast in place at just a small fraction of Nyquist below : said frequency, which means that pretty much all detail that can be : correctly rendered actually is*. Lens resolution falloff is gradual, so if : you have a lens bad enough that it doesn't cause aliasing, then it's going : to have uninspired contrast at 1/2 Nyquist. So your 36MP camera is acting as : a poor 9MP camera if your lens is bad enough to not have aliasing problems. : : *: In real life, Bayer images look really really good. The idea that there's : a problem is really quite silly. David's argument sounds convincing, but so do all arguments to someone as profoundly ignorant of the underlying physics as I am. So I, a Canonian with no dog in this hunt, propose to wait and see whether more people send their D800's back to have an AA filter installed than send theirs back to have the AA filter removed. If so, I guess David wins the argument. If not, I guess the purists who dislike AA filters win. If everybody sticks with what they bought, it's a tie. Anybody got a better way of settling it? ;^) Bob |
#6
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Nikon D800; it's going to be fascinating
"David J. Littleboy" wrote in message
... [] - if you use lenses with no significant response above the Nyquist frequency, then there's nothing for the AA filter to remove. I.e. with lenses which aren't the sharpest it doesn't matter. Put another way, if the camera is 36 MP but the lens only 18 MP, there may be no need for AA filtering. Bad idea, bad math. Sure, AA filters are a kludge (they shift (double) the image in two directions), but they are still a much closer approximation to a brick wall filter than lens infelicities, or even diffraction. AA filters leave very good contrast in place at just a small fraction of Nyquist below said frequency, which means that pretty much all detail that can be correctly rendered actually is*. Lens resolution falloff is gradual, so if you have a lens bad enough that it doesn't cause aliasing, then it's going to have uninspired contrast at 1/2 Nyquist. So your 36MP camera is acting as a poor 9MP camera if your lens is bad enough to not have aliasing problems. *: In real life, Bayer images look really really good. The idea that there's a problem is really quite silly. -- David J. Littleboy David, Please note the words "may be". Yes, of course it depends on the absolute lens MTF etc., and it was obviously not intended to be a rigorous exposition. While lens MTF fall-off is certainly not the same shape as an anti-alias filter, it varies in shape between different lenses and at different zoom and aperture settings. Indeed, a "9 MP lens" would be even less likely to benefit from an anti-alias filter on a 36 MP sensor. BTW: I was /not/ intending to use a 2:1 linear, and 4:1 area comparison, so the maths is correct. Poor lenses need less AA filtering, and the degradation from an AA filter will be less with such lenses. It begs the question: why would anyone buy a very high resolution sensor, and yet use lower quality lenses? I can think of one answer - supposing you were buying in the NEX range. You may want the features of the NEX-7, but may not need the resolution, and you may be content with the smaller, lighter, cheaper and lower-quality lenses. Because you want the features of that particular model, you are stuck with the higher-resolution sensor it comes with. Cheers, David T |
#7
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Nikon D800; it's going to be fascinating
"David J Taylor" wrote: "David J. Littleboy" wrote in message ... [] - if you use lenses with no significant response above the Nyquist frequency, then there's nothing for the AA filter to remove. I.e. with lenses which aren't the sharpest it doesn't matter. Put another way, if the camera is 36 MP but the lens only 18 MP, there may be no need for AA filtering. Bad idea, bad math. Sure, AA filters are a kludge (they shift (double) the image in two directions), but they are still a much closer approximation to a brick wall filter than lens infelicities, or even diffraction. AA filters leave very good contrast in place at just a small fraction of Nyquist below said frequency, which means that pretty much all detail that can be correctly rendered actually is*. Lens resolution falloff is gradual, so if you have a lens bad enough that it doesn't cause aliasing, then it's going to have uninspired contrast at 1/2 Nyquist. So your 36MP camera is acting as a poor 9MP camera if your lens is bad enough to not have aliasing problems. *: In real life, Bayer images look really really good. The idea that there's a problem is really quite silly. David, Please note the words "may be". Yes, of course it depends on the absolute lens MTF etc., and it was obviously not intended to be a rigorous exposition. Rigor isn't the problem: the idea is _in principle_ wrong. For very good, but easily explained informally, reasons: gradual falloff vs. sharp falloff. While lens MTF fall-off is certainly not the same shape as an anti-alias filter, it varies in shape between different lenses and at different zoom and aperture settings. Not really. Even poor lenses have long tails of low response out to quite high frequencies. -- David J. Littleboy Tokyo, Japan |
#8
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Nikon D800; it's going to be fascinating
Rigor isn't the problem: the idea is _in principle_ wrong. For very
good, but easily explained informally, reasons: gradual falloff vs. sharp falloff. While lens MTF fall-off is certainly not the same shape as an anti-alias filter, it varies in shape between different lenses and at different zoom and aperture settings. Not really. Even poor lenses have long tails of low response out to quite high frequencies. -- David J. Littleboy If the response of the lens is low, then the amount of aliasing visible in the final image will be low as well, and it follows that poorer lenses have less need of a strong anti-alias filter then good lenses. It's the net MTF above Nyquist which matters. Having said that I, for one, would not be choosing a camera with no anti-alias filter. Cheers, David |
#9
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Nikon D800; it's going to be fascinating
"David J. Littleboy" wrote in
: "David J Taylor" wrote: "Tim Conway" wrote in message ... "Rich" wrote in message ... To see (if the rumours are right) which model sells more, the one with an AA filter and the one without. If enough of the ones without sell, this will be a radical change in cameras. Not to open a can of worms here, but isn't anti-aliasing a good thing? Even with a slight decrease in sharpness, I'd think it would be beneficial. Yes, of course it is, but: - if you use lenses with no significant response above the Nyquist frequency, then there's nothing for the AA filter to remove. I.e. with lenses which aren't the sharpest it doesn't matter. Put another way, if the camera is 36 MP but the lens only 18 MP, there may be no need for AA filtering. Bad idea, bad math. Sure, AA filters are a kludge (they shift (double) the image in two directions), but they are still a much closer approximation to a brick wall filter than lens infelicities, or even diffraction. AA filters leave very good contrast in place at just a small fraction of Nyquist below said frequency, which means that pretty much all detail that can be correctly rendered actually is*. Lens resolution falloff is gradual, so if you have a lens bad enough that it doesn't cause aliasing, then it's going to have uninspired contrast at 1/2 Nyquist. So your 36MP camera is acting as a poor 9MP camera if your lens is bad enough to not have aliasing problems. *: In real life, Bayer images look really really good. The idea that there's a problem is really quite silly. Only a problem is loss of resolution, which IS visible, even with a D200 as conversion of said camera proved that. I want to see the results of this new AA-less camera versus the AA camera with a good lens. For those terrified of the potential for interference with fine, repeating details, they should stick with the AA filter. |
#10
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Nikon D800; it's going to be fascinating
"Rich" wrote in message
... [] Only a problem is loss of resolution, which IS visible, even with a D200 as conversion of said camera proved that. I want to see the results of this new AA-less camera versus the AA camera with a good lens. For those terrified of the potential for interference with fine, repeating details, they should stick with the AA filter. Noticeable resolution drop is perhaps not surprising on a 10 MP camera, but I thought we were talking nearer 36 MP? David |
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