09-30-2010, 11:57 AM
[quote name='genotypewriter' timestamp='1285827097' post='3380']
I don't think things add up like that. Which ever is causing the more blur will be the one that's causing all the blur. An AA-filter tries to create a blur around roughly every 3 photosites and so you can think of this as a blur the size of 3 photosites. If the blur from diffraction is less than the radius of 3 photosites, you won't see the diffraction. If the blur from diffraction is greater than the size of 3 photosizes, say 5 photosizes big, then you will only see a blur of 5 photosites big... not 5+3=8.
Umm again not sure if you should go there so easily. Diffraction limitation depends on the size of the photosites. But does that mean a 14MP Bayer sensor and a 14MP Foveon with equal sized photosites resolve the same detail (resolution)? The short answer is no.
All that aside, I've also heard people talk about diffraction occurring at the photosite-level on Foveon sensors because of the depth the light has to travel to reach the bottom most layer. So the bottom-most layer, red, will be getting less light than the rest and the top and (mainly) the middle layer will be contaminated with diffracted red light.
If anyone's wondering which side I'm on... I like Foveon for how it tries to work and for most of its results. But Bayer CFA tends to give the most usable output <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />
GTW
[/quote]
Those people have really weird ideas. The recording of diffraction is basically recording light that should have been intended for neighbouring pixels. I do not see how getting less light in the red layer would mean light intended for that pixel would end up in neighbouring pixels!
I really fail to see how diffraction softening could happen on pixel level, they are using a wrong term to describe something different.
Point remains: The foveon sensors will not be affected worse by diffraction. Diffraction is ONLY in the projected image, and the AA-filter-less sampling willnot get a more soft picture than an AA-filtered one.
Which brings us back to the reason Sigma images are "sharper"... due to the refusal to use AA-filters. If you remove the AA-filter from a Bayer CFA sensor, you will get the same kind of sharpness. Liked by some, disliked by those in the know (that is why most camera manufacturers put AA-filters in front).
Did you know, by the way, that the AA-filters are very expensive to develop and produce? They cost about the same as the sensor itself costs.
I don't think things add up like that. Which ever is causing the more blur will be the one that's causing all the blur. An AA-filter tries to create a blur around roughly every 3 photosites and so you can think of this as a blur the size of 3 photosites. If the blur from diffraction is less than the radius of 3 photosites, you won't see the diffraction. If the blur from diffraction is greater than the size of 3 photosizes, say 5 photosizes big, then you will only see a blur of 5 photosites big... not 5+3=8.
Umm again not sure if you should go there so easily. Diffraction limitation depends on the size of the photosites. But does that mean a 14MP Bayer sensor and a 14MP Foveon with equal sized photosites resolve the same detail (resolution)? The short answer is no.
All that aside, I've also heard people talk about diffraction occurring at the photosite-level on Foveon sensors because of the depth the light has to travel to reach the bottom most layer. So the bottom-most layer, red, will be getting less light than the rest and the top and (mainly) the middle layer will be contaminated with diffracted red light.
If anyone's wondering which side I'm on... I like Foveon for how it tries to work and for most of its results. But Bayer CFA tends to give the most usable output <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />GTW
[/quote]
Those people have really weird ideas. The recording of diffraction is basically recording light that should have been intended for neighbouring pixels. I do not see how getting less light in the red layer would mean light intended for that pixel would end up in neighbouring pixels!
I really fail to see how diffraction softening could happen on pixel level, they are using a wrong term to describe something different.
Point remains: The foveon sensors will not be affected worse by diffraction. Diffraction is ONLY in the projected image, and the AA-filter-less sampling willnot get a more soft picture than an AA-filtered one.
Which brings us back to the reason Sigma images are "sharper"... due to the refusal to use AA-filters. If you remove the AA-filter from a Bayer CFA sensor, you will get the same kind of sharpness. Liked by some, disliked by those in the know (that is why most camera manufacturers put AA-filters in front).
Did you know, by the way, that the AA-filters are very expensive to develop and produce? They cost about the same as the sensor itself costs.