September 01, 2014, 11:01:21 AM

Author Topic: Will Canon ditch the AA Filter?  (Read 19938 times)

LetTheRightLensIn

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Re: Will Canon ditch the AA Filter?
« Reply #180 on: January 23, 2014, 05:54:51 PM »
The quality with which LR renders my 7D images only seems to get better and better with time and each subsequent version, so as Adobe optimizes their demosaicing implementation, any inherent error is clearly diminishing.

Thanks again for all your great posts on this! The problem with Adobe is that they seem to be very secretive about any improvements concerning ACR or LR, their official changlog only reflects a small part of the changes ... or is there any Adobe or 3rd party documentation on their raw converter improvements over time?

Not that I know of. Sometimes changes to sort of appear out of nowhere. Although I think they did announce the changes when they got rid of 7D mazing.

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Re: Will Canon ditch the AA Filter?
« Reply #180 on: January 23, 2014, 05:54:51 PM »

dude

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Re: Will Canon ditch the AA Filter?
« Reply #181 on: January 23, 2014, 07:30:14 PM »
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CarlTN

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Re: Will Canon ditch the AA Filter?
« Reply #182 on: January 24, 2014, 01:24:52 AM »
The foveon has no sensor pattern, the color pixels are stacked.  If by pattern you just mean a "grid", then the solution to that would be to randomize the sizes of the pixels, and perhaps also make them hexagonal shaped.  I had thought years ago that Fuji made a sensor with hexagonal pixels rather than square, but I think I was wrong. 

In film, color is present at all locations, in a very thin membrane.  The grain "resolution" is randomized a bit...it's an "analogue". 

Digital sensors should aspire to do the same thing, in my opinion.
Fuji Super CCD: http://en.wikipedia.org/wiki/Super_CCD
A recent Fuji sensor patent: http://www.fujirumors.com/fuji-patent-x-trans-evolution-sensor-with-enlarged-green-pixels/

Interesting, thank you!

dilbert

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Re: Will Canon ditch the AA Filter?
« Reply #183 on: January 24, 2014, 03:29:02 AM »
AA filters definately decrease resolution but equally not having them greatly increases moire and aliasing these are known facts and both of these artefacts lower the visual perception of sharpness & contrast.

Not having an AA filter does not by default mean that you have moire or that moire is increased. The presence of moire is highly dependent on the subject of your photograph. The lack of an AA filter only means that in certain circumstances, it is possible to observe moire where with the AA filter it would not be observed.

Separately, I'm not convinced that aliasing is worth doing anything about at the sensor level.

jrista

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Re: Will Canon ditch the AA Filter?
« Reply #184 on: January 24, 2014, 04:53:10 AM »
Hmm. I can't imagine that such a thing is a huge problem. It's not all that different from Sony's "Emerald Green" CFA that they introduced many years ago (they called it RGBE). Their "Emerald" had more blue in it than the standard green. Based on all the sample images at the time, it actually produced better color accuracy...but it would be the exact same thing as your describing with the 7D.

When you have two similarish but different greens a typical de-bayer will get tricked and create maze patterns.

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I also can't imagine that it would cause a loss in resolution. I mean, the crux of any bayer demosaicing algorithm is interpolating the intersections between every (overlapping) set of 2x2 pixels. Because there is reuse of sensor pixels for multiple output pixels, there is an inherent blur radius. But it is extremely small, and it wouldn't grow or shrink if one of the pixel colors changed. You would still be interpolating the same basic amount of information within the same radius. I remember there being a small improvement in resolution with my 7D between LR 3 and 4, and things seem a bit crisper again moving from LR 4 to 5. I suspect any supposed loss in resolution with the 7D was due to the novelty of Adobe's implementation of support for the 7D, not anything related to having two slightly different colors for the green pixels. The quality with which LR renders my 7D images only seems to get better and better with time and each subsequent version, so as Adobe optimizes their demosaicing implementation, any inherent error is clearly diminishing. BTW, there is no way anything Adobe has ever done that could possibly "knock off 1-2mp worth of resolution" from the 7D.

Well if you compared the first ACR that handled the 7D, which also mazed a lot, the version that came out right after where they fixed the 7D mazing, there was a subtle lowering of micro-contrast. My 1-2MP was just a wild guesstimate. (1MP off of 18MP really is not much when you think about it, especially what it would mean for linear resolution change, although maybe calling it 1-2MP was overdoing it)

Ah, I see what you are saying. Well yes, you do need to properly integrate the specific bayer pattern. If there are two shades of green, that does need to be taken into account. It won't reduce resolution, though. As I said, spatially, it is the exact same source resolution, use of an alternative green is not going to reduce microcontrast or anything like that.

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DPP will produce a fairly jagged result, ACR/LR produce a very clean result. Based on the sample below, ACR is actually sharper and supports even finer detail resolution:

It depends, I find ACR can get pretty jaggy in some cases, at least with non 7D cameras. I do find I can pull a bit more finer detail with it than DPP though.

I'd like to see some examples of ACR being jaggy with a camera that has an AA filter. If your camera lacks an AA filter, then certainly...but a sensor with a proper OLPF produces remarkably sharp results with LR's demosaicing algorithm. Sharper than DPP and most of the demosaicing options in RawThearapy. Some demosaicing options in RawThearapy operate more on a "super-pixel" type demosaicing algorithm, so you lose output resolution, but you gain color fidelity and lower noise...kind of hard to compare LR with those options.
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Re: Will Canon ditch the AA Filter?
« Reply #184 on: January 24, 2014, 04:53:10 AM »