*production* A77 ISO samples

Started Aug 28, 2011 | Discussions thread
Midnighter
Senior MemberPosts: 1,727
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My answer is...
In reply to Docno, Aug 29, 2011

Find some images of fine cloth on the net (or take your own photos) and down-sample them, you will soon see what I am talking about. Bayer images appear to become sharper when you down-sample them. What you are seeing is the effects of the AA filter being compensated for, the image sharpens. However in doing so you lose detail. All you need do is downsample the image too far, or to a particular dimension that does not suit the resolution qualities of the image or software. Down-sampling reduces apparent image softness, by a huge amount in Bayer sensor images but very little in Foveon sensor images (or with Bayer sensors that have had the AA filter removed). However it always messes with image detail, it can be seen in reality and it can be logically deduced.

The reason that I up-sample to 2X the size of the large image is that the software is forced to 'guess at' data for BOTH images, not just the smaller one. This does away with the 'penalty' on the smaller image of the software simply enlarging it to the same size as the higher rez image and guessing poorly... the software gets a chance to guess poorly on both images.

Docno wrote:

Can't understand how upsampling is preferable to downsampling. Downsampling removes data that exists, and I can see how that might 'mess with patterns' in certain situations, but not how it can remove perceived detail. Upsampling is creating ('guessing at') data that does not currently exist by interpolation. I can't see how that process can lead to a better image. Do you have a source for your claim? I may be wrong... just curious.

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