theSuede wrote:
About the latest examples shown by everyone (thank you for your work btw!) I have to add a little something for the LR/ACR-users: Until Adobe fixes the profile for the 7D, it will seem a little bit more noisy than it \"should\" when used with those converters.
One of the green channels is more sensitive than the other (it has a higher spectral transmissivity - it lets more wavelengths through). It\'s also expanded towards the red channel by quite a lot.
So to get maximum colour accuracy, you need to demosaic the 7D as \"four different colours\", it\'s not R+G+G+B.... It\'s more like Red+Yellowgreen+Green+Blue. I\'m not sure that LR/ACR can do this unless specifically told that the camera needs another demosaic scheme (like the Fuji\'s and some others)
I\'ve added an example of how this effects colours that are somewhere between yellowish green and warm red. This is the EXACT same raw, with EXACTLY the same settings of sharpening, converted in EXACTLY the same raw engine (my own MatLab development). The only thing that differs is that one is de-mosaiced with an algorithm that supposes that all four colours are totally different from eachother, normal demosaicing usually supposes that the two greens in each RGGB-group are the same colour.
that is quite interesting
and perhaps this time the final ACR actually will make a difference for the maze stuff and the problem will go away
are you sure the CFA use 4 filter types though and your 4 color thing is simply not just dealing with the unbalanced, but identical greens?
otoh, i also notice it with colors far from warm red and yellowish green, i can see it on white backgrounds, blue, etc. (granted many blues have lots of green in them and of course white has lots too)
Oct 11, 2009 at 09:33 PM
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