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Question

Camera Raw over-sharpens green channel?

Forum|Forum|7 years ago
February 4, 2019
1 reply
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I'm processing some astronomical images. These are Canon CR2 raw files.

When I open them in Camera Raw I find that the bright stars have a dark offset halo around them in the green channel. Red and blue channels look normal.

The halos have pixel values of zero (general sky background around them is ~3000) and then jump to values of ~20000 on the star itself. It looks as if a severe sharpening process has been carried out but only on the green channel.

If I open the image with a different raw converter it all looks normal. Here is a 200% screen grab.

Is anyone aware of a problem with Camera Raw??

Thanks,

Graham.

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Inspiring

what camera are you shooting with and what does the other RAW converter image look like?

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I'm using a Canon EOS 5D Mk3. This is a 90 second exposures at ISO1600.

The image below shows the R,G and B image planes from DCRAW (top line), and the similar ones from ACR (bottom line).

There is some nebulosity in the image - so the noisy background is real. My big concern is how the dark rings can have occurred in the green channel.

Thanks for any help or suggestions you can make!

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Sorry, I should have added that I'm working with the latest versions of Photoshop CC and ACR!