DP2M macro moire?
I'm a new Sigma owner and am enjoying my DP2M very much. However I sometimes see an image artifact that is annoying: an alternation of red, green and yellow(?) that doesn't exist in the original subject. Below is an image processed heavily in SPP, and below that is a crop that exhibits the phenomenon (look at the vertical 'columns' in the crop). Anyone know what's going on or what I'm doing wrong? Thanks for looking.
You are shooting at -1.6 bias which puts you at 326 ISO. You are also getting some underexposure due to the bright sky. When you push the image with SPP the color banding is shown in the darker parts of the image. If you must use a negative bias be sure to use 100 ISO.
Color noise is something you get with the Foveon sensor if you push the shadows really hard (which I think it is in that case).
If you like raising shadows think about shooting ISO 200, but at +1.0 ev. Then when processing in SPP move exposure down to fix any highlight clipping, use fill light no more than +0.3 to recover things a bit, and output a 16-bit TIFF file to finish in some other application using a combination of brightness and levels shadows/highlight recovery to restore the overall scene brightness and bring up the shadows more.
You may be able to manage just in SPP if the highlights are not too blown, as fill light also acts to recover blown highlights to some extent.