Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers. It only takes a minute to sign up.
Sign up to join this community
I took some photos with my a7 iii and a Tamron 28-75 lens yesterday and one of the subjects was wearing a shirt made with pink and white fibers. I'm seeing some weird artifacts in the colors that I've not seen before. I do have a UV filter on the lens which is the only thing I can think of. Any ideas what this is?
Also any ideas on how I might be able to fix this in Photoshop? I have no idea where to start.
It's color moire... notice that it's just blue and reds but not greens, which means it is occuring at 1/2 pixel frequency/spacing.
To eliminate it you need to change the pattern of the fabric so that it is significantly different than the pattern of the red/blue pixels on the sensor... this can be done in several ways.
Blurring is a primary method... stopping down into diffraction, an intensional slight defocus, or a soft focus filter. I'm not aware of any add-on AA filter options.
Another is to change the size of the pattern by changing it's magnification... change the FL/Zoom/distance.
I've often read that fixing moire in post is easy; but IME it is seldom terribly effective... particularly with color moire.
It't an interference pattern, also called moire pattern.
The cause is, that the pattern on the shirt has almost the same size as the pixels on your sensor. The small deviations lead to an interference pattern that looks like what you see.
You can get rid of those patterns with a low pass filter in front of your sensor. Getting rid of those patterns in post processing is very hard.
