For quite some time, I have been looking for a solution to the problem of a strip, which appears at the bottom of the picture. The strip is visible when the histogram is streched.
I use the following setup: Canon 6d, Samyang 135mm (both new). However, I encountered the exact same problem with another similar setup, namely a used Samyang 135 and a Canon 6d.
I tried to use various types of flats (proper exposition, overexposition, long exposure time). Nothing seems to help.
I stacked the photos in Siril, DSS, APP and PIX and the result is still the same. I can't find a solution anywhere.
Do you think the problem is with the camera or the lens?
I'd appreciate any advice or suggestions you could give me.