Did you try to get the actual aperture size the SAME for each comparison, ie actually do the math to see what setting would be the same on the 35mm focal length as well as the 200mm focal length? not doing so can be one source of optical error.
Do you mean the t-stop? How would I calculate or even set that. I have to rely on the camera settings to set the f-numbers. I think people are still not understanding that these images are real. I did shoot these images with real cameras and didn't manipulate anything on them. Then I uploaded them and created a database file that links to the images when the settings are chosen in the dropdown list.
T stop is the amount of light the lens itself lets through the bottom of the lens and into the camera, that will differ between lens mounts. FD is slightly bigger then EF mount, etc.
I mean the actual diameter of the aperture. Aperture is what the f stop/f number refers to. diameter of that opening in ratio to the focal length of the lens.
I understand that its common for people to simply say that the f/ stop is identical between lenses and brands, as if it was a specific sized bolt or machine screw. But when you actually set down and do the mathematical calculations to get an aproximate diameter for the opening at each setting for each lens, you can start to see real world differences.