HI. Maybe you guys can help me with a little thing.

I'm testing settings on two 5D3s next to each other on a glidetrack shooting the same stuff at exactly the same settings and one is (ever so slightly) more contrasty and warmer than the other.

One is shooting with the 50mm 1.4 and the other with the 85mm 1.8

I'm guessing this is the reason but I figured that more experienced people than I might have a good explanation. The difference is absolutely minute so it's not a problem, I would just like to enhance my education on this matter of lenses.

Thanks in advance

The coatings might be slightly different between those lenses. The 85 was introduced in 1992 and the 50 in 1993, so it's unlikely that there was a big change in the formula in that exact year. Then again, maybe your lenses have very different date codes. In that case the formula might have changed or there might be aging involved.

What was the aperture in those shots? If near wide open, the lenses will show variation due to the different glass. If stopped way down, the aperture opening can vary slightly even on the same lens from shot to shot as the aperture closes slightly differently each time. If around f/5.6 or f/8, you'll see the least variation due to glass (open) and aperture (closed). In this case, it would come mostly down to the coatings.

Thanks Jon Good thinking.

Both at 4.5