At what aperture settings is the 50L sharpest?
I ran a test through FoCal software, aperture sharpness test, and it shows the following:
50 L: Way sharper at 1,8 than 1,2 (obviously) but it is also quite a bit sharper at 1,8 than at 2,2. The very sharpest aperture is f5.
(Have no idea if this goes for every copy on every body, but this is a 2012 50 L on a 1d X)
It has the "dreaded shiftfocus", but I never worry about it, even up close, properly calibrated I don't notice shift. What a lens this is though, if you shoot test charts you might feel you overpaid, use it like a workhorse in all weather and shoot wide open and 1,8 and the 50 L will make you VERY happy....