weekh
Oh, I cannot tell between the two.
But I have seen my own photo prints of pics taken with my CZ 50 f1.4 and Canon 50 f1.4 EF. But I like both anyway.
The Canon 50 f1.4 seems to give a slightly harder edge to the picture.
The CZ 5- f1.4 almost always gives you a picture of a person that looks soothing and nice to view. The subject can young or old, pretty or normal looking.
I think optical engineers decide resolution, contrast, bokeh, colour characteristics, gradations of tone, flare resistance, reduction of abberations, reduction of distortion etc...when they design the lens. Then the mechanical / electronic engineers design the the barrel material, the gearing, iris blades closing time (Leica very particular about this for R lens) and (if AF lens) USM motors, iris magnets, contact points, etc...
And all this within the design cost limit that the company set for them.
There seems some trade off between resolution and contrast. Perhaps using expensive and special glass can help.