Which Canon 50 mm f/1.8?
The inexpensive (Canons least expensive lens) EF 50 mm f/1.8 II has embarrassing low build quality for a lens from a major camera maker.
Image sharpness is only decent when the lens is wide open at f/1.8. The 2 photos in post #4 seem to show that, less than sharp when used wide open.
The wide open drop in sharpness is common to most inexpensive 'fast' lenses, regardless what company made them.
But stopped down to f/2.8 or smaller the sharpness is quite good. So when you want as sharp a subject as the lens can deliver don't set the lens aperture to wider than f/1.8.
Unfortunately the low build quality means the lens only has 5, straight, and sharp edged aperture blades so the lens delivers some of the worst looking bokeh of any camera maker lens.
The low build quality of the EF 50 mm f/1.8 II is also why so many of them break into 2 large non-repairable pieces when the lens is dropped.
But, being as inexpensive as the lens is, it doesn't hurt to much if you need to replace one you dropped.