Hello hello!
Lets watch my review of Canon EF 50mm F: 1.8 STM lens. The focal length in APS-C camera ideal for portraits, the brilliant bokeh, completes all this great sharpness. Optical defects - chromatic aberration and vignetting are more visible in the tests, at the maximum aperture opening than on actual photographs. Stop just to F 2.8 is enough for defects to have been completely disappeared.
A similar focal length for Helios (58 mm) and Takumar (55 mm) lenses lets you compare the quality and "character and soul" of vintage lenses with a modern design.
In my opinion it is a very nice lens, and considering its low price it is actually such a "must have" in cameras with APS-C matrix.