Yongnuo EF 50mm f/1.8 - is an autofocus normal prime lens with a multilayer coating and to be used with 35mm Canon EOS DSLR, full frame or crop sensor, camera's. When used on Canon crop camera's it will act like a 80mm lens, which is very usefull for portrait photography on such camera's.
This lens is an identical copy from the "plastic fantastic" Canon EF 50mm f/1.8 II lens. It has to be mentioned that the Yongnuo has one aperture blade more than his famous counterpart, which results in a smooth bokeh.
The picture quality is outstanding compared to the price you pay for this lens. Sharpness is great and bokeh is even more rounded than it's canon counterpart because of the one more diafragma blade.
All in all this is an excellent lens for the money.