Canon EF50 f1.8 II Canon's cheapest lens but optically very good to excellent. One can never go wrong with it. My version was slightly soft with wide open but color still first class. Stop down to f2.8 and f4, it is very good (in term of sharpness). From f5.6 and below, I can rank this lens as excellent mean. Edge sharpness become excellent from f5.6. And again, I cannot notice any distortion with this lens in practical shooting. Color saturation is also very good with this lens at all apertures.
On the negative side, it is not well sealed as my EF24 f.2.8 or more expensive L lenses. For those who are in humid places, be careful and please do some prevention. Beside, since it is mostly built with plastic, it cannot stand free falling to concrete floor beyond 1 meter. What did I know? Well.... it is a long story (not a happy one). So, if you plan to use it professionally (abuse it), it is not the lens.
Conclusion: I love this lens and HIGHLY RECOMMEND it. I wish Canon can make more good lenses at this affordable price.
Canon EF50 f1.4 USM A much more mature brother of EF50 f1.8 II which have metal mount. Stop down to f2.8 and below, you have excellent edge to edge defination. His brother, EF50 f1.8 II need about f5.6 to have similar edge defination.
Conclusion: I HIGHLY RECOMMEND it. It is the one for those who need the top optic.