I decided to buy the Yongnuo 50mm F1.8 after struggling with the classic Canon EF 50mm F1.8 (Made in Feb 1987). I’ve been having focus issues as well as exposure issues when I use the Canon EF 50 f1.8 when attached to just my Canon 5D Mark II. I’ll be using the Yongnuo lens for the next few weeks.
Here’s a test shot of The Camera Store TV Host Chris Niccholls. This was shot on the 5D Mark II at 1/160, f1.8, and ISO 400. F1.8 on the Yongnuo is sharper than the Canon. However, I really had to use AF Microadjust to get the lens to focus properly. I had to go -15 on the microadjust!!