Just got the sigma 50 from a fellow FMer and has been shooting with it all day. I wondering if my copy is sharp enough and how do I check for focus accuracy.
Just go out and shoot a bunch. If the images ate sharp...you are done. If not, then you need to dig deeper to ensure it wasn't human error causing the focus issue.
i had 2 different Sigma 50mm one on my d5mrk2 and it was like god and the one i had on my d610 was sent back to the factory 2 times for focus problems,