Quote Originally Posted by Steve U View Post
That seems fantastic for what you are asking of it at that range but that shot is more suited to your 100-400. The way to make your mind up is to shoot at the intended range you bought it for and then work out if you are happy. It sure looks sharp for a large crop that you showed as an example. But if you are not happywith it at 50-135 then it isn't good enough.
Oh, I know this isn't what it is suppose to be used for. I was at a park using the lens at its intended range and just shot this right before putting my 100-400mm on my camera. Overall, I know it is not a birding lens that should be used for such distant shots and would never intentionally take a shot that would need this much cropping.

I would like it to be this sharp from 50-100mm. Some of my shots are ok at all ranges but some are less so. I think maybe I will keep it but send it to Sigma to be looked at and see if it can be improved on in the shorter range or maybe I am just expecting too much out of it.