Sigma 150-500mm f/5-6.3. An unbelievable bang for your buck if you ask me. I still have a few more tests to put it through, but I don't think it will have a problem at all. I haven't even put this lens to use on the tripod yet. These shots were all handheld. The only thing I think I wished different, would be the AF being a touch faster. Don't get me wrong though it's still as fast as my other lenses, I just can't think of anything else to nitpick
The photo of the killdeer, and the one of the Gads were shot at 500mm.