Kathy B
I bought this for my canon 80D, for more reach than I had with my 70-300L for wildlife. Inside my home I set it up on tripod and pixel peeped compared to the canon lens and found that only at 600mm did I get a bit more clarity than I did at 300mm with the canon when I zoomed in on the computer at images that were 15 ft away. Even on my heavy Benro tripod I found the weight of the lens super sensative to even a tap on the floor with my toe and very hard to manually focus because the slightest touch, in live view, caused the image to vibrate all over. In the field I found the only advantage would be if I had the setup on the tripod and the time to carefully zoom in and focus on a distant animal. But hand-holding for flying birds and such was of no advantage. Rarely would I get a clear image. The image quality was very good. Occasionally the auto focus would not work at all....I assume because it was so far out of focus it would, freeze up. But it acted like it was not even trying--just frozen. I would have to either find something else to autofocus on or manually focus to get it out of its lock up. Occasionally. Other than that the focus, most of the time, work well. Its heavy, and well built, and was not a problem for me to walk around with it hanging around my neck, and I think the weight would help with stabilizing during hand-holding. With the right tripod/head, and in good light, it would be a great lens for wildlife if you did not already have a quality 300/400mm lens--well worth the price. But only in good light, as with my 300L on the crop sensor. If I chose this lens I would consider a gimble style tripod head or whatever was stable enough to get solid shots at the 400mm+ range. I like the smooth but resistant focus and zoom rings and lock button to hold the zoom in any place that you want.