Excerpt: This is the first long lens I've owned and I have not had it out much. I have enjoyed it in action images of my grandkids and at the ranch shooting wildlife it focused so well I had deer within twenty feet from where I sat and they didn't locate me as the auto focus worked when the shutter fired it was different. Pared with my A-77 this lens worked very well. I named my 400mm "Tom the Long". Okay it is a great lens.
Pros: Consistent Output, Easily Interchangeable, Fast / accurate auto-focus, Nice Bokeh, Strong Construction
Excerpt: My first piece of high end glass and I can't be more happy with it. Super fast auto-focus, and very quiet. It's built tough and so far has stood up well to my needs. I do a lot of hiking and outdoor exploring and have no had any issues. For the price though, it would have been nice is Sony had done some weather sealing.
Pros: Consistent Output, Durable, Easily Interchangeable, Fast / accurate auto-focus, Nice Bokeh, Rugged, Strong Construction
Excerpt: Pros: Very fast and decisive focusing. Much less hunting in low light. Color is better but the hood could have been black and sturdier like the 70-200G.Cons: First Copy was decentered and soft. I have an exception G1 copy and this one was obviously broken. Second copy has slight decentering, and was slightly softer than the G1 (only noticeable in fine details such as fur at high mag.) but focus accuracy (front/back focused) at various distance was an issue.
Excerpt: On A900: As sharp as my Sigma 400mm Macro APO at 400/5.6 and Minolta 300/4+1.4xTC at 420/5.6. The Sony has equal or better resolution at 400/5.6 than my Tamron 200-500, Sigma 135-400, and Minolta 100-400 set at 400/8. For tracking moving object, the Sony lens is better than all other lens I have tested. Some color fringing could still be observed in high contrast area, but all of them can be easily removed with post processing.
Pros: Consistent Output, Fast / accurate auto-focus, Strong Construction
Summary: This lens has the reach, sharpness, and bokeh that I wanted to compliment my Zeiss 24-70 for my a99. The two lenses effectively give me a range of 24 to 400 with two of the finest lenses in the market place today, bar none. The 70-400 is quick to focus, produces wonderful color and is a quality build. I would highly recommend this lens.