10 out of 10 points and recommendedSharp Crisp Pictures Fast Focus Beautiful Bokeh Very Little Image degrading with 1.4 Converter Very Good Image Stabilization Global Dock offers customization and firmware updates at your computer.Heavy but similar to other f4 500mm lenses. 1/2 pound heavier than new Nikon 500mm.
I am a Amateur Bird Photographer. I've owned this lens now for 5 months and I am using it primarily for wildlife and bird photography. I took a leap of faith purchasing this lens after reading a very thorough review from a Canadian Wildlife Photographer. I find the lens to be very sharp creating those 3-d quality prime images. My birds in flight are mostly spot on. Still working on my technique to get a better capture rate. I used the Global dock to adjust focus very slightly as I felt it was forward focusing. This can be adjusted very easily with the dock. I find my images excellent wide open but seem to improve at 4.5 and higher. I was also able to customize the focus speed to faster focus. I have been using the lens on a Nikon D750 with tripod and gimbal head. I've hand held the lens but I can't hold it up for very long (I'm 70 years old) I've taken it on short hikes with a monopod which works very well. The build quality is excellent and I can't imagine the Nikon or Canon equivalents to be worth the additional $5,000+ price tag. Being retired and having put the kids through college, I could have afforded the Nikon at $10,500 however I decided on the Sigma and don't regret it. I bought mine from Adorama - Excellent service.reviewed September 15th, 2017