I shoot NEF (RAW) 14 bit lossless compressed.
I'm pretty impressed with this lens. When I first started shooting with it I was worried because everything was soft. However, i learned that just like shooting a rifle there is a technique to it. Good support is paramount.
I'm going to start to shoot from a hide/blind in hopes I can get some of this wildlife a bit closer to really let this lens shine.
Most everything I've shot so far has been beyond 50 yards... which if you think about it is pretty amazing for this lens. Most of the photo's are 50% or 100% crop. (Except for the Kestrel the other day that was about 25%)
I rented a 1.7 and a 2.0 teleconverter to see how the camera and lens handle them. Then I'll see which one I want to purchase.
I only have a week rental so i hope the weather cooperates!