I think i can honestly say i have never owned such an excellent lens. On the D300, it is razor sharp, with lightening fast auto focus. As stated above its very quiet. Image quality was excellent and did not display any discernible issues with any of my filters (ND,CPL etc). Obviously on the D300 the focal length is more like 100 to 300 on the DX camera. I deliberated long and hard about if I could justify spending a LOT of money for this lens, fortunatly I purchased a little used pristine example 6 months old which made the cross a little easier to bare. The 2 negative points to this lens is its weight and cost. The quality and operation are as you would expect exemplary. If you are looking for a lightweight lens think about the F4 version. Personally I expected the weight and with it comes quality. Having just come back off a trip around Croatia lugging the D300, 17-55 2.8dx and the 70-200 2.8vr2 around, Would I buy the same lens again? Yes! in a blink of a shutter! So if your sitting on the fence as I did, see if you can get hold of one to handle before you jump, but I dont think you will be dissapointed if you purchase.