My first impressions of the lens were that it wasn't as heavy as I thought it would be and it felt extremely well made. I was very pleased that it came with a tripod collar - not always the case. The lens is well balanced and comfortable to use but has a tendency to feel slightly front heavy on my D810 and D800 but once the MD12 grip is fitted it is much better balanced.
Modern digital cameras have such good high ISO capability that the maximum 5.6 aperture is not an issue for me. The VR is so good I have been to hand hold the lens at shutter speeds well below 1/500 at 500mm. Sharpness looks to be very consistent throughout the range of apertures and zoom lengths. In fact, this lens is much sharper than I had expected for the price. The autofocus is fast, sharp and accurate, slowing only slightly when light levels fall significantly. The close focus is acceptable - after all this isn't a macro lens. I have not experienced any focus breathing and even hand held the lens stays put at the zoom and focus I set. So what's it good for? My main reason is for photographing Birds of Prey and wildfowl plus a bit of sport but the possibilities are far wider than those. I'm now itching to use it for motor sport.
I purchased the lens to replace my Sigma 150-500mm as I was not always happy with its focus performance - did I do the right thing - you bet, this lens outshines the Sigma in every way. Also it is a natural progression to my usual set of "go-to" zooms, 14-24mm, 24-70mm, 70-200mm and now 200-500mm. Would I recommend this lens? Emphatically yes!
Modern digital cameras have such good high ISO capability that the maximum 5.6 aperture is not an issue for me. The VR is so good I have been to hand hold the lens at shutter speeds well below 1/500 at 500mm. Sharpness looks to be very consistent throughout the range of apertures and zoom lengths. In fact, this lens is much sharper than I had expected for the price. The autofocus is fast, sharp and accurate, slowing only slightly when light levels fall significantly. The close focus is acceptable - after all this isn't a macro lens. I have not experienced any focus breathing and even hand held the lens stays put at the zoom and focus I set. So what's it good for? My main reason is for photographing Birds of Prey and wildfowl plus a bit of sport but the possibilities are far wider than those. I'm now itching to use it for motor sport.
I purchased the lens to replace my Sigma 150-500mm as I was not always happy with its focus performance - did I do the right thing - you bet, this lens outshines the Sigma in every way. Also it is a natural progression to my usual set of "go-to" zooms, 14-24mm, 24-70mm, 70-200mm and now 200-500mm. Would I recommend this lens? Emphatically yes!

