Having recently upgraded the entire camera kit I bought this to go with a 70-200mm F2.8 GII ED lens. As with the D4/D800 autofocus works well at f8, so it's the perfect companion for this lens on the DX format D7100, giving an equivalent of 200 x 2 x 1.5 = 600 zoom, or in camera cropping will increase this to 780mm.
I'm no professional, nor even a knowledgeable amateur, still practising and developing my skills, but for someone wanting to go to the next level, or a pro who will get the best out of the increase in focal length it's hard to beat (and the only option for 2x with this quality of optics).
I'm no professional, nor even a knowledgeable amateur, still practising and developing my skills, but for someone wanting to go to the next level, or a pro who will get the best out of the increase in focal length it's hard to beat (and the only option for 2x with this quality of optics).