I had a chance to take a few pictures of a pigeon on the roof of a building right across my apartment using my d600 + 500/4 vr and the tc-17e, specifically I wanted to see the results with tc-17e, since I had very unpredictable results with this combo attached to d7000 before. It was a sunny morning and the pigeon was exactly at 30m away (checked it on the focus scale). The camera was set to standard mode with +3 sharpening, high iso noise reduction at normal, and the pictures were taken in fx jpg format full resolution and hand-held (vr on). The first example data is: 1/1500, f/9.5 (1 stop down for max sharpness), iso400, -0.5ev (a habit from d7000, apperantly not good for d600). The second example is with: 1/2000, f/9.5, iso800, -0.5ev. The 100% crops of both pictures are shown below each one. The pictures are brightened up slightly, but no other processing is done. These two examples are representative to the others being very similar. Some of the dots on the blue background are the dust on the window. Also, pictures are saved with jpg compression with only good quality in order to keep the files below 100kb. I found the d600 to be much better performer than the d7000 when it is used with tc's. I think the major advantage is the high iso performance that enables a photographer to shoot at much smaller apertures (large f numbers) with high shutter speeds. Also, f/8 sensitivity is important to get accurate focus where it was not possible before. Also, in camera noise suppresser seems to keep detail much better than the d7000. These are my findings so far, I hope they are useful, any comments would be welcomed.