msmoto.

I too have had very good results with the 70-200mm f2.8 and the TC17. I am looking forward to using this with a TC2.0 III someday which should be even better. This is such a good lens! When I bought it, it nearly crippled me financially but it was worth every penny really and is my favourite portrait lens. To my surprise, it is also very good for product shots in studio and location as well and I often use it in preference to anything else.

@ DJBee49

Good point about the TC-20EIII with the 300mm f/4 being good. If one searches on the forum you will find a comparison I did with the 70-200mm f/2.8VRII with the TC-20EIII and when stopped down a stop it is excellent even when compared with the 400mm f/2.8VRII. Actually, the first generation of the 80-400mm f/4.5-5.6 VR (Ser No 201XXX) is an excellent performer when I use it and compares favorably with the 400mm f/2.8 and the combination of 70-200 plus TC above. The primary issue with the 80-400mm is the focus speed.

@ msmoto Nikon will sometimes say a combination will not work when it actually does function under some good conditions. They like to error on the conservative side so no one can get into a hassle about promising something which is not true.

I am sure that this is true and makes the dissemination by users of the real day to day possibilities, without 'corporate responsibility' getting in the way, very important.

On a related note, the reason this is all important to me, and I suspect others, is that I can neither afford nor justify the purchase of a 300mm f2.8, or more pertinently, a 600mm f4- however much I would like one....or both! Therefore, the performance of the 300mm f4 and TCs of various strengths is of great interest. This is in fact why I got the D800, not for the 36 megapixels or the video (I don't shoot video and my D700 had ample sensor resolution for me) but for the ability of the sensor to accept good AF performance at maximum apertures of f8. Thus, when I can afford one, I will get the TC 2.0 III and have a usable 600mm lens set up. The D800 and TC2.0 III is a CHEAPER option-by about half- than purchasing a 300mm f2.8 and TC2.0 III. I know it still is not going to be quite as good as the f2.8 option but I am not in a position to choose this anyway. Perhaps I would if I was able to justify it from professional earnings but wildlife photography is a hobby, not my professional photographic sphere. Maybe one day!

@ DJBee49...excellent point about the physical limits and potential for rear element/TC element colliding. Once this happens I suspect it could destroy both lens and TC. Playing with the lenses and focus points is probably the best solution to figuring all this out.

Nikon will sometimes say a combination will not work when it actually does function under some good conditions. They like to error on the conservative side so no one can get into a hassle about promising something which is not true.

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Thanks for the replies.

In fact the 300mm f4 WILL autofocus with the TC17 and I believe the TC2 as well. I have successfully used this combination on my D700 many times. It sometimes hunts a little and can be slow but it does work- in moderately bright light at least. The D700 allows full autofocus at f5.6 but struggles a little at f7 or so, whereas the D800 is designed to allow autofocus at f8 so it should work perfectly well, which it does. As msmot suggests above, it works fine in single point servo and with 9 and 21 point AF settings. The problem is that I cannot SET either AF auto or AF 3D with this 300mm f4 and the TC 17. The camera just will not come up with the setting. I do not have any other TCs to try out as substitutes for the TC17. I suspect some sort of electrical conductivity problem with this particular lens or TC and wondered if anyone else had had the same problem and if so what the solution was.

This link says it all.

http://www.nikonusa.com/en_INC/IMG/Assets/Common-Assets/Images/Teleconverter-Compatibility/en_US_Comp_chart.html

The 1.7 Teleconverter will not let you AF with the 300 f/4.

I am just guessing, but it could be that the AF modes available at f/7 may be limited. If you have a TC-14EII, try it and see if it works.

The 300mm w/ TC-17EII works in single servo AF and in continuos servo with a single point, correct?

My 300mm f4 works fine on my D800. No problems. When I put my TC17 on it, I cannot select either 3d or Auto AF modes. When I put the TC17 on my 70-200mm f2.8 I can select all the AF modes. Curious. For some reason there is a specific problem with the 300mm and TC17. I have tried cleaning all the contacts to no avail. It may have been like this all along because I rarely use either 3D or Auto settings on this lens, indeed I may never have tried these settings on this lens before! All the other AF settings seem to work OK.

Any ideas anyone?