TC 17 for Nikon 120-300/2.8?

[ricardo00]

Nice shots. Did you notice a difference in AF speed between the two TCs?

Thanks! For sure, the 1.7TC is slower than with the 1.4TC and the lens alone is fastest.

 

[Dionigi Colombo]

The 120-300 I use mostly smooth, I have all 3 Tc's, with Tc14iii the loss of quality is almost invisible with Tc17ii you notice a little loss of both quality and speed af(it also depends a lot with what machine you use) the Tc20iii I find it too poor both loss of quality and speed Af

Unfortunately, on the tablet I have few photos with 120-300 and Tc’s

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[Woodpecker]

With respect to using the 500/4G with teleconverters, Nikon’s compatibility chart indicates that AF would work with ‘cameras that support f8’, for which they footnote a list including a few DSLRs including the D5, D4, DF, D850, etc. and a few earlier Z bodies. The 120-300 isn’t on the list. Of note, it shows the 500PF will only have AF with the TC14E III. (It seems the list hasn’t been updated in some time; I’ll continue to look for an updated one.)

As this list deals with F-mount lenses I am pretty sure it got a little out of focus in terms of maintenance . And as far I can remember, I would expect that your 120-300 is too new to be on the list. When I look at the list, for the 500PF both TC-14 models are listed as "AF limitations". The obvious reason for that is that at a start aperture of f8 the cameras listed in the footnote still have some AF, but even for the D850 there are only ( I think it was) 12 AF sensors in the center that remained active, which is the reason for the statement "AF limitations". Unless you only shoot in bright light and always leave four focus point dead centered in the frame, IMHO I would simply forget pairing a f5.6 lens with a TC on a DSLR. I tried it with the 500PF on a D850 and it's simply not worth it.

With the Z8 I couldn't test it, because at the time my F lenses were all gone. But @ricardo00 shows that it works with a Z, because they don't have the f8 limitation the DSLR's have.

I 'm pretty sure that it doesn't mean anything that your 120-300 is not on the list. Technically you should be able to use all AF-S TC's because at the worst a TC-20E III would give you a 240-600mmm f5.6 and with that all AF sensors on one of the listed DSLR's will still be working.
What compromise you would have to make in terms of IQ and usability of the zoom range is another story (cf. post above). From what I have heard from people having used the 120-300 it should have enough resolution headroom to make it worthwhile trying a TC longer than 1,4.

Although time is pretty limited at the moment I certainly will make some tests before bringing the 500 to the Nikon workshop, because the lens is workling perfectly, it just makes some noise. This will certainly be a pragmatic, "un-academic" test, but it should give some indication. The test TC-17 is on its way from Austria to Germany ...