Nikkor TC20E Converter
Well, when I finally found a Nikkor TC20E (designed for the AF I/S Nikkors [only]) at a good enough price to take a screw driver to it to remove the front bayonet so that I could file off a small tab that prevents the mounting of anything but those big and horribly-expensive EDIF-AF-I/S Nikkors with the built-in focus motors, I can report a few findings. (Whew! I trust you didn't get as lost reading that as I did writing it!;-) With the small tab removed, the relatively compact (compared with the TC300/1), but surprisingly heavy (3/4 pound) TC20E will fit a few lenses the TC300/1 won't, plus the usual ones 300mm and over that it will (though it will not AF with any but AF-I/S lenses...). On the AIS 135mm f2.8, performance was not very good (the TC200/1 would be better). On the 80-200mm f2.8 AF, it was fairly good at the short end of the zoom range by f4, and quite good by f5.6. At the long end, it was OK at f4, and fairly good by f5.6. This converter works better on the 80-200mm f2.8 than the TC200/1 does, though it is not ideal (and not as good as the performance of the TC14/B/C on this lens). It is also very hard to focus the 80-200 with the TC20E installed. The TC20E was disappointing on the 300mm f4 AF - the 100-500mm Cosina zoom on its own easily beat this combination (though it
is only 500mm instead of 600mm...). With it on the older 500mm f8 mirror, conditions may not have been good enough to see the limits of this combination, but results were not high-quality. I did not have time to try the converter in a macro set-up, where I often use converters for increasing magnification. Preliminary conclusion: this converter probably ought to be left for use on the lenses it was designed for, though it does provide decent performance (better than other 2X converters) on the
80-200mm f2.8 AF Nikkor, and it MAY be good for use with long extension tubes on the front when doing high-magnification macro work.
"Hope This Helps"
David Ruether (firstname.lastname@example.org)