Hi Ikka
Re your questions about the TC16A..... I have used one on a 500mm F4P lens
and the results were reasonably OK. I did however get quite a bit of
vignetting in some situations when used at F4. I also used a modified
TC20E on this lens and the results were superb! Better than with a my
TC301. I would say that you should be able to focus a slight bit closer
with the TC16A but I personally think that it would not really be noticable!
The distance that the lements move in the TC16A is not very far and I don't
think that would do much as an extension tube!
Hope this helps and happy bird photography!
A
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Albert Froneman [EMAIL PROTECTED]
South Africa
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