What is a good teleconverter that works with AF?

Started Nov 10, 2012 | Questions thread
awaldram
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Re: What is a good teleconverter that works with AF?
In reply to Lawnmower Shooter, Nov 13, 2012

Lawnmower Shooter wrote:

Yea if you are talking about a 2x tc, I don't even think the 50-200 will AF any more, I'm pretty sure it will add 2 stops putting you at least @F8, maybe a 1.4 would work? I am debating getting the Tamron 70-200 with a 2x tc or just getting the pentax 55-300 (the pentax is supposed to have relatively good IQ actually. Considering the Tamron option would cost me nearly $1000, I may opt for the pentax and spend the other $650 on the Sigma 17-50 I've been eyeballing.

If you are insisting on a zoom with WS then this is another story, but for pure IQ the 50-200 is a bit behind the rest.

It depends on the lens and its phase acurracy, The bigma will happily AF with a 2x on that's around F11!! whereas a 18-250 won't.

unlike cannon Pentax haven't instigated an elctronic lock so if the af module can see phase variance it will focus irrelevant of aperture.

 awaldram's gear list:awaldram's gear list
Pentax Q Pentax K-3 Pentax smc DA* 55mm F1.4 SDM Pentax smc DA* 16-50mm F2.8 ED AL (IF) SDM Pentax smc DA* 50-135mm F2.8 ED (IF) SDM +11 more
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