[legacyb4]

I'm a bit confused trying to figure out exactly what teleconverters work with what lenses with K10D/K20D.

Is there a definite list with what works with:

a) older screw-drive K mount lenses (like the Tokina ATX 70-200)

b) newer SDM lenses (like the DA* 50-135)

Thanks.

[palmor]

This list was put together by a fellow forum member so I take no credit.. just providing a link


https://www.pentaxforums.com/forums/714305-post520.html

[Ash]

That's a good summary, and would probably be quite accurate.

Both Tamron and Kenko's modern servings do have SDM capabilities by virtue of their electrical contacts, but reliability depends on lighting conditions.

Pentax F TCs, whilst of excellent optical quality don't have SDM capabilities (they lack the SDM contacts) and so would not be the best choice for the 50-135. The beauty of the Pentax TC series is that they can actually make MF lenses into AF ones (to a point) by their internal mechanisms (not by moving the actual lens's focus ring).

There are no newer Pentax TCs available yet (really should be on the roadmap) to support SDM, which would provide at least the opportunity to have more reliable AF with Pentax's SDM range of lenses...

[legacyb4]

Thanks, that's good to know!

Looking at the list though, seems like it's still pretty hit and miss. Why is it taking Pentax so long to release one? I'm betting that pretty much every DA*50-135 owner would pick one up if the price isn't overly high!

[dadipentak]

As the Dave referenced at several points in Daniel's excellent compilation, I'd say the Tamron-F Pz-AF MC4 1.4x is very useful and performs well optically--but they're scarce. I don't understand why Tamron's not cranking them out (or why Pentax doesn't offer one.)