Looking for Teleconverter for D*300mm lens.

Hi All, I am new to this site, and was wondering if anyone could help me find a Teleconverter for this lens. I have tried the sigma 1.4 & 2.0 converters, and they would not function properly on my K20D. We couldn't get the AF to work. I love this prime lens, for many reasons, & would like to be able to shoot a little further.

Thanks, Wayne

does the same advice hold for a K5 and DA*300 ?

Hi Dave AFAIK yes.

John

Just because i am a pedant;

The Pentax 1.7 converter will AF with any lens, whatever the age or original focus mode provided it can fit the mount.
The Pentax 1.7 converter has a moving element, which fine tunes the focus already set by the main lens.
In order to work the main lens must be at least somewhere near focus.
There are no AF linkages or SDM contacts on the Pentax 1.7 converter.

On a 28mm lens the " roughly in focus" latitude for error is quite large, so a 28mm M series lens and the F1.7 makes a great 48 mm AF lens.
On a DFA 100 Macro focus is much more precise, mounting a Pentax 1.7 converter will give a 170mm AF Macro, but you must still nearly focus the lens first.

Hope this helps.

Davex.