Help re. 2x Converter

I have just bought a (ahem) Jessops 2x converter MC Pz/AF. The main reason was to see what results I could get with my DA 50-135*. I assumed that the Pz meant that the electrical contacts were there to do the focussing - and indeed they are. However, when connected it will not engage AF. It does work on screw-drive lenses.

Does anyone know if this is simply a compatability issue, or should I be able to use SDM? The results in manual mode are not bad, so I may be tempted to just live with it, rather than returning the item.

Cheers

Tony

If the Jessop TCs are like the Kenko TCs they are all Pz/AF but only certain ones AF with SDM. In Kenkos case Pz/AF-SHQ. So I think yours may not work with SDM only lenses.

It does sound like a compatability issue, the body obviously knows an SDM lens is attached otherwise it would revert to screw drive, is there no one in your are with another SDM lens you could try?

Does it have 6 or 7 contacts !??

If only 6 then no lens info will be relayed to the camera, so it won't know what the focal length is set at, therefore can't move !!

My Sigma lens will not work properly with my x2, other lenses are fine !?

Thanks all for your responses. Looks like it won't work with the 50-135* then (don't know any Pentax users other than you lot!!) It does have the seven contacts and looking at the exif the camera has lens and focal length, but clearly the un-magnified length. Which therefore poses the new question - should I turn off image stabilisation or not