HD PENTAX DA AF 1.4X AW Rear Converter

I have the same converter and I'm pretty certain that I tried it the other day with an SDM lens (55mm) and an SDM/PAF lens (60-250) and it focused both (although the SDM only lens did hunt a lot and could always lock focus) :

Hi Lennybloke

This is a bit confusing, it certainly AF's with all my screwdrive lenses and with all HSM Siggy's, but not with the DA*300 and not with the DA*50-135 either. The contacts on the TC look to be identical to those on the latest Pentax 1.4 HD TC, so I would expect it to work. Could it be that Pentax have done something in the latest firmware updates to disable non Pentax AF TC's? Does anyone have any other ideas why this TC will not activate the SDM?

Regards
David

Hi David

Let me double-check what I just added to the post this evening, but I thought that if the lens is SDM and PAF (such as the DA*300) then it would use the screw drive AF (and work fully) - if it is an SDM only lens (such as the DA*55) then it won't work properly (there are a couple of independent TC's that do work - Teleplus PZAF SHQ 1.5 and Tamron PZAF 1.4 - I believe).

Cheers
John

Thanks John, I can confirm I've just tried it on all three of my cameras (K-3, K-5IIs and K-01) and it's the same on all of them. All three cameras revert to 'MF' as soon as the TC is attached. The K-01 has not got the latest firmware update that was added especially for the new Pentax TC, but the other two cameras do have latest firmware.

Regards
David

I have never known a teleconverter that works with HSM to at least attempt af with SDM.

Hi Mike, not sure what you mean above, could you clarify?

The Pentax 1.4 TC works with both HSM and SDM, the Kenko 2x PZ-AF works with HSM, but not SDM and the contacts look the same. There must be a difference in the internal electronics.

Regards
David

If you search for threads about the Kenko Pz-af 1.5X Teleplus SHQ. It works to a degree with SDM/HSM lenses, but it does a lot of hunting.

It's not hunting I was referring to Barrie, it's that the PZ-AF 2x TC will not even attempt to focus with Pentax SDM lenses. The cameras stay resolutely in Manual Focus mode.

Regards
David

I think that could be down to the fact that some converters were produced with the contacts in the bodies but no connection between front and back sets. As I understand it that's the difference in the SHQ and MC versions of the 1.5x.

Hi David - I was wrong about the 2X TC, so just to make things more confusing this is what I observed last night....

The Teleplus 2X PzAf MC7 does focus with screw drive lenses (no surprise) and attempts to focus with SDM lenses (DA*55) - but it does NOT focus at all with lens that have both systems (such as the DA*60-250 or DA*16-50), and as David experienced - it sets the display to MF.

I tried the Teleplus 1.5x PzAf MC - not the SHQ model - and it does focus with screw drive only (PAF), it does focus with SDM only and does focus with lenses that have both SDM/PAF. Although it does "hunt" a lot and doesn't always lock focus on the SDM only lenses.

These 2 TC's look very similar, all the contacts appear the same, yet they behave differently !

Thanks for this information John, it does seem very strange that it will focus with SDM only lenses but not those which also have screwdrive! You would think it would be the other way round.

Maybe someone with the appropriate technical knowledge can explain why this is the case. I do think the TC has all of the required contacts, but that there is probably a software issue somewhere that is preventing the focussing.

Regards
David