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Arpe · 07-10-2007, 11:15 PM

Will the existing teleconverters, whether Pentax, Sigma or whatever, support SDM focussing? I presume it's just use of an existing electrical contact so I'm assuming yes, but does anybody know better?

barendvl · 07-11-2007, 06:23 AM

It's not just an existing electrical contact. The K100D has been updated to K100D super just to add the contacts for SDM support.

Look at this image:

The two contacts in the mount to the bottom right are for SDM.

So I presume that if a TC does not have wiring to connect those contacts to the lens, the SDM does not work on that SDM lens using a TC. However, normal AF will still work with an AF TC since the SDM lenses can also be incameramotor-driven.

Arpe · 07-11-2007, 05:04 PM

Bugger! More money to spend on new TCs then. I guess they'll take about 3 years to come out!

Timbuctoo · 07-11-2007, 05:38 PM

That's interesting, I thought that some of the older film Pentax cameras had those extra two contacts. It would be interesting to check the contacts in the AF teles already available and see if they have the two extra pins. I think the teles will work but you'll loose SDM performance.

07-10-2007, 11:15 PM	#1
Arpe Pentaxian Join Date: Sep 2006 Location: New Zealand Photos: Gallery \| Albums Posts: 4,452	SDM and TCs Will the existing teleconverters, whether Pentax, Sigma or whatever, support SDM focussing? I presume it's just use of an existing electrical contact so I'm assuming yes, but does anybody know better?

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07-11-2007, 06:23 AM	#2
barendvl Senior Member Join Date: May 2007 Location: Netherlands, Eindhoven Posts: 133	It's not just an existing electrical contact. The K100D has been updated to K100D super just to add the contacts for SDM support. Look at this image: The two contacts in the mount to the bottom right are for SDM. So I presume that if a TC does not have wiring to connect those contacts to the lens, the SDM does not work on that SDM lens using a TC. However, normal AF will still work with an AF TC since the SDM lenses can also be incameramotor-driven.

07-11-2007, 05:04 PM	#3
Arpe Pentaxian Join Date: Sep 2006 Location: New Zealand Photos: Gallery \| Albums Posts: 4,452 Original Poster	Bugger! More money to spend on new TCs then. I guess they'll take about 3 years to come out!

07-11-2007, 05:38 PM	#4
Timbuctoo Inactive Account Join Date: Feb 2007 Location: Darwin, Australia Posts: 203	That's interesting, I thought that some of the older film Pentax cameras had those extra two contacts. It would be interesting to check the contacts in the AF teles already available and see if they have the two extra pins. I think the teles will work but you'll loose SDM performance.

SDM and TCs

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