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07-19-2010, 07:11 PM   #1
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HSM teleconverters

Has any one tried the Bower / vivitar 7 element teleconverters being sold by B&H.

I can only assume they are made by samyang like all the rest of the bower/vivitar lenses, but what is interesting is the bower one is actuallly photographed as the pentax mount, and shows Pentax PZ on the side, implying it is the origonal KAF2 mount?

Does it work with SDM and what is the aperture reporting???

07-19-2010, 09:51 PM   #2
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QuoteOriginally posted by Lowell Goudge Quote
Has any one tried the Bower / vivitar 7 element teleconverters being sold by B&H.

I can only assume they are made by samyang like all the rest of the bower/vivitar lenses, but what is interesting is the bower one is actuallly photographed as the pentax mount, and shows Pentax PZ on the side, implying it is the origonal KAF2 mount?

Does it work with SDM and what is the aperture reporting???
Lowell, did you post this question in the B&H Q&A section? I'll bet they can give you a definitive answer. I think we'd all be interested, too.
07-19-2010, 11:29 PM   #3
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I don't know for sure, because I've never used them. But I bet you in terms of interface with SDM and aperture/focal length reporting, they are not any better than the Tamron 1.4X TC or the Kenko 1.5X TC. If you're referring to the 2X TC, I don't think they can autofocus with SDM lenses at all.
07-20-2010, 05:18 AM   #4
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QuoteOriginally posted by Biro Quote
Lowell, did you post this question in the B&H Q&A section? I'll bet they can give you a definitive answer. I think we'd all be interested, too.
good point, but I was looking for user input too

07-20-2010, 05:24 AM   #5
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QuoteOriginally posted by SOldBear Quote
I don't know for sure, because I've never used them. But I bet you in terms of interface with SDM and aperture/focal length reporting, they are not any better than the Tamron 1.4X TC or the Kenko 1.5X TC. If you're referring to the 2X TC, I don't think they can autofocus with SDM lenses at all.
why would a 2x TC not autofocus on a F2.8 lens??? surely any camera can autofocus with a combined aperture of F5.6

As for the other issues, That is some of the specific data I was looking for, there is no difficulty mapping through a PGA the aperture coding to correct for the TC, after all pentax do this on the SMC-F 1.7x AF TC.
07-20-2010, 06:34 AM   #6
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I can confirm that the Kenko made 7 element 2x TC will not work with any of my SDM lenses even thought it has the power zoom contacts.
07-20-2010, 11:46 AM   #7
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QuoteOriginally posted by Lowell Goudge Quote
why would a 2x TC not autofocus on a F2.8 lens??? surely any camera can autofocus with a combined aperture of F5.6
Beat me! All I know is my Tamron 2X TC with power contacts does not work at all with any of the SDM zooms lenses I have. It works fine with lenses with screw-drive autofocus, however (provided the lens is fast enough).

My Tamron 1.4X TC with power contacts does not work reliably with SDM zoom lenses, in particular at the long end of the focal length, despite the effective aperture of F/4 (e.g. with the DA* 50-135).
07-20-2010, 01:44 PM   #8
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QuoteOriginally posted by SOldBear Quote
Beat me! All I know is my Tamron 2X TC with power contacts does not work at all with any of the SDM zooms lenses I have. It works fine with lenses with screw-drive autofocus, however (provided the lens is fast enough).

My Tamron 1.4X TC with power contacts does not work reliably with SDM zoom lenses, in particular at the long end of the focal length, despite the effective aperture of F/4 (e.g. with the DA* 50-135).
It may be that there is electronics in between the data pin, to be compliant to the PZ 1 standard, which does not understand the SDM command set

This is where sometimes a smart TC is a liability because it cannot be reprogrammed if the communications interface or data changes.

I think a while back I read something about this and a forum member took the electronics out and bypassed it.

07-20-2010, 02:00 PM   #9
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Kenko MC7 DG - NO power contacts.

I saw the Kenko MC7 pictures and reviews and assumed they worked with motorised AF lens. The ones in the database have Pz AF against them and seem to have power contacts on the lens side. I can definitely confirm that the one sold in the UK with the DG logo has power contacts on the camera side, but NO contacts on the lens side. So they will NOT operate motorised AF lens. Also they show P AF on them.

Why Kenko appeared to have built a TC with lens power contacts and then, I believe the latest one the DG not to have them seems a mystery to me.
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