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12-31-2007, 04:13 AM   #1
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Kenko TCs (mc7) PzAF won't autofocus with DA*/SDM

I have just got a new Kenko TCs (mc7) marked PzAF, it does not work with DA* lens. No screw autofocus and no sdm, the DA* just becomes a manual focus len.
Luckily, I am not buying that TCs for serving my DA*. But for those thinking to buy a PzAf TCs for matching DA* and sdm will work, please be awared.
Or may be a firmware update would makes the combination workable?
Happy new year.

12-31-2007, 06:52 AM   #2
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The most interesting question is:
Why does it not work?
If all contacts are connected through, it should work, right?
12-31-2007, 07:38 AM   #3
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If there is no screw drive and no power contacts for HSM then it is probably a KA mount TC.

How many contacts are on the mount face for the lens 6 or 7. If the answer is 6 then it is actually a KA mount. if the answer is 7 then it does feed lens data, focal length, focusing distance etc to the camera, just not auto focus.
12-31-2007, 09:02 AM   #4
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Well, I think Kenko might have two versions PzAF 2x MC7.
I just have a check and finds out mine is the same model as Pic1 with 6 pins on the mount face towards the camera.
Really, there is another version with 7 pins as shown in Pic2 and Pic3. However, I have no idea whether the 7 pin one can enable AF/SDM with DA* or not.
May be someone could confirm this?

Pic1


Pic2


Pic3


12-31-2007, 09:14 AM   #5
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My DA* lenses also have 6 pins only.
This should not be a problem (for DA* lenses).

I am wondering if the pin definition is still the same as that given on Bojidar's page.
12-31-2007, 12:41 PM   #6
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QuoteOriginally posted by dsport Quote
I have just got a new Kenko TCs (mc7) marked PzAF, it does not work with DA* lens. No screw autofocus and no sdm, the DA* just becomes a manual focus len.
Luckily, I am not buying that TCs for serving my DA*. But for those thinking to buy a PzAf TCs for matching DA* and sdm will work, please be awared.
Or may be a firmware update would makes the combination workable?
Happy new year.
I suspect that the adapter is telling the k10d that the lens is SDM, and then the camera will try to focus with the in lens motor rather than the screw drive. Perhaps someone could come up with a map as to which of the adapter pins to disable to not tell the camera it's a DA* lens - then you could treat it as a manual lens and use it that way.
12-31-2007, 12:52 PM   #7
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QuoteOriginally posted by Canada_Rockies Quote
I suspect that the adapter is telling the k10d that the lens is SDM, and then the camera will try to focus with the in lens motor rather than the screw drive.
And what is the problem with this?
The SDM contacts are there.
12-31-2007, 01:04 PM   #8
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QuoteOriginally posted by blende8 Quote
And what is the problem with this?
The SDM contacts are there.
They are power zoom contacts that have been co-opted by Pentax, so you are correct! The converter is NOT telling the camera that it is DA*. Oops!

12-31-2007, 01:45 PM   #9
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there should be nothing wrong with the TC and it should focus

The missing pin is part of the grey scale coding for apature values and does not affect focusing distance information back to the camera.

when you say that it does not focus, what do you mean, no focusing at all, i.e. you can't hear the focusing motor? or it won't lock on focus.

Note that for a 2 x TC to focus, you need a prime lens faster than F3.5

the pin that relays information on focusing distance is the 7th pin away from the lens locking pin. the missing pin on your adaptor is the second. Note, the third pin from the locking pin is recessed on the side where the lens mounts. This pin if it touoches the lens base (or a pin connected to the lens base, tells the camera that the lens is in auto apature mode
12-31-2007, 02:34 PM   #10
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QuoteOriginally posted by Lowell Goudge Quote
there should be nothing wrong with the TC and it should focus

The missing pin is part of the grey scale coding for apature values and does not affect focusing distance information back to the camera.

when you say that it does not focus, what do you mean, no focusing at all, i.e. you can't hear the focusing motor? or it won't lock on focus.

Note that for a 2 x TC to focus, you need a prime lens faster than F3.5

the pin that relays information on focusing distance is the 7th pin away from the lens locking pin. the missing pin on your adaptor is the second. Note, the third pin from the locking pin is recessed on the side where the lens mounts. This pin if it touoches the lens base (or a pin connected to the lens base, tells the camera that the lens is in auto apature mode
Well, no focusing at all. Also, the viewfinder shows the sign of 'MF'.
Strange...
12-31-2007, 06:56 PM   #11
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Pretty sure I tried the Kenko 1.5 tele converter with the DA* and it focused fine in SDM. Reason for pretty sure is I have a very similar Promaster 1.7 converter (must be made by same company - styling is the same) and I could have grabbed it instead. The Kenko will not meter properly with my Pentax A400 5.6 lens. For some reason it has a different # of contacts on the front than the back! The Promaster has equal # of contacts front & rear and works with 5.6 lenses! Strange.
thanks
barondla
12-31-2007, 10:18 PM   #12
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QuoteOriginally posted by barondla Quote
Pretty sure I tried the Kenko 1.5 tele converter with the DA* and it focused fine in SDM. Reason for pretty sure is I have a very similar Promaster 1.7 converter (must be made by same company - styling is the same) and I could have grabbed it instead. The Kenko will not meter properly with my Pentax A400 5.6 lens. For some reason it has a different # of contacts on the front than the back! The Promaster has equal # of contacts front & rear and works with 5.6 lenses! Strange.
thanks
barondla




Your Kenko 1.5 tele converter is the same one as the above pics?
It only has 6 pins on the back just same with my kenko 2x, but then it still work with sdm and meter properly?
As blende8 pointed out, may be pin definition had something been changed
01-01-2008, 02:57 AM   #13
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Just have a look in the Japanese site of Kenko
ƒPƒ“ƒR[ ƒeƒŒƒvƒ‰ƒXDG
Officially, for Pentax it stated as
"It does not correspond to the lens "SDM" of the motor inside the lens. But because there is a contact point "of power zoom", the motor moves. (As for focus it is not agreeable) we ask with use with manual focusing."
I use the translation software to have the above readings. So no SDM support for their current version. May be the previous version as shown in my Pic1/Pic2 could.
01-01-2008, 06:47 AM   #14
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Looks like my Kenko. I would try it on the SDM lens but that wasn't my lens. Still don't understand why a company would go to the trouble to build 7 contacts on front of converter and then have only 6 on the back. If redesigning it why not get rid of extra front contact? Why have spring loaded contacts go no where? Why not use the same mounts as the Promaster - same company built both. My Kenko is barely 1 yr old. Just checked out a new one its also missing a pin. Strange.
thanks
barondla
01-05-2008, 06:49 AM   #15
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I now have a Kenko Uniplus Tube 25, no converter, but a tube.
It is available used only these days.

It works both, shaft-driven AF and SDM-AF!

The tube looks like this:



I measured the distance from SDM contact to bajonet surface.
It is 7.9 mm for the converter
and
it is 8.2 mm on the 50-135 DA* lens.
So only 0.3 mm to impress the contacts.
If now there is a little variation in this distance it is possible that no contact can be established.
Just a speculation ...
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