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08-04-2011, 09:51 AM   #16
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QuoteOriginally posted by excanonfd Quote
Littledrawe, you are in luck. I mounted a generic P67 to PK adapter to P67 SMC Takumar 300/4.0 and the AFA 1.7x to my K20D (I have no doubt the genuine Pentax P67 to P645 + p645 to PK adapter would work just as well, but they are buried deep in my Medium format bag). Set the camera to AF.s, manually focus the camera and half press the shutter and AF works quite well. Any subject within the same vicinity (+,- 50 feet) the AF works. Mind you it's very bright outside, in less than ideal conditions AFA 1.7x and an f4.0 lens do not work so well. I haven't checked the IQ but I've had good results with AFA 1.7x and other 300mm lenses.
This is good news! I don't have any medium format lenses on my radar right now but with the added compatability I might have to pull the trigger next time something comes along!

08-04-2011, 10:56 PM   #17
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QuoteOriginally posted by froeschle Quote
Have you really tried this? Communication between adapter and body is required for AF functionality (digital-info contact). Furthermore, one has to take care not to intervene with the auto-focus transmission shaft. So the other solution is not only more convenient but also less error-prone.
If you look at the diagrams in the links that you've provided, you can see where the contacts are on the body and on the lens. You don't need to cover all of the lens mount surface with foil, just where the body contacts will be when the lens is mounted. I have taken a non-infinity black aluminum m42 adapter, foil taped the contact portion of the mount and when used in conjunction with the AFA 1.7x adapter, AF works very well.

Place the adapter with the red dot at 12 o'clock position, the area that need to be covered by foil is between 4 and 6 o'clock position. Using a small piece of aluminum foil duct tape, trace and cut out the curves of the m42 adapter and carefully paste the duct tape in place. Burnish the tape with the edge of a plastic card to make sure the bond is strong and the the tape is as flat as possible. Screw the adapter on to an m42 lens and it's ready to go.

Thanks,

Last edited by excanonfd; 10-11-2011 at 11:39 AM.
08-05-2011, 12:53 AM   #18
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Thank you guys for all the valuable input!!!

Now, I have to find an AF adapter... missed one yesterday on fleabay, arrrgh!

BTW, the reason why I like the 6x7 4/400 with autofocus is that the focus barrel is so wide that I can barely turn it with one hand (I have small hands with short fingers, unfortunately, that't why I can handle a ME Super...)! And that does bring down manual focus speed so much that I can't use the lens for certain objects (like birds).
08-05-2011, 12:58 AM   #19
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QuoteOriginally posted by Vranx Quote
Thank you guys for all the valuable input!!!

Now, I have to find an AF adapter... missed one yesterday on fleabay, arrrgh!

BTW, the reason why I like the 6x7 4/400 with autofocus is that the focus barrel is so wide that I can barely turn it with one hand (I have small hands with short fingers, unfortunately, that't why I can handle a ME Super...)! And that does bring down manual focus speed so much that I can't use the lens for certain objects (like birds).
How much you offering???? I'm in anti-LBA mode at the moment.

08-05-2011, 02:25 AM   #20
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QuoteOriginally posted by cmohr Quote
How much you offering???? I'm in anti-LBA mode at the moment.
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