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02-19-2012, 08:38 PM   #1
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Advice on Replacing the Lens Mount on a DSLR?

Thanks for the help, everyone!

Mount from an SF-1 was a perfect fit. The SF-1 has smaller contact points so smaller holes in the mount, but once you unscrew it and turn it around, there is some black plastic around the holes and once you take that off, it is a perfect fit.


Last edited by Julie; 03-05-2012 at 07:31 PM.
02-19-2012, 08:55 PM - 1 Like   #2
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Why not just pick up an AF film body to cannibalize? You can probably pick up an SF-1 for less than $30.

Check out shopgoodwill.com or craigslist.
02-19-2012, 08:57 PM - 1 Like   #3
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I don't know what other problems your body may end up having, but the mount ring from an '80s or '90s autofocus film SLR should have the same contact pattern and corresponding holes. The thickness or width of the mount ring may be a bit different - the mount ring on my MZ-5n is a bit narrower than the one on my K10. Many of the lower end SF series bodies don't sell for much over $10 and the low end MZ bodies don't go for much more .
02-19-2012, 09:07 PM   #4
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QuoteOriginally posted by boriscleto Quote
Why not just pick up an AF film body to cannibalize? You can probably pick up an SF-1 for less than $30.

Check out shopgoodwill.com or craigslist.
QuoteOriginally posted by Steinback Quote
I don't know what other problems your body may end up having, but the mount ring from an '80s or '90s autofocus film SLR should have the same contact pattern and corresponding holes. The thickness or width of the mount ring may be a bit different - the mount ring on my MZ-5n is a bit narrower than the one on my K10. Many of the lower end SF series bodies don't sell for much over $10 and the low end MZ bodies don't go for much more .
I feel really stupid right now... I had it in my head that the newer digital bodies should have more contacts because of the one for video, which the film-era AF cameras didn't have... Now I realized that the video ones must be the two gold contacts on the inside right. I went and counted on the K-r and compared that to an SF-1 on Ebay and yes, indeed, they do both have the same 7 points.

Thanks so much!
Now all I need is to find the right size/thickness. The one on my K-5 is much thicker (extra weather sealing so moisture doesn't bet between lens and camera, I'm guessing).

02-19-2012, 09:41 PM - 1 Like   #5
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You seem to know what you are doing. I'm not suggesting otherwise. But I think it is worth suggesting that whatever you do should be sturdy, so the lens doesn't fall off.

QuoteOriginally posted by Rodney Dangerfield:
It's been a rough day. I got up this morning, put a shirt on and a button fell off. I picked up my briefcase and the handle came off. I'm afraid to go to the bathroom.
02-19-2012, 09:58 PM - 1 Like   #6
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QuoteOriginally posted by Julie Quote
I feel really stupid right now... I had it in my head that the newer digital bodies should have more contacts because of the one for video, which the film-era AF cameras didn't have... Now I realized that the video ones must be the two gold contacts on the inside right. I went and counted on the K-r and compared that to an SF-1 on Ebay and yes, indeed, they do both have the same 7 points.

Thanks so much!
Now all I need is to find the right size/thickness. The one on my K-5 is much thicker (extra weather sealing so moisture doesn't bet between lens and camera, I'm guessing).
The two gold contacts inside the lens mount have nothing to do with video. They are the power supply contacts for the SDM lenses.

On older, film SLRs, such as the PZ series, they supplied power to the handful of power zoom lenses that Pentax made. The bonus is that, because the contacts are in the same place, power zooms will work on some Pentax dslrs. They work on my K10D, although not all power zoom functions are supported.
02-19-2012, 10:01 PM   #7
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QuoteOriginally posted by Aegon Quote
You seem to know what you are doing. I'm not suggesting otherwise. But I think it is worth suggesting that whatever you do should be sturdy, so the lens doesn't fall off.
Yes, I am keeping that in mind, that is why I'm going to scour Ebay for a broken/cheap 35mm AF body with a metal ring (I think I will pass on the ZX/MX cameras because I'm pretty sure they have plastic black rings), the same number or holes, and screws in the same places. Thank you.
02-19-2012, 10:05 PM   #8
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QuoteOriginally posted by noblepa Quote
The two gold contacts inside the lens mount have nothing to do with video. They are the power supply contacts for the SDM lenses.

On older, film SLRs, such as the PZ series, they supplied power to the handful of power zoom lenses that Pentax made. The bonus is that, because the contacts are in the same place, power zooms will work on some Pentax dslrs. They work on my K10D, although not all power zoom functions are supported.
Thank you very much for making that clear, so then what is the video linked to? One of the seven on the left?

02-19-2012, 11:31 PM   #9
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QuoteOriginally posted by Julie Quote
Thank you very much for making that clear, so then what is the video linked to? One of the seven on the left?
Why do you think video is linked to a contact? As far as I know, the K mount has not changed when with the K-7...
02-19-2012, 11:35 PM   #10
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Video is recorded by the sensor, processed by the camera and stored on the memory card. Whether you are recording video or taking still photos the mount and lens don't know the difference, so there was no need to change the mount to support video.

What sort of data were you expecting to be carried by extra contacts?
02-19-2012, 11:59 PM   #11
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QuoteOriginally posted by Julie Quote
Do you guys have any other ideas if the above two fail?
I am afraid it will be a futile exercise because all the plastic threads are stripped clean. Even if you managed to stick the mount back on, it won't be able to bear any weight. The only fix will be to replace the mirror box assemble which all other parts are attached to. It will be very costly because everything has to be rebuilt and re-calibrated from scratch. Also, a camera suffered from such impact is probably out of alignment too. It could be the prism, mirror or AF sensor. Personally I feel it's best to be stripped for parts.

Last edited by wlachan; 02-20-2012 at 12:52 AM.
02-20-2012, 02:32 AM   #12
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Go Check out www.keh.com they have a lot of old Pentax autofocus bodies for under $50

as to the screw hole, you could use 'lochtite' glue on the screw when you attach it (i've never tried it on a camera but have on machines)
02-20-2012, 09:23 PM   #13
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I am pretty sure that I have an old broken PZ1 or something laying around. Good source for a mount.
As for repairing the screw holes, there are many different types of glue available now. Go to a hobby shop - a good hobby shop - not Hobby Lobby. Find one that services the model railroader and has a good stock of plastic shapes and types. Take the camera and screws, get the sales person to help with the proper glue and plastic rods and even the proper size drill bits. You can drill the holes out in the camera and then glue in ABS plastic rods cut to the right length (the hobby shop can sell you a razor saw, if needed), then drill the rods to the correct size for the screws. Use a pin vice to drill the holes (the hobby shop will have a pin vice). Best that I can think of this late at night.
This all might be for naught. As mentioned above, things could be out of alinement. But...if I had this camera, I would try a repair, knowing not to get mad if things didn't go perfect.
02-20-2012, 10:29 PM   #14
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QuoteOriginally posted by Steinback Quote
The thickness or width of the mount ring may be a bit different - the mount ring on my MZ-5n is a bit narrower than the one on my K10.
Is it possible that the registration distance (distance from mount to sensor/film) is different between the film and digital bodies and instead of changing the lens mount, Pentax just changed the thickness of the mounting flange on the camera side when they went digital? If this is the case, a mount flange from a film body wouldn't work for you. I don't know if this really is the case but it's the first thing that popped into my head when I read the above quote. I thought I'd throw it out there before you put your money down on a parts (film) camera.
02-21-2012, 08:05 AM   #15
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QuoteOriginally posted by average-guy Quote
Is it possible that the registration distance (distance from mount to sensor/film) is different between the film and digital bodies and instead of changing the lens mount, Pentax just changed the thickness of the mounting flange on the camera side when they went digital? If this is the case, a mount flange from a film body wouldn't work for you. I don't know if this really is the case but it's the first thing that popped into my head when I read the above quote. I thought I'd throw it out there before you put your money down on a parts (film) camera.
Thickness of the mount is not going to be so much different that it would matter much, because the K-R has a AF adjustment. Even more AF adjustment is available in Debug mode through P-K Teather. After a camera was dropped, like this one was, a AF adjustment would seem mandatory.
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