Advice on Replacing the Lens Mount on a DSLR?

Julie · 02-19-2012, 08:38 PM

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.

**boriscleto** · 02-19-2012, 08:55 PM - **1 Like**

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.

Steinback · 02-19-2012, 08:57 PM - **1 Like**

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 .

Julie · 02-19-2012, 09:07 PM

Originally posted by boriscleto

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.

Originally posted by Steinback

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).

Aegon · 02-19-2012, 09:41 PM - **1 Like**

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.

Originally 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.

noblepa · 02-19-2012, 09:58 PM - **1 Like**

Originally posted by Julie

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.

Julie · 02-19-2012, 10:01 PM

Originally posted by Aegon

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.

Julie · 02-19-2012, 10:05 PM

Originally posted by noblepa

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?

Zav · 02-19-2012, 11:31 PM

Originally posted by Julie

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...

Steinback · 02-19-2012, 11:35 PM

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?

wlachan · 02-19-2012, 11:59 PM

Originally posted by Julie

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.

bdparker · 02-20-2012, 02:32 AM

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)

gp1806 · 02-20-2012, 09:23 PM

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.

average-guy · 02-20-2012, 10:29 PM

Originally posted by Steinback

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.

gp1806 · 02-21-2012, 08:05 AM

Originally posted by average-guy

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.

02-19-2012, 08:38 PM	#1
Julie Veteran Member Join Date: Aug 2010 Location: Illinois Photos: Gallery \| Albums Posts: 1,069	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, 11:59 PM	#11
wlachan Veteran Member Join Date: Sep 2006 Location: Canada Photos: Albums Posts: 2,625	Originally posted by Julie 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.

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02-19-2012, 08:55 PM - 1 Like	#2
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	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
Steinback Veteran Member Join Date: Jan 2008 Location: GTA, ON, Canada Photos: Gallery \| Albums Posts: 1,673	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
Julie Veteran Member Join Date: Aug 2010 Location: Illinois Photos: Gallery \| Albums Posts: 1,069 Original Poster	Originally posted by boriscleto 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. Originally posted by Steinback 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
Aegon Site Supporter Join Date: Jan 2008 Location: Portland, OR Posts: 1,416	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. Originally 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
noblepa Veteran Member Join Date: Sep 2007 Location: Bay Village, Ohio USA Posts: 1,142	Originally posted by Julie 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
Julie Veteran Member Join Date: Aug 2010 Location: Illinois Photos: Gallery \| Albums Posts: 1,069 Original Poster	Originally posted by Aegon 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
Julie Veteran Member Join Date: Aug 2010 Location: Illinois Photos: Gallery \| Albums Posts: 1,069 Original Poster	Originally posted by noblepa 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
Zav Pentaxian Join Date: Feb 2009 Photos: Gallery Posts: 1,371	Originally posted by Julie 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
Steinback Veteran Member Join Date: Jan 2008 Location: GTA, ON, Canada Photos: Gallery \| Albums Posts: 1,673	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?

02-20-2012, 02:32 AM	#12
bdparker Veteran Member Join Date: Sep 2011 Location: Melbourne Photos: Gallery \| Albums Posts: 307	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
gp1806 Veteran Member Join Date: Mar 2009 Location: Chicago suburbs Photos: Albums Posts: 848	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
average-guy Senior Member Join Date: Dec 2010 Location: Idaho Posts: 102	Originally posted by Steinback 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
gp1806 Veteran Member Join Date: Mar 2009 Location: Chicago suburbs Photos: Albums Posts: 848	Originally posted by average-guy 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.