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07-20-2012, 08:14 AM   #1
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Help fixing focus on S-M-C Takumars

I have two S-M-C Takumars with focusing issues.

- One Asahi S-M-C Takumar 85mm/1.8 that which focus stop a bit before infinity.
- One Asahi S-M-C Takumar 50mm/1.4 that seems out of focus, is the only lens for which I need to adjust viewfinder diopter.

Any suggestions/ideas how to fix this? I have taken apart one Super-Takumar and on old Pentacon before, but I'm a bit afraid to play experiment with the ones above, I want to be sure I cant put them back together again

07-20-2012, 08:58 AM   #2
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Do you use the right m42 to K mount adapter?
07-20-2012, 12:43 PM   #3
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QuoteOriginally posted by Vasyl Quote
Do you use the right m42 to K mount adapter?
No, M42 to EOS
07-20-2012, 01:08 PM   #4
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QuoteOriginally posted by Retrocamera.net Quote
No, M42 to EOS
Kidding? The reason asking is because some of them don't allow infinity focus...

07-20-2012, 01:32 PM   #5
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QuoteOriginally posted by vonBaloney Quote
Kidding? The reason asking is because some of them don't allow infinity focus...
No really, I use a lot of manual lenses (M42 and Contax/Yashica) on Canon EOS 60D. Many of them are Takumars in different versions.

The 85mm is far from infinity, and the previous 85mm from Asahi (Auto-Takumar, Super-Takumar) has all worked with the same adapter + camera.
07-20-2012, 01:45 PM   #6
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I've never taken apart the 85mm (or seen one up close), but if they are like most of the other Takumars infinity-focus adjustment is pretty easy. Remove faceplate with friction tool. Remove filter ring (a few screws), find the screws that lock down the focus placement (they will be half on outer focus ring, and there will be other screws set more inward -- leave those alone), make sure it is set at infinity already, loosen those screws, adjust ring slightly as needed, tighten again (just enough to hold), check focus on camera, repeat as necessary, do final tightening, put back filter ring and faceplate.

In order to get proper adjustment, you really should make sure you're using a native m42 mount camera or genuine adapter on a K-mount. However, maybe you only care to make it work on your set-up -- which is how I think some of these lenses get out of whack in the first place...
07-20-2012, 01:46 PM   #7
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QuoteOriginally posted by Retrocamera.net Quote
I have two S-M-C Takumars with focusing issues.

- One Asahi S-M-C Takumar 85mm/1.8 that which focus stop a bit before infinity.
- One Asahi S-M-C Takumar 50mm/1.4 that seems out of focus, is the only lens for which I need to adjust viewfinder diopter.

Any suggestions/ideas how to fix this? I have taken apart one Super-Takumar and on old Pentacon before, but I'm a bit afraid to play experiment with the ones above, I want to be sure I cant put them back together again
I have read all the comments but decided to quote this one because there are some interesting points

if you need to adjust the viewfinder diopter for the SMC Tak 50/1.4 then you need to adjust it for all lenses because the focusing screen is just that, a screen that the image is projected onto, if it is out of focus for any one lens it is out of focus for all of them. period.,

as for the 85/1.8 it could be that the focusing collar, which limits infinity focus, has slipped on the focusing helix. Assuming it is like my 85/1.9 super tak, you can remove the front beauty ring to expose 3 screws that hold by friction of the washers under their heads, the focusing collar to the helix these could have slipped. do a search on the forum and you may find a photo of how to adjust this.
07-20-2012, 09:40 PM   #8
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QuoteOriginally posted by Lowell Goudge Quote
if you need to adjust the viewfinder diopter for the SMC Tak 50/1.4 then you need to adjust it for all lenses because the focusing screen is just that, a screen that the image is projected onto, if it is out of focus for any one lens it is out of focus for all of them. period.
Could be that I only notice it when at f1.4. I'll give it a try with my tripod to be shure.


Last edited by Retrocamera.net; 07-20-2012 at 09:45 PM. Reason: Adding a sentence
07-20-2012, 09:43 PM   #9
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QuoteOriginally posted by vonBaloney Quote
In order to get proper adjustment, you really should make sure you're using a native m42 mount camera or genuine adapter on a K-mount. However, maybe you only care to make it work on your set-up -- which is how I think some of these lenses get out of whack in the first place...
Thanks! I will give it a try.
No problem, I also have a shelf full of M42-camera including a very nice Spotmatic
07-20-2012, 09:54 PM   #10
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QuoteOriginally posted by Retrocamera.net Quote
Thanks! I will give it a try.
No problem, I also have a shelf full of M42-camera including a very nice Spotmatic
Test the spotmatic with a lens you know to be properly aligned to see if infinity focus looks right in the viewfinder. I have one that makes all lenses look like infinity is off, but it is just the viewfinder...
07-21-2012, 05:58 AM   #11
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QuoteOriginally posted by Lowell Goudge Quote
if you need to adjust the viewfinder diopter for the SMC Tak 50/1.4 then you need to adjust it for all lenses because the focusing screen is just that, a screen that the image is projected onto, if it is out of focus for any one lens it is out of focus for all of them. period.,
QuoteOriginally posted by Retrocamera.net Quote
Could be that I only notice it when at f1.4. I'll give it a try with my tripod to be shure.
I repeat. The focusing screen is a screen the image is projected onto. You focus with the eyepiece on the screen, and the image projected on the screen, not through the entire optic to the subject. To adjust the eyepiece diopter, focus it on the markings, and that should have everything in focus.

Note, the focusing screen h more depth of field than any lens faster than about F4 because it is optimized for consumer lenses. A 50/1.4 has such a narrow DOF that you can be fooled by the focusing screen into thinking it is in focus when it is not. Also, to confuse the matter further some fast lenses exhibit a slight focus shift when stopped down, however that should be offset by the increased DOF in general
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