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10-26-2011, 01:25 PM   #1
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lubricating Takumar F/1.4 50mm

Hi All,

I recently acquired a SMC Takumar F/1.4 50mm and it appears to be in good shape overall, except the focus is very stiff. So much that the lens actually unscrews itself from the camera at time as I try to twist the focus ring - definitely not right. I've contacted the seller to seek a return, but also thinking ahead to my options if that doesn't pan out.

My guess is that re-lubricating the lens would solve this. Any thoughts on this - is this a common issue? How difficult is it to re-lubricate this lens?

I've looked through the dis-assembly steps outlined by Just1MoreDave here: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/135293-s-m-c-t...e-problem.html. Looks do-able, but once taken apart is there access to the entire focus assembly area (all the 'threads')?

If anyone has done this before I would really appreciate any advice.

10-26-2011, 03:43 PM   #2
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QuoteOriginally posted by peated Quote
...If anyone has done this before I would really appreciate any advice.
The first time I unscrewed the focus helix, I did not know how difficult it would be to get it back together. It's like a mechanical puzzle. The threads aren't like a typical screw that starts at one point; there are sometimes six entry points. Only one starting point gets everything lined up properly. The only way I know to reassemble the lens is trial and error. So one possible advisement is "No, don't do it!"

With some care you might be able to avoid completely unscrewing the helix. First, focus the lens to infinity then to the minimum distance, noting how far the focus ring must turn to do that. I think it's 180 degrees. Leave it at the minimum distance. Disassemble the lens by removing the trim ring, filter ring, and focus ring. Clean off the old grease. Use a cotton swab to apply a small amount of mineral spirits to the exposed focus threads, turn the brass ring counter-clockwise about the same amount as you discovered in the first step, then clockwise the same amount. Clean off the threads again and repeat until they are mostly clean. Then regrease them and see if focus has improved.

That might not work because it's harder to get the threads entirely clean that way, and there are threads you can't access without further disassembly*. But I think it's worth a shot to avoid the mechanical puzzle. If the lens is still hard to focus, you'll have to turn the brass ring until the helix separates. It's a good idea to do this slowly to feel the exact moment of separation, then note where the brass ring is and everything else. It might help get everything back in place without the guessing. There may be copper guide bars that keep the elements from rotating when focusing. You may find it's easier to keep them installled when reassembling, or remove them and install them afterwards.

*Here's a photo of a Pentax lens showing the thrads you can't see at first. The aluminum ring here is the same as the brass ring in your Takumar. It is threaded with coarse threads inside to match with the focus helix, and fine threads outside and under a rim to attach to the lens body.
10-26-2011, 09:49 PM   #3
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Dave,

Thanks for the detailed explanation and words of warning. I don't think I want to tackle to focus helix unless I am out of other options. Luckily, the seller is willing to take this lens back so I will try my luck with another one (another seller that is - I still do want the Takumar 50mm 1.4!).

Reading through your lens repair tips, one question struck me. It might be obvious, but what precautions do you take to protect the glass surfaces when working on a lens? Just extra care not to touch, or do you cover the elements with something?
10-27-2011, 02:14 AM   #4
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Good that you have returned the lens. I've had ~50 Takumars, and none of them had stiff focusing because Asahi used the best combination of tolerances and grease. Even today most of my Takumars do not have any play or stiff focusing. I think your example was stored in much less than desirable conditions. Especially the 50mm f/1.4 Takumar should have a smooth focus.

I consider the late Takumars among the best ever made, mechanically.

10-27-2011, 09:28 PM   #5
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QuoteOriginally posted by peated Quote
Dave,

Thanks for the detailed explanation and words of warning. I don't think I want to tackle to focus helix unless I am out of other options. Luckily, the seller is willing to take this lens back so I will try my luck with another one (another seller that is - I still do want the Takumar 50mm 1.4!).

Reading through your lens repair tips, one question struck me. It might be obvious, but what precautions do you take to protect the glass surfaces when working on a lens? Just extra care not to touch, or do you cover the elements with something?
Just extra care. I sometimes deliberately put a fingerprint on the outer surface of lens elements I've disassembled, if there's any chance they will go in backward. Once it's in the correct way I clean the print off.
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