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03-08-2021, 08:25 PM   #1
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Super Takumar 50mm f1.4 (8 elements) problem with helicoid assembly

I just bought the 8 elements Super Takumar 50mm f1.4 and sadly it has problem on it's mechanical parts, the focus ring is loose and it doesn't focus to infinity. I used a Sony A55 btw. As I tried to open the lens to fix the focusing mechanism, I set the focus ring to infinity before removing the casing and the helicoid and marked it. I also marked the brass ring where it should focus to infinity, then I rotate the brass ring in clockwise 7 times until it comes off and cleaned it and the helicoid. After applying lubrication on both the brass ring and the helicoid and tried to assemble it aligning all the marks I have done and put back the outer casing I noticed that the minimum focusing distance only stop in between of 0.5 and 0.45 on the meter distance scale of the focus ring. As I disassemble it to look for what causing it, I noticed that the 2 brass retainer that prevents the helicoid from spinning is the culprit. The 2 brass retainer touches the brass ring before it reach the minimum focusing distance of 0.45m. My question is, are there any lapses from my way of disassembling this lens? I can't find a detailed disassembly of this particular lens on the internet. Any help would be very much appreciated. Thanks

03-08-2021, 09:16 PM - 3 Likes   #2
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When I had similar alignment problems when working with various lenses(years ago)-and they did align correctly on re-assembly, I would rotate the pieces till the next thread entry position and try again.
You may have to do this 10 or 20 times, depending on how many threads are cut into the helix.

It sounds like that one has been apart before and reassembled one or two (or more) threads out of the correct orientation.
03-08-2021, 09:44 PM - 2 Likes   #3
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QuoteOriginally posted by DonV Quote
When I had similar alignment problems when working with various lenses(years ago)-and they did align correctly on re-assembly, I would rotate the pieces till the next thread entry position and try again.
You may have to do this 10 or 20 times, depending on how many threads are cut into the helix.

It sounds like that one has been apart before and reassembled one or two (or more) threads out of the correct orientation.
You're right. The entry points on this have 6 threads. And I forgot I successfully manage to reach the 0.45m minimun focusing distance but there's a catch, the screws that holds the focus ring and brass ring tend to bite unto the brass ring when it nearly reaches the 0.45m focus distance. Same with the screws that holds the filter rings. I've done this since last night for many times, and yes I still be able to keep my sanity from doing this, wish me luck.
03-09-2021, 07:01 AM   #4
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Best of luck!
Are the screws too long or the heads the wrong shape?
Perhaps they are not the original screws and/or put into the wrong spot- perhaps switching locations or judicious filing would be in order to eliminate the "catch".

I'm sure you have demonstrated enough patience to overcome the glitch!

03-11-2021, 11:08 PM   #5
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QuoteOriginally posted by DonV Quote
Best of luck!
Are the screws too long or the heads the wrong shape?
Perhaps they are not the original screws and/or put into the wrong spot- perhaps switching locations or judicious filing would be in order to eliminate the "catch".

I'm sure you have demonstrated enough patience to overcome the glitch!
Found it! finally. The two brass retainers that holds the helicoid are put in reversed that's why it grinds into the brass ring when it reach the near minimum focus distance. Thank God I nearly gave up on this assembly. My only regret is I filed the filter ring screws and the brass retainers to make it a little short hoping it will solve the problem.
03-12-2021, 06:42 AM - 1 Like   #6
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Now ... please take photos of the process of re-assembling and upload these!

Very valuable to others.

I don't think we have the 8-Element in the list?!
03-14-2021, 09:50 PM - 4 Likes   #7
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03-15-2021, 07:42 AM - 1 Like   #8
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Super post; thanks for taking the time!

03-15-2021, 07:48 AM - 1 Like   #9
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Thank you for presenting your procedure.

Making witness marks is a key step in disassembly -- especially the helicoid!

- Craig
03-15-2021, 09:24 AM - 1 Like   #10
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Thanks a lot for up-loading the photos.
I have myself 2 of those lenses and like them very much. So in case disassembly is needed, this is more than helpful!

You uploaded them twice, did you realize?
The second 14 photos with the option for viewing EXIF Datas.
03-15-2021, 07:35 PM - 1 Like   #11
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QuoteOriginally posted by photogem Quote
Thanks a lot for up-loading the photos.
I have myself 2 of those lenses and like them very much. So in case disassembly is needed, this is more than helpful!

You uploaded them twice, did you realize?
The second 14 photos with the option for viewing EXIF Datas.
I'm new in this forum and didn't know that "manage attachments" are also included in posting, can't find an option to edit but anyways Thank a lot
03-15-2021, 10:36 PM - 1 Like   #12
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It doesn't really matter.
The best is to create a photoalbum and upload the photos there.
Then you integrated them from there into your post.

If you have photos of the assembly, would be good as well.
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50mm, 8 element st 50mm 1.4, brass, camera, distance, elements, focus, helicoid, infinity, lens, pentax help, photography, retainer, super takumar 50mm f/1.4, takumar 50mm f1.8, troubleshooting
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