Canon LTM Messed up my 50mm 1.2

Canon M39 M39 screw mount bodies/lenses
JayC

JayC

5 kids,3 dogs,only 1 wife
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Jun 15, 2005
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543
I tried following the time lapse video instructions on youtoob for servicing this lens. Now I can’t get it back together correctly.
Where is a good place to send it to get put back together correctly and focusing like a dream.
Anyone on here wanna do it? 😃
 
Where are you stuck? I just opened mine up to clean it two days ago. Be careful with the rear elements, it is easy to screw one of the elements in backwards and it will go together fine but not focus properly.

Shawn
 
Don Goldberg at DAG camera repair seems to be the top repair guy in the USA...if you don't mind a long wait to get your fixed up lens back, I am sure other camera repair techs are just as capable and maybe faster and less expensive.
 
shawn said:
Where are you stuck? I just opened mine up to clean it two days ago. Be careful with the rear elements, it is easy to screw one of the elements in backwards and it will go together fine but not focus properly.

Shawn
Click to expand...

I am at the 8 minute mark in this video

https://youtu.be/e0U5gq-hKTc

Once I tighten the retaining ring down, the part it is retaining does not rotate anymore like it does in the video
 
It was a couple of years ago I took about the helicoid so don't remember the details in that section. Does the helicoid on the other side of that brass retained part intrude into that space at all or set the depth of that area? Doesn't look like it in the video but if it does I'd double check that all those parts are assembled properly. Helicoids can usually be threaded multiple ways but only one of them will be correct for the focusing to be correct.

Other than that I'd suggest walking away from it for a little while and come back with fresh eyes double checking all assumptions.

Good luck!

Shawn
 
Got it back together! Almost. There is a slight catchiness at one part of the focusing, but I can focus with just one finger now. ��
The video ends before showing how to put the infinity lock back on. All it is is a pin through the lock. That is the easy part. It is the placing of the spring underneath that makes no sense. In the video (very end of part 1 of his 2 videos), the spring is just laying in there it seems. That’s how it seemed mine was, but mine was perpendicular to the focal plane, his was parallel.

How to put it back together?
 
JayC said:
Got it back together! Almost. There is a slight catchiness at one part of the focusing, but I can focus with just one finger now. ��
The video ends before showing how to put the infinity lock back on. All it is is a pin through the lock. That is the easy part. It is the placing of the spring underneath that makes no sense. In the video (very end of part 1 of his 2 videos), the spring is just laying in there it seems. That’s how it seemed mine was, but mine was perpendicular to the focal plane, his was parallel.

How to put it back together?
Click to expand...


Good news, though I had been tempted to make an offer on it since I have a good mount with bad glass:)

The spring on mine looks to be on the pin itself, so parallel if I'm understanding.
 
Mark C said:
Good news, though I had been tempted to make an offer on it since I have a good mount with bad glass:)

The spring on mine looks to be on the pin itself, so parallel if I'm understanding.
Click to expand...

That makes the most sense. I have tried all ways to put the spring in that way. I used a needle to test fit things before putting the pin in. There is no tension in the spring. It just flops around. Makes no sense to me and I am really irritated that there is only one instructional video on the internet, it is very hard to follow, and leaves out this step.
 
Probably doesn't help but this is the spring in mine.

50203241796_59f772fa18_b.jpg


Any chance it is a torsion spring, not used as a compression spring? If so you might have to pre-tension it as you are installing it.

Shawn
 
shawn said:
Probably doesn't help but this is the spring in mine.

...

Any chance it is a torsion spring, not used as a compression spring? If so you might have to pre-tension it as you are installing it.

Shawn
Click to expand...


Looks like mine. I assumed it will need to be tensioned. Sounds tricky to me.
 
Yes, it is a torsion spring. There is no place to "hook" it. It appears to have to be put under tension by hand, then the infinity lock placed over it holding it in place, then there is a small pin that goes through the lock button and the spring to hold the 2 pieces to the lens body. Seems impossible.
In taking it apart, the spring did not fly out at me. It didn't do that in the repair video either. The spring just acted as if it was gently laid in there. Once the retaining pin was removed, you would think the spring would release and the lock button and spring would fly off and the spring would never be found again.

I guess I need to set up a 20'x20' work area of pure white, so that when the spring goes popping I can find it to try again.
 
For those that find this thread in the future. I figured it out and my lens is whole again. It took many days and many different ideas.
Tip #1
Don’t take off the infinity lock. Don’t even think about it. It does not need to be removed to service the lens.
Tip #2 (If you missed tip #1)
You will need a small paper clip, a wire cutter to cut the paper clip to length, and an enclosed space such as a shower stall. Make sure to tape over the shower drain so the flying tiny spring stays confined in your safe workspace.

Cut the paper clip just long enough to hold the spring in the flange that is on the lens. The thumb button must be able to go over the flange with the paper clip in place. Put the spring under tension so both ends are pointed towards the front of the lens. Hold there with the tip up your thumb while you place the thumb button over the set up.
Now, hold it all together while you push in the correct pin. You will use the correct pin to replace/push out the paper clip. This method only took me a couple of attempts to succeed.
I honestly don’t think there is any other way to do it.
 
It helps to have all of the parts. How many infinity locks have been disabled because the spring flew off and disappeared? Kudos for perseverance.
 
JayC said:
Yes, it is a torsion spring. There is no place to "hook" it. It appears to have to be put under tension by hand, then the infinity lock placed over it holding it in place, then there is a small pin that goes through the lock button and the spring to hold the 2 pieces to the lens body. Seems impossible.
In taking it apart, the spring did not fly out at me. It didn't do that in the repair video either. The spring just acted as if it was gently laid in there. Once the retaining pin was removed, you would think the spring would release and the lock button and spring would fly off and the spring would never be found again.

I guess I need to set up a 20'x20' work area of pure white, so that when the spring goes popping I can find it to try again.
Click to expand...

I prefer to use this device when disassembling lenses. I call it the "Cone of Camera Lens Annoyance" :)

My problem when I come to reassemble my lenses is now not that I have too few small parts. It's that I have too many - with some left over. :(

Get_Smart-Cone-of-silence.jpg
 
If you put a rare earth magnet over the spring the odds of it going flying off drop to almost zero. And if it does, the odds of finding it go way up if you use the REM to sweep the area in order to find it. A strong magnet will find the spring even if you only get close to it. Same goes for screws, unless they are brass of course.
 
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