Canon FDn 70-210mm lock button stuck down?

bobotea · Aug 4, 2014

Hi guys, first post here and relatively new to cameras so please bare with me haha!

I recently bought a Canon FDn 70-210mm f4 lense off ebay for my Canon AE-1P, problem is when i try to mount the lens to the body it rotates fully into the correct position but the lock button does not "click" into place and seems to be stuck down. I was able to remove the lens with no problem and manually unlock the aperture to confirm the lens is in a working condition - which worked but even off the body the lock button does not "click" into its locked position when i rotate the inner ring to unlock the aperture. I have done the same manual off the body test with my FDn 50mm f1.8 (properly working lense) to confirm correct behaviour. My question to APUG is if anyone knows how i can fix the lock button, do i need to disassemble the lens (i have not done this before but am pretty technical)? or should i take it to a shop (i would prefer to do the fix myself if its not too difficult)?

Thanks

AgX · Aug 4, 2014

The correct "behaviour" of a NewFD lens is that the mount lock button is retracted when the lens is off and when it is twisted onto the camera Body. That button only jumps out at the end of the twist.

The mechanics of the mount at the lens are not too complicated. Dis-assembly is no problem. No Jack-out-of-box springs. However re-assembly (that SS flange) can be tricky.

There should be enough friction to arrest the lens in right position even without locking. So you might postpone repair to a very rainy day.

camtec · Aug 4, 2014

AgX is correct. Reassembly is very tricky.

CanonShot · Aug 5, 2014

Make certain that the locking ring is unlocked (turned completely counter- clockwise) and that the lens is properly aligned with the camera before mounting the lens on the camera.

benjiboy · Aug 5, 2014

CanonShot said:
Make certain that the locking ring is unlocked (turned completely counter- clockwise) and that the lens is properly aligned with the camera before mounting the lens on the camera.

He wrote the lens is an FDn they don't have locking rings.

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bobotea · Aug 6, 2014

thanks for the info guys, as stated before it is a FDn lens so it does not have the lock ring. I have made sure the lens is its in its original state (red dots lined up) before trying to mount onto the body - still no joy. The info is appreciated! but i am wondering if anyone has any specific info in regards to this exact problem or if they have seen this happen before, would there be a specific part i should replace or lubricate in the lens?

benjiboy · Aug 6, 2014

I wouldn't mess about with it for what it would cost I would get it repaired by a pro repairer, because what could be twenty minutes work for him could be a disaster if you attempted it.

AgX · Aug 6, 2014

I "repaired" a mount. That means I had to disassemble it to get the lens off the camera, after the preceeding owner brought it to the beach and 1 grain of sand got stuck in the female part. I don't remember in which position that knob was.

I did not look in detail at the lock mechanism, but I'm sure for anybody into mechanics any fault would be recognizable in short time.
But as that grain indicates there even not need to be any part faulty.

Ben, a repair likely would cost more than the lens.
If own attempts fail one still could bring it to a repair shop.

benjiboy · Aug 6, 2014

AgX said:
I "repaired" a mount. That means I had to disassemble it to get the lens off the camera, after the preceeding owner brought it to the beach and 1 grain of sand got stuck in the female part. I don't remember in which position that knob was.

I did not look in detail at the lock mechanism, but I'm sure for anybody into mechanics any fault would be recognizable in short time.
But as that grain indicates there even not need to be any part faulty.

Ben, a repair likely would cost more than the lens.
If own attempts fail one still could bring it to a repair shop.

I used to handle the repairs for a group of 10 camera stores and I know many repairers won't attempt to service equipment that has been tampered with by unskilled labour because often many components are missing and are a waste of their time, or he could alternatively throw it in the bin now, and save himself the trouble.

AgX · Aug 6, 2014

It depends on the repairer. If I can speak to the person (that means repair shop is in town) and describe the problem in detail and what I have done and what not, on my wording that person should be able to asses me and the problem.

You never repaired a camera, but not in all cases things end up in a heap of loose or missing parts.

benjiboy · Aug 7, 2014

AgX said:
It depends on the repairer. If I can speak to the person (that means repair shop is in town) and describe the problem in detail and what I have done and what not, on my wording that person should be able to asses me and the problem.

You never repaired a camera, but not in all cases things end up in a heap of loose or missing parts.

Every Saturday in my photographic store we used to get two or three middle aged men clutching plastic carrier bags full of camera or lens components from the equipment they had dismantled and pathetic expressions on their faces, but the repair companies we used wouldn't touch them they said they were more trouble than they were worth because they usually had components, springs and screws missing or had been damaged on dis-assembly.

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AgX · Aug 7, 2014

If I was a repairer and got a bag on my table full of parts and assemblies, I would be reluctant too.

benjiboy · Aug 8, 2014

As far as I'm concerned part of being a serious photographer is paying to have your equipment professionally maintained, rather than buying more and more cameras.

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AgX · Aug 8, 2014

Most of us are not serious photographers but Apuggers.

Canon FDn 70-210mm lock button stuck down?

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