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pochini
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 10, 2005 - 12:56 am: | 
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I have a 200mm macro lens which has some play in the focusing ring. Do anyone know how to disassemble the beast without killing it ? I think it should be disassembled from the mount side because the front lens is as large as the barrel and I can't see any screw or any other dismountable things inside. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 10, 2005 - 07:49 am: |
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Specify which 200mm lens this is,so that correct instructions can be given. |
pochini
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 11, 2005 - 08:21 am: |
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Only one type of FD 200mm macro lens was made AFAIK. It's f/4.0 new-FD mount: http://www.canon.com/camera-museum/camera/lens/nfd/data/nmfd_200_4.html |
pochini
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 11, 2005 - 08:24 am: |
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Oops, I didn't write "FD" in my first message  I was sure I did, sorry. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 11, 2005 - 10:41 am: |
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So this is the 'True'macro lens,which raises small problem.It is one of the few nFD lenses that I do not have the official microfiche for.From what details I have,would say that lens does strip from front,either fully or partially.Only references to rear are for general assembly of mount etc,ie removal of the 3 screws will allow female bayonet ring and actuating assembly to be removed.Removing 3/4 internal screws will then allow removal of aperture ring and rear portion of lens holding lock button.If I remember correctly the front element is retained by a threaded ring.
What is mentioned in the general repair details is the fact that at minimum focus,the inner and outer helicoid are barely engaged.Mention is then made of the requirement to get the correct feel in the helicoid.This is evidently done by mixing different grades of damping grease,in varying proportions.If this is not done correctly, then slop and wear will be rapid.
This lens was the only FD item that gave us trouble when subjected to the rigors of a working environment-rapid wear/play in the focus mechanism.We eventually sent the replacement back also.Hence it is not my favorite lens and I do not even have one in my collection-thus no detailed repair notes.I can obtain them,but only the complete 'set'at a price!I have not found a free download of the later series of Canon repair microfiche,which contain the 200mm/f4. macro. |
pochini
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 14, 2005 - 01:52 am: |
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You're right, there's nothing other than the aperture levers on the mount side.
On the mount side there are the aperture levers, a couple of screws (one is glued) and, in the bottom, a small metal plate blocked with two glued screws. I could see only a small part of the bottom.
I'll not open the front side without detailed instructions because I don't know if I can remount it. It may require special tools and intruments to realign the lens that I don't have. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 14, 2005 - 09:05 am: |
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I have a lead on the required diagrams-keep fingers crossed.As this lens does not have a 'floating'element,I would think that careful disassembly with notes and marking reference points will suffice.The normal tools required for lens repair will be OK.I suspect that your biggest problem will be repacking the helicoid, in order to get the right feel over the whole travel.The official damping grease from Micro Tools seems to require a second mortgage to purchase! |
pochini
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 16, 2005 - 07:06 am: |
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Actually, I don't any lens tool at all...
The friction is OK and the focussing ring is very smooth. There is only some play in two different, probably unrelated, parts: the focussing ring moves up-down (from one side only, ie. it actually rotates), and the mount-side barrel is not tightly attached to the rest of the lens.
Looking into the front glass I can see the lens of the internal focus mechanism, which is not kept in place with another screwed ring, but I can't see is very clearly. Below, there are three glued screws (no idea if there is other glass in-between). So, I'm afraid that even if I can reach the bottom I cannot do anything to fix it, other than damaging the glass, which is perfect. I'll wait until I find the manual. |
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