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Dcshooter
Tinkerer
Username: Dcshooter
Post Number: 7
Registered: 09-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 18, 2013 - 01:32 pm: | 
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Hi everyone,
I just picked up this lens today as part of a bulk lot, and it's in nice shape except for the fact that the front barrel is somewhat loose. I figured, I'd just take the name ring off, and there would be some screws underneath for me to tighten. After spending half an hour getting the ring off (it was slightly dented and therefore cross threaded - ugh!), I discovered there were no such screws.
Figuring there would probably instead be some grub screws under the grip, I removed it, only to find no such screws there either. The focus ring, however, seems to be a two-piece design, indicating it should separate somehow. Unfortunately, I can't for the life of me figure out how to do it.
There appear to be some possible traces of tape; I am wondering if the ring halves were originally taped together and some chucklehead who repaired it in the past simply super-glued them together. Repeated applications of MEK don't seem to be working, so I figured I'd throw it out there to the experts.
Is there something I am missing? Is this only disassemblable from the rear? I took the mount off, and attacking it form there doesn't look like it would be a trivial task.
Links to service manuals, etc. would also be greatly appreciated.
Thanks! |
Arfd
Tinkerer
Username: Arfd
Post Number: 15
Registered: 01-2013
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 18, 2013 - 04:55 pm: |
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The problem you describe is the same as I encountered with the Mk1 version (f16) of this lens. I'm not 100% certain but the name ring secures the filter ring. Just tighten it with a rubber tool. However, be careful that when unscrewing the name ring you didn't also partially unscrew the front optical cell!
Looking at the factory issued schematic, the part which appears to be the filter ring and which they call the 'front tube', is secured on the outside by 3 recessed screws, but I couldn't find them. Also there are no screws under the rubber focusing grip.
The lens is perhaps more complicated than first appearances as focusing seems to be achieved by moving the rear cell with respect to the front group.
There shouldn't be any reason to remove the mount as it can be a bit tricky to get the aperture setting ring back on. |
Dcshooter
Tinkerer
Username: Dcshooter
Post Number: 8
Registered: 09-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 19, 2013 - 05:23 am: |
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Hmmm. Mine is the MK1 as well. I have tigntened the name ring down as far is it will go, but there is still some play in the front barrel/filter ring, causing rubbing against the focus ring when focusing. And like you, I don't see any screws visible after removing the name ring.
Do you happen to recall how the 2 halves of the focus ring were attached to each other? As stated, it appears there might have been tape once. Do you remember if yours was taped, or am I simply seeing the adhesive residue from the rubber grip?
The other option is to try to remove the entire front group, but my spanners aren't narrow enough to grab the notches on either side of it given the lack of space between them and the sides of the barrel.
Thanks! |
Arfd
Tinkerer
Username: Arfd
Post Number: 17
Registered: 01-2013
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 19, 2013 - 08:53 am: |
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My version of this lens was made at the end of 1980. I don't recall the focus ring being in 2 halves or any evidence of tape, but I didn't remove the focus ring from the body, just pulled back the rubber grip to see if any screws or access holes were present. (The 50/1.4 has access holes under the rubber grip)
PS Trying to make sense of the schematic. It appears the focus ring is indeed in 2 parts, the front part screws into the numbered distance ring. If the front part is unscrewed and lifted off the 3 edge screws holding the filter ring should be visible. |
Dcshooter
Tinkerer
Username: Dcshooter
Post Number: 9
Registered: 09-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 20, 2013 - 03:05 pm: |
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Got it! the rings were stuck together, but eventually I got them apart. The screws holding the front barrel were loose, and tightening them up did the job.
Thanks for your help! |
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