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Canonfdenthusiast
Tinkerer
Username: Canonfdenthusiast
Post Number: 1
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 08, 2011 - 03:18 pm: | 
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Hello
I am hoping someone can help me with how to access the lens elements in the zoom/focusing assembly of this beautiful old canon FD 80-200 f4 L lens as it has developed signs of fungus and needs a clean.
The fungus is on the fourth(?) lens element counting from the front of the lens, i.e. the front-facing lens element of the focus/zooming group. I've tried reaching the affected element both from the front and rear, but alas no luck.
When I removed the front group (two lenses), I was faced with a big flat lens element that did not seem possible to remove from this side (e.g. signs of threads). Unfortunately this element sits between me and the area with fungus. If anyone could shed any light on how I could remove this one I would be very grateful.
Opening it from the back, removing the rear group and the aperture assembly, I can clearly see the lenses involved in the zoom/focusing action, but I cannot see any way of dismantling them or taking them out to reach the affected element.
If anyone has experience with servicing this lens or similar lenses, any hints, guidance or instructions would be very gratefully received.
Many Thanks.
CANON FD Enthusiast |
Christof
Tinkerer
Username: Christof
Post Number: 1
Registered: 07-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, July 18, 2012 - 06:15 pm: |
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Since I had exactly the same problem, I will post my experience even though this thread has been started quite a while ago.
The trick to access the inner elements is below the rubber grip area of the lens. You have to remove the rubber band (I kind of wrapped it over to do that). Then you will find a transparent plastic foil fixed with Scotch tape. Remove it, then you have access to a couple screws. You only need to remove the screws that run in two slits guiding the zoom and focussing movement. Once those two screws are removed, you can simply rotate the front part of the lens, it will unscrew and separate from the rest of the lens: Voilą! That's it. For me it was giving me access to exactly the surface I needed to clean.
Reassembling is quite easy, just take care that you screw in the front part of the lens the same way you took it out, best is to mark it when disassembling. OK, putting back the rubber band is not exactly easy, but you will make it.
Good luck!
Christof |
Leesobing
Tinkerer
Username: Leesobing
Post Number: 74
Registered: 01-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 19, 2012 - 12:16 am: |
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http://ferling.net/Sears80-200f4.htm
like this? |
Glenn
Tinkerer
Username: Glenn
Post Number: 1035
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 19, 2012 - 10:18 am: |
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Rubber grip is easily removed by working 3 or 4 pieces of thin but rigid plastic strip equally spaced under the grip, then slide the grip out of the groove and onto the plastic strips. The same can be done by easing a thin plastic spatula under the grip and as one works the spatula around the barrel, just push the grip out of the retaining groove and onto the outer surface of the barrel. |
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