Canon FD 50mm 1.8 Breech-Lock Help

Got this lens at a local fleamarket for 5$.

 

It is mechanically sound but dirty as sin. There was a little critter between the 2 rear element groups long dead moving around as the lens changed position. My experience with this lens is modest and I managed to address the rear part of the lens with a bit of trial and error. (The critter and its loose bits were given a proper burial in the trash bin).

The front group however, has got me stomped. Tried to remove beauty ring with friction tool, but all it does is spin in place.

There is haze from condensation within the elements so I am trying to address it.

 

Any tips would be greatly appreciated.

 

I know that feeling.. you know what's wrong, but you can't get started. HAve you tried the lens? MAybe the "problems" are no sitrusive and do not affect the image quality?

If it's a plastic nameplate ring, your friction tool may be pressing it downwards so that the grooves of the thread might not be engaging properly and slipping. It should come out if you can turn it without downward pressure. If all else fails I have sometimes drilled two small holes opposite each other, when this should be possible.

 

There's a very good write up about opening up a similar lens on Rick Oleson's site:

 

LINK .......... Canon FD Lens Service

I know that feeling.. you know what's wrong, but you can't get started. HAve you tried the lens? MAybe the "problems" are no sitrusive and do not affect the image quality?

Chuck - you are absolutely right on that as image impact would be minimal if any in 35mm photography, it’s more of a thought of leaving it like that that bothers me :)

If it's a plastic nameplate ring, your friction tool may be pressing it downwards so that the grooves of the thread might not be engaging properly and slipping. It should come out if you can turn it without downward pressure. If all else fails I have sometimes drilled two small holes opposite each other, when this should be possible.

 

There's a very good write up about opening up a similar lens on Rick Oleson's site:

 

LINK .......... Canon FD Lens Service

John - had similar thoughts and many thanks for pointing that out. This ring is indeed plastic, seems canon started cutting corners with this model, while preserving quality of optics. When I removed rear mounting ring and plate, I was surprised to see that the entire rear group was held in place under pressure with a rubberized plastic sleeve, instead of the threaded retaining rings.

The beauty ring on your lens is glued on with contact cement. You can pry it off by slipping something under the inside or outside with a thin, flat, flexible piece of plastic or a feeler gauge. Alternatively, you could try using sticky pieces of tape and try to pull it out. The bayonet mount for the lens hood and front lens group are each held in place with three screws, the removal of which will give you access to the diaphragm and the front of the rear lens group. There are several versions of the FD 50mm f/1.8 S.C. lens. Canon continuously made changes to this lens to reduce its size, weight, complexity and cost. On earlier versions, the diaphragm is a six blade modular unit that can be easly removed and cleaned. On newer versions like yours, it's a five blade non-modular unit. Be forewarned, if you remove it for cleaning, you'll have to reassemble it blade-by-blade.

The beauty ring on your lens is glued on with contact cement. You can pry it off by slipping something under the inside or outside with a thin, flat, flexible piece of plastic or a feeler gauge. Alternatively, you could try using sticky pieces of tape and try to pull it out. The bayonet mount for the lens hood and front lens group are each held in place with three screws, the removal of which will give you access to the diaphragm and the front of the rear lens group. There are several versions of the FD 50mm f/1.8 S.C. lens. Canon continuously made changes to this lens to reduce its size, weight, complexity and cost. On earlier versions, the diaphragm is a six blade modular unit that can be easly removed and cleaned. On newer versions like yours, it's a five blade non-modular unit. Be forewarned, if you remove it for cleaning, you'll have to reassemble it blade-by-blade.

Thanks Gordon, blades are actuating fine so do not intend to mess with them. I will try my heat gun to see if I can dislodge the beauty ring

Looks like Gordon was right, a lightly cemented beauty ring easily pried after some heat

 

Well just done, as good as it is going to get :), front group completely cemented in a plastic holder. Cleaned exposed surfaces best i could. This has got to be the cheapest lens Canon made during this time. Had to apply nail polish on screws to make sure they stay in place. Should be a decent shooter and my T90s seem to like it.