Canon fd 50mm 1.8. Help me!

[Martin Singleton]

Got a bag full of Canon bits and pieces the other day with a couple of fd 50mm lenses, one is the newer f22 model which I've stripped down, defungussed and unstuck the aperture blades. The other one is the older breech lock mount. There is a small spot of fungus on the front element. I've started stripping down the lens but can't figure out how to separate the front elements. Are they cemented together or is there a trick to getting them apart? Any help is much appreciated. Thanks

 

[Mackinaw]

Looking at an optical diagram for the breechlock 50/1.8, from the front, the first element is free-standing, elements two and three are glued together. As for separating glued elements, I hear heat will help loosen the glue.

Jim B.

 

[David Lyga]

Some of the front element sets are heat sealed and that is something I despise about Canon. But on some of the Canon normals, the front element set has a plastic cap that can be snapped off to reveal the individual elements. On the heat sealed ones, I have not found a way to enter the seal in order to clean the inner sides of the front elements. - David Lyga

 

[AgX]

If cemented or even just heat sealed, how then could fungus reach or develop at these surfaces?

 

[Martin Singleton]

Thanks both. David, you're right, the newer one had the plastic cap - that was easy. The older one has a plastic surround and it looks like a melted/sealed coating. I think the seal must just be just dust proof rather than moisture proof. Ah well, I bought the bag for the AE1 Programme, the extra 50mm lens was a bonus, I was just going to hang onto it in case I found an older Canon body. The fungus is only a small spot at the edge of the front element, I'll put it on the window ledge and let the UV kill off the fungus and pop it in the spares box.

 

[David Lyga]

If cemented or even just heat sealed, how then could fungus reach or develop at these surfaces?

Oh, I assure you that it GETS there! To make something absolutely and completely moisture proof is far more difficult that you might imagine. Not being able to get at an element drives David Lyga absolutely crazy. These heat-sealed situations are a direct result of cost cutting, because threaded situations cost more. Canon was especially guilty of this. - David Lyga