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Canon FD 55 1.1.2 S.S.C. fungus
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PostPosted: Wed Jul 29, 2020 4:24 pm    Post subject: Canon FD 55 1.1.2 S.S.C. fungus Reply with quote

Hi,

I have a Canon FD 55 1.1.2 S.S.C. with a fungus on the rear element.

I took it to a repair shop but they said the glasses where the fungus is located are glued together.
However, I don't trust them so I'm not sure if they are right (There aren't good repair shops in my city).

Does anyone know if they are right and in that case what could I do?






PostPosted: Wed Jul 29, 2020 9:08 pm    Post subject: Re: Canon FD 55 1.1.2 S.S.C. fungus Reply with quote

alo91 wrote:
Hi,

I have a Canon FD 55 1.1.2 S.S.C. with a fungus on the rear element.

I took it to a repair shop but they said the glasses where the fungus is located are glued together.
However, I don't trust them so I'm not sure if they are right (There aren't good repair shops in my city).

Does anyone know if they are right and in that case what could I do?

I don't think this is the case.

For fungus to get into doublet, I would expect some separation to occur first.
There might be one going on (separation can be extremely hard to see), but somehow I doubt it.
At the first glance this looks like pretty usual mild fungus.

I'd wager they just don't want to touch it, since it's a big time investment and thus not very profitable.


PostPosted: Wed Jul 29, 2020 10:21 pm    Post subject: Reply with quote

I thought the same because I suggested to them that I was scared about a fungus into doublet. However, is there a way to be sure if there is a doublet in this lens? I’m not able to find a scheme online


PostPosted: Wed Jul 29, 2020 11:13 pm    Post subject: Reply with quote

alo91 wrote:
I thought the same because I suggested to them that I was scared about a fungus into doublet. However, is there a way to be sure if there is a doublet in this lens? I’m not able to find a scheme online


https://en.wikipedia.org/wiki/Canon_FD_55mm_f/1.2_AL


PostPosted: Thu Jul 30, 2020 3:35 am    Post subject: Reply with quote

visualopsins wrote:
https://en.wikipedia.org/wiki/Canon_FD_55mm_f/1.2_AL


Mine is the S.S.C. version (without any Al or L or aspherical) and I’m not able to find the right scheme.


PostPosted: Thu Jul 30, 2020 10:10 am    Post subject: Reply with quote

alo91 wrote:
However, is there a way to be sure if there is a doublet in this lens?

I've never seen a 7 element lens without at least one of those.
Again, I would just ignore the shop response and forget about the doublets.

But if you insist, it's listed as 7/5 on Canon official website, so there are two doublets inside:
https://web.archive.org/web/20150921153232/http://www.canon.com/camera-museum/lens/fd/data/50-85/fd_55_12.html


PostPosted: Thu Jul 30, 2020 12:26 pm    Post subject: Reply with quote

It's not in the doublet. I concur with the opinion that they decided it's a PITA and they just did not want to deal with it.

PS. See that iridescent ring in the middle of the lens? That's the rear doublet.


PostPosted: Thu Jul 30, 2020 7:09 pm    Post subject: Reply with quote

I think I founded the optical scheme and I really think that you were right to say that the fungus isn’t in the doublet.
The problem now is that in the past I have already token this lens to another store and they wasn’t able to remove that fungus.

What could be the problem? Maybe it’s not easy to remove the rear glass?


PostPosted: Fri Jul 31, 2020 5:48 pm    Post subject: Reply with quote

alo91 wrote:
What could be the problem? Maybe it’s not easy to remove the rear glass?

From the looks of it, the rear element is glued into a metal sleeve which is screwed into the rear group assembly. Your second photo appears to show just where the connection point is. To me it looks separable, but it requires tools and the ability to get purchase to apply torque. It also depends on how well it is threadlocked.


PostPosted: Sun Aug 02, 2020 1:59 pm    Post subject: Reply with quote

I doesn't look too bad. Out of curiosity, what's your interest in cleaning it? I totally understand if it's just the peace of mind that the lens is completely clean throughout. I'm potentially looking at the same issue with one of my optics. But pragmatically speaking, I don't imagine this is affecting image quality too much, if at all. Just curious!


PostPosted: Thu Aug 06, 2020 3:01 pm    Post subject: Reply with quote

justtorchit wrote:
I doesn't look too bad. Out of curiosity, what's your interest in cleaning it? I totally understand if it's just the peace of mind that the lens is completely clean throughout. I'm potentially looking at the same issue with one of my optics. But pragmatically speaking, I don't imagine this is affecting image quality too much, if at all. Just curious!


Certainly, one of my motivations is to have perfectly clean lenses but I'm also worried that the fungus might get worse. I'm sure, although I've used it a lot, it's suddenly gotten worse.