Trying to unfungus a nice Canon FD 50mm 1.8

Jesito · Expire: 2015-01-07

Martinsmith99 has been so kind of providing me with one for free (thanks Martin!) and I committed to a tutorial on disassemby and fungus killing.

This first attempt has been unsuccessful (in removing the fungus) but anyway, I'll show the lens and the steps taken.

This is the lens. Martin told me about some incipient fungus around the top lens border:

You can see them quite clearly:

On the bottom lens there were also some suspicious spots:

So I started from the top. At first I thought the 50mm 1.8 had a screwed nameplate, so I took the rubber lens wrench for that diameter and tried to unscrew it:

But the plate was turning without unscrewing, so I went to the laptop and searched for "FD 50mm disassmbly" and found the page from Rick Oleson where he disassembles the 50mm 1.4. I learned there that the plate was glued and not screwed, so I protected the lens with s piece of microfiber fabric and placed a small plastic screwdriver under the plate. It popped up and showed the top of the lens itself:

Three small screws that fix the top. Taking them out , frees the retainer for the top optical element:

Gently turning down the lens dropped the top element.

It seems to be made up of two lenses, glued onto a plastic piece:

Not clear to me if the fungus was on top or inside the lens, so I used the common practice: hands cream on top of the lens:

For half an hour I was expecting the same results than with the 500mm mirror (that one had a worse infection).

But unexpectedly the treatment didn't provide any results. So I have to infer these fungus are not on top. It will be really difficult to disassemble the top element, so I assembled it back for now and see what else can be done.

Again thanks to Martin for such nice opportunity to learn about lenses..

Regards.
Jes.

wupdigoj · Joined: 18 Mar 2010 Posts: 85

Thanks for sharing. I am in the search for a 50 canon lens, and (as I always do) will look for a fungused or a not-working-iris one, for price sake. It seems a very easy lens to work with. Regards

Javier

Jesito · Expire: 2015-01-07

GT · Joined: 23 Nov 2011 Posts: 11 Location: Italy

Hi Jes,

the two lenses of the central element in 50 nFD 1.8 are not glued onto a plastic piece, they can be separated. I just did this by gently but firmly pulling the plastic piece (which allows rotation for focusing, by the way, so it couldn't be glued : ). Once you've done that, carefully pull the smaller lens, which will come out.
I'm presently cleaning my fungus this way : )

Ciao,
GT

Jesito · Expire: 2015-01-07

Pancolart · Expire: 2013-11-18

Sadly S.C. version has all front system elements wrapped in one piece of plastic which cannot be separated as described above. I already started carving plastic profile to release the front element (under which fungus resides). Is there a better way to get the element out?

kimherrick · Joined: 22 Nov 2015 Posts: 1 Location: florida

this is the "second" element from the front of a canon fd 50mm 1.8 lens. it is not a single element, it is either glued or welded together somehow. and this is where I have found fungus or iridescent snow flake-ish like patterns, which may be in the coatings. however this is not a single element as some have suggested, it is 2 elements bound together somehow. how do we get them apart?[ href=" target="_blank" rel="nofollow" class="postlink">

DigiChromeEd · Joined: 29 Dec 2009 Posts: 3460 Location: Northern Ireland

Gardener · Joined: 22 Sep 2013 Posts: 950 Location: USA

Malty · Joined: 30 Sep 2016 Posts: 1