Canon LTM My 1st LTM-mount Canon Rangefinder

Canon M39 M39 screw mount bodies/lenses
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popitz

The Rangefinder Junkie
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Jun 28, 2005
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I just got a user Canon P with a 50/1.8 lens. And I blame it on Joe and his P's :).

Got it quite cheap compared to what I usually see on eb*y. The first curtain is crinkled just a little bit but the second curtain is perfectly fine. The viewfinder and RF patch is still clear. Everything seems to work fine.

The lens however, has some fungus inside :(. Is there anything I should take care of when dismantling it for cleaning?

I haven't checked it out thoroughly so if there are some things I should be aware of, I'd appreciate any info. Thanks.
 
please allow me to take full responsibility!
and if you ever need a camera sitter, i am available.

we will need a more techie member to help with the fungus question.
enjoy the camera!
joe
 
Hi,
As another "new" Canon owner, let me try to help. I can't offer specific advice on the Canon lens yet but I have serviced a number of FSU lenses. First of all, how bad is the fungus and whereabouts in the lens is it? You may get away with just removing the relevent group rather than going deeper.

Kim
 
popitz said:
The lens however, has some fungus inside :(. Is there anything I should take care of when dismantling it for cleaning?
Click to expand...

1) Consider leaving it alone. Try shooting with it, see how bad it is first.

2) Don't store it with your other lenses. Yes, lenses can share fungus.

3) Sometimes bright light through a window will kill off and render somewhat transparent a case of fungus - not so much in my experience, but worth a shot.

4) The back of the lens is generally coated with a much softer coating, the inside of lenses sometimes even more so. Even very delicate cleaning can leave permanent scratches that will affect your photos more than the fungus, so be careful when gouging around in there with a q-tip.

5) If you take out more than one lens element, make a drawing of the lenses and their arrangement (like which direction they curve in) when you take them out. Quite often, they'll go back together the wrong way without a complaint. And since they are not SLR lenses, you won't know it until you see your prints and begin to curse loudly.

6) Anything that is screwed in should be screwed back in to the same depth. Make a drawing of the alignment of the rings by their slots.

7) Consider getting or making a spanner wrench. Consider it an investment, you'll be doing this again. Like cameras, you can never have too many tools.

http://www.micro-tools.com/Merchant2/spanner.htm

http://www.micro-tools.com/Merchant2/lens.htm

8) Remember that fungus lives by eating things, like everything does. And sadly, the fungus that inhabits lenses often excretes a type of mild acid. You can remove the fungus and discover that the coating underneath has been eaten away. This may or may not affect your photos in any observable way.

All dirt, scratches, coating loss, and other defects in a lens affect the images it makes. The question is always 'how much' will it be affected, and how will it be manifested? It can be as simple as a general loss of contrast, hardly something you even notice, or a tendency to have increased flare problems, or it can be huge nasty chunks of ugliness in the negative, destroying it's use as a photograph. Only you can tell what is acceptable and what is not. I've seen some photos on pnet taken with a lens you'd think had been dug out of a pile of horse manure, and the resulting photos looked fine to me. Truly amazing when I think how much I obsess over clean optics.

Best Regards,

Bill Mattocks
 
Some fungus, any fungus growth needs to be properly cleaned. That is nice RF camera, by the way and yes Joe is on to something.
 
Solinar said:
Some fungus, any fungus growth needs to be properly cleaned. That is nice RF camera, by the way and yes Joe is on to something.
Click to expand...

I disagree. If a thorough examination shows that a) the fungus is already dead or b) the fungus has already done terminal damage to the lens, the there is little to be gained by cleaning it, and much to be lost if the lens can still be used in some capacity.

I don't propose that a recent or new fungus growth should be ignored, of course.

Best Regards,

Bill Mattocks
 
How can you tell if fungus is dead or alive?

This isn't he beginning of a bad joke, I was just wondering.
 
Call it "bokeh " and leave it as-is. That will give you an excuse to buy a crisp 35. Leading to a crisp 50. and a crisp 100. And a 25. And another P.

Etc.
 
Wow, thanks for all the quick responses.

Anyway, while you were all busy typing those very helpful information, I just went ahead and disassembled the lens (I just can't help keep my tinkering hands away from it :)). Disassembly was quite straightforward just as John mentioned. The fungus (or what seemed like fungus to me) was in the innermost element. I gave it a light wipe with a piece of microfiber cloth and it came off cleanly. Just like that. The lens is now very clear except for a very small scratch in the rear element (it was already there when I got it).

Can't wait to run a test roll. Unfortunately, we're going to have a rainy weekend :(.

Thanks again to you all.
 
I have also had several lenses where the Fungus cleaned right-off and did not leave any marks in the coating. Maybe it was still alive? So I guess the only good fungus is no fungus, but dead fungus is the worst of all.
 
FrankS said:
How can you tell if fungus is dead or alive?

This isn't he beginning of a bad joke, I was just wondering.
Click to expand...

If it posts on RFF...ok, just making a bad joke.

Perhaps I should have said 'active' or 'inactive'. I've got a few old lenses that have fungus. They had it when I got 'em, and they've got it now. It does not seem to be spreading. I'd call that inactive. I have another lens, which I just recently sent to a fellow RFF'er to borrow for awhile, that has fungus that just 'appeared' sometime since I last used it. I figured that was 'active' and I took out the back element and cleaned the fungus out.

I guess the point is that sometimes the cure is worse than the disease. If an inactive fungus has eaten into the lens coating, the cleaned result could be worse than the damage that existed before. Is an occlusion worse than a diffraction? I guess there's no telling until you clean it, and then of course, it's too late.

Best Regards,

Bill Mattocks
 
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