Fungus in Canonet lens

srs5694 · Aug 25, 2005

Yesterday I received a Canonet GIII QL17 that I bought off of eBay. It was advertised as being "as is" from somebody who claimed to not know much about cameras, so I knew it was a bit of a gamble. Anyhow, the camera's mechanically sound, with good metering, shutter action, and film advance. The trouble is that the lens has some fungus. I'm wondering what would be involved in tearing down the lens to clean this out. If it's do-able, I might just treat this as a learning task (I've never done this sort of thing before). If it's likely to be too much of a pain, I'll sell the camera on eBay for parts. Any advice or pointers to Web sites with instructions on how to take apart the lens on one of these cameras? Thanks.

roteague · Aug 25, 2005

Go out and take pictures with it. You probably won't even notice the fungus; a couple of my LF lenses have fungus, and I have no problems with them.

gnashings · Aug 26, 2005

How much do you want for it?

I have taken a simpler lens apart on another RF (Canter Beauty) - and it was pretty straight forward as long as you had the right tools (I didn't...). I would try the quality of the pics before tearing into it. Also, I have heard of ways to "kill" the fungus without tearing into the lens - but I have never tried it or have any info that I would consider reliable enough to pass on as fact. Perhaps others have heard of such methods?

Max Power · Aug 26, 2005

Seeing that it's a metal leaf shutter, couldn't you set the camera out in the sunshine for a couple of hours?
For some reason I think that I've read somewhere that this does the trick. Otherwise, as Peter says, take it apart. It's fairly easy and if you do a Google search for 'classic camera repair' you'll find a web-page and a repair forum which describes some of the tools needed and even shows how to pull the elements apart.

Hope that this helps,
Kent

John Koehrer · Aug 26, 2005

srs5694,
It's not a difficult task at all. You will need a spanner of some sort. If you have a pair of needlenose pliers to sacrifice the tips can be ground down to fit.
If you take a look at the lens, there are two notches inside the decorator ring. You need to be able to insert the spanner into those notches to unscrew the front element. They are aluminum so you need a good fit.
Personally I also remove the decorator ring which is the ring with "canon lens etc." molded in it. Beneath the decorator ring is a plate that has various size holes in it to adjust the ISO. This will just lift out. When you reassemble the lens there's a post that engages this plate to change ISO, can't miss it.
Set shutter on Bulb, Clean lenses with Alcohol or ammonia & reassemble.
It's really pretty easy, as they say "it ain't rocket science"

gnashings · Aug 26, 2005

Max Power said:
Seeing that it's a metal leaf shutter, couldn't you set the camera out in the sunshine for a couple of hours?....

That was one of them - I also heard of people using tanning lamps - apparently it does work, and its "non-invasive", but I cannot sell this method as anything other than hearsay, having never tried it me self!

You may get the idea that I am some kind of QL17 addict or something... and I just want to put an end to those rumours...uhm... yes...

Best of luck - do fix it, its an amazing little rf!

Peter.

srs5694 · Aug 27, 2005

Thanks for the advice. I'll look into disassembling the lens and cleaning the affected elements. The fungus isn't bad enough that it's caused obvious degradation in image quality (I did run a roll through the camera, and the photos seem fine), but I definitely want to be sure to kill it and prevent it from spreading.

Trivette · Aug 27, 2005

It's the UV in sunlight (and tanning lamps) that kills fungus. So exposing the lens to a black (UV) light will kill the fungus. It shouldn't do any harm to a metal shutter. However, I don't know how long it would take.

gnashings · Aug 27, 2005

Trivette - I suspected that - thanks for confirming. I would say, leave it on a window sill for few days with no lens cap - should do the trick?

srs5694 · Aug 28, 2005

FWIW, I'd done some reading on lens fungus several months ago because I had an old SLR lens that was infested. (It wasn't a very good lens to begin with, so it wasn't much of a loss.) One of the best URLs was http://www.chem.helsinki.fi/~toomas/photo/fungus/, which has pictures and quotes from various people on how to deal with it (from Usenet or forum posts, I'd assume). The UV light suggestion has both proponents and detractors on that page. At best, it'll arrest the growth of the fungus -- which would probably be enough for my Canonet, since the fungus hasn't yet seriously damaged the lens. At worst, UV light exposure will have no effect. I've also heard (here, among other places) that cold cream (the skin care product) will kill lens fungus and remove it, but of course you've got to disassemble the lens if the fungus is on any interior elements. Hence my desire for Canonet lens disassembly advice. Even cold cream won't help if the fungus has already damaged the lens coatings, which is likely for most fungal infections.

I plan to buy some cold cream and try my hand at disassembling the lens to clean out the fungus. If I manage to ruin the camera (maybe a 1 in 3 chance, at a guess, given my level of experience with camera repair), then I'll treat it as a learning experience and get another one. Canonets aren't exactly rare on eBay.

Jon Shiu · Aug 28, 2005

If you want one to practice on, or for lens elements, let me know. I have one with excellent lens, but broken shutter. You can have it for the cost of postage.

Jon

gnashings · Aug 28, 2005

As a big fan of that little camera, I wold love to see a blow-by-blow account of your adventures with cleaning it (maybe pictures?)... Mine may need it some day

John Koehrer · Aug 28, 2005

srs5694,
I don't think I'd recommend putting cold cream on the lens elements unless you want to risk getting it into the shutter itself. There's not a lot of clearance in the mechanism you're working on & The springs in the shutter aren't that powerful. It takes very little in the way of surface tension to bind up the shutter, that's why oil on the shutter blades freezes the shutter up. Again, alcohol or ammonia applied with a Q-tip dampened with the appropriate cleaner will do the job.

Captain Slack · Aug 29, 2005

gnashings said:
Trivette - I suspected that - thanks for confirming. I would say, leave it on a window sill for few days with no lens cap - should do the trick?

Probably not. Glass windows block most UV light. If you're going to leave it on a window sill, I'd make sure to open up the window.

Trivette · Aug 29, 2005

Captain Slack said:
Probably not. Glass windows block most UV light. If you're going to leave it on a window sill, I'd make sure to open up the window.

Also, camera lenses themselves (and their coatings) block most UV light. It might take two or three weeks of outdoor exposure to sunlight to kill all the fungus.

Fungus in Canonet lens

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