Canon 28mm f3.5 fungus

[ALFA MALE]

G'day,

I recently acquired a cheap canon 28mm f3.5 with the intention of trying out the focal length. It was cheap because it has some fungus. I really like using the lens I was thinking of having a crack at removing the fungus. I'm a complete newbie to DIY lens repairs but quite comfortable taking things apart and putting them back together. I've bought a lens wrench, but I'm not sure where to start on the lens. There seems to be two rings in the back with notches and a bunch of screws, what do each of them hold in place? Where should I start?

The other issue with the lens is the focus ring often unscrews, if anyone has any tips on how to tighten that up properly while I'm working on it, that would also be really helpful!

Many thanks,

Lloyd

 

[Mackinaw]

Is the fungus located in the front group (in front of the aperture) or in the rear group? Canon rangefinder lenses are constructed "logically" and are easy to take apart and reassemble. Normally, all you have to do is to use a lens spanner to remove retaining ring(s) which allows a lens element to be removed. I've cleaned several without any help from a repair manual. Just took it apart, cleaned, and reassembled. Good luck.

Jim B.

 

[ALFA MALE]

Is the fungus located in the front group (in front of the aperture) or in the rear group? Canon rangefinder lenses are constructed "logically" and are easy to take apart and reassemble. Normally, all you have to do is to use a lens spanner to remove retaining ring(s) which allows a lens element to be removed. I've cleaned several without any help from a repair manual. Just took it apart, cleaned, and reassembled. Good luck.

Jim B.

Hi Jim, sorry I thought I'd added an image to the original post which was to much of the explaining. The image is there now, and as you can see the fungus is in the rear. The image also shows where the retaining rings are. Do you know which of the rings I should remove first? I'm trying to avoid taking apart anything which doesn't have to be.

Lloyd

 

[Mackinaw]

Forget about the screws. I'd remove the outer retaining ring first, then try and remove either an assembly, or an element. Next step would be to remove the inner ring.

Take it slow and don't be afraid that you're going to mess up. You're not. These lenses come down an assembly line and were designed to be easily assembled. As mentioned in my first post, assembly and disassembly is very "logical". Once an element or group is removed, it will make a lot more sense to you.

Jim B.

 

[charjohncarter]

This looks very similar to my 35mm Serenar F3.5.

Face up remove the front element and clean the removed element, then clean the front of the next element. Replace the front element.

Turn the lens over and have the f stop at maximum aperture.

Now remove the retaining ring. The remove the next element and clean. Clean the rear of the middle element without removing.

Do not lift the lens after you have turned it over. This will cause the parts to move and open, then you have fiddle to get them together.

This is a quick clean but I do it every time I use my lens because it tends to haze.