Canon SERENAR 50mm F 1.9 disassembly

[OptiKen]

Happy Wednesday, APUG'rs!
I recently acquired a Canon collapsible 50mm F1.9 lens for my LTM cameras.
looking it over, I believe there is a small fungus growth fairly close to the center of the lens and I would like to be able to remove it and arrest the fungus before it grows.

Can someone point me to a web site or give me basic instructions on taking this lens apart to get to the glass?

Thanks in advance,

Ken

 

[gzinsel]

Can I talk you out of it?

 

[OptiKen]

Talk me out of the lens or talk me out of trying to take it apart?

 

[albada]

Unless you are experienced in repairing cameras, I strongly encourage you to *not* put a tool on that lens. I have repaired many cameras and a number of lenses over the past 20 or so years, and have acquired the necessary tools and skills for this kind of work. And I have an advantage over most folks: As a child, I repaired clocks and even watches for the fun of it. I collect cameras, and I can immediately tell when an inexperienced person attempted a repair, as it's almost impossible to avoid damaging the equipment if you're not experienced. So I strongly recommend that you either live with the fungus, or pay somebody to clean it.

That said, I note that most prime lenses consist of a front group and rear group, with the aperture between them. Often, but not always, one of these groups can simply be unscrewed by hand without employing a tool. Since your fungus is near the middle, you might try unscrewing either group, which would give you access to both inner surfaces, allowing you to clean them.

Mark Overton

 

[02Pilot]

All the statements above about knowing what you're doing and potentially damaging the lens apply. At the very least, get yourself the proper tools and work carefully.

That said, the body of the Canon 50/1.9 is pretty much a straight copy of the Leitz Summitar with a couple of minor differences, while the optics are very close to the earlier Summar. Opening up the lens is done just like with the Summitar, which is not terribly difficult and can be seen here: http://justinlow.com/articles/repair-leica-summitar

Fungus is best cleaned with moisturizing hand cream applied generously for five minutes, removed, and the glass then cleaned normally.

I will say that I really enjoy that lens. At wide apertures it gives a really distinctive look, with lots of softness around a relatively sharp center and sometimes swirly out-of-focus areas, while stopped down it's quite sharp. Very flexible.

 

[OptiKen]

Thank you. This information will be very helpful.
I have repaired a few cameras (destroyed a couple as well) and repaired or cleaned many lenses but have never taken apart a collapsible lens which is why I requested information from someone who has already taken one apart. I like to avoid 'trial and error' as much as possible because too often 'error' can follow 'trial'.
RE: Albada I've also repaired a few clocks (never watches, however) and think that is what attracts me to the old cameras. They are, afterall, mechanical marvels just like clocks and I find them fascinating.

Thanks again

 

[blee1996]

Thanks for the information here, I managed to clean a new-to-me collapsible Serenar.

Here is another CLA guide with tons of photos:

Canon Serenar 50mm f/1.9 Lens Clean, Lubricate, Adjust (CLA)

Here’s a rather thorough walk-through of the disassembly, cleaning, and reassembly of a circa 1950 Canon Serenar 50mm f/1.9 lens. You can read about its history in another post. Please read m…

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