Canon LTM Canon L1 & 35mm f1.8

Canon M39 M39 screw mount bodies/lenses

lawrence

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Hi Fellow Canonophiles!

A couple of questions:

1. Is it possible to easily adjust the vertical alignment of the L1 rangefinder?

2. My mint-ish 35mm f1.8 has a loose aperture ring. Is it a good idea to tighten it and, if so, how?

Regards

Lawrence
 
lawrence said:
Hi Fellow Canonophiles!

A couple of questions:

1. Is it possible to easily adjust the vertical alignment of the L1 rangefinder?

Yes, it's easy on all the "round-window" Canons (previous to 7.)

  • Remove knurled trim ring around the circular RF window.
  • Under the trim ring, you'll see that the RF "lens" is mounted in a round black ring with two slots in it. The "lens" is actually a shallow prism that adjust the vertical RF image when you rotate it via these slots.
  • Find a tool that will grasp the slots firmly without damage. I use a pair of square-tipped tweezers that I have filed so they fit the slots exactly.
  • When you rotate the RF prism, the RF image will move in a circle. Rotate it a bit and see if the vertical alignment is getting better or worse.
  • Keep rotating until you "sneak up" on perfect vertical alignment.
  • Adjusting the vertical alignment disturbs the horizontal alignment (the prism moves the image both vertically and horizontally) so now you have to reset the horizontal position at infinity.
  • As you probably know, the horizontal adjustment is a tiny screw under the chrome cover screw at the corner of the VF window. Turn it until a distant object lines up correctly at infinity.
  • You're done!

I don't know about the aperture-ring problem, sorry.
 
A loose aperture ring isn't any problem, per-se. On this lens, it isn't a structural part of the iris, it's just a mechanical linkage to the real guts.

However, is it really the aperture ring that's loose, or the whole barrel of the lens? Most of the Canon 50mm and wider lenses are a lens barrel that is inserted into the focusing mount, and held on from the back with a threaded ring. If that ring were loose, not only the aperture ring would be loose, so would the front ring, and the entire optical block of the lens. (The aperture ring is rearmost exposed part of the lens mount.)

The ring isn't hard to tighten with a spanner wrench. But some incompetent person may have previously dissasembled the lens, and left out the shim that sets infinity focus correctly. Do check that the lens is focusing accurately.

Hmm. If you focus this lens to 1 meter, the lock ring winds up sticking out the back of the lens. You could put a metal ruler in the two slots and tighten it, if it needs it. So you wouldn't even need a lens spanner.
 
John: You are correct about the threaded ring on the 35mm f1.8. It had worked loose so I have tightened it and now the lens is like new. Many thanks for this suggestion.

JLW: Many thanks for your suggestion also, however I've decided to leave things as they are for the moment because the camera is focussing perfectly and I'm a bit afraid of upsetting things.
 
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