Mir 1 infinity

Aanything · Expire: 2014-05-30

Today at a local photo fair I picked up some goodies: among these there's a beautiful shiny mir 1 2.8/37, for around 20 euros.
To my disappointment, it doesn't reach infinity for a little bit, even at f/8.
Before I proceed with removing the name plate, I'd like to know if anybody has already adjusted infinity on this lens and can give me a quick tip.
Thanks in advance.

sichko · Joined: 20 Jun 2008 Posts: 2528 Location: South West UK

I don't think that removing the name plate will help you.

The "optical unit" in this lens is easily removed from the "focussing unit" simply by unscrewing the two parts (there's a thread on the Forum somewhere describing how to do this). If you do that you will find that its position is determined by a metal collar or thick washer. It might be possible to reduce the thickness of this collar by 0.3 mm (the difference between M39 and M42 registers) so that, when you reassemble the lens, the optical unit will be 0.3 mm closer to the film/sensor plane. I haven't done this and it's some time since I had a copy of this lens in my hands. A possible problem might be interference between the front of the focussing ring and the back of the aperture ring as the lens is focussed towards infinity. You might get round that by removing some material from the front of the focussing ring - but some might consider that rather drastic.

Aanything · Expire: 2014-05-30

Thanks, I will look for the thread and give it a try.

Aanything · Expire: 2014-05-30

Ok, i managed to separate the two parts of the lens and got to the collar. I would like your (and/or anyone else's) opinion:
would you rather reduce the thickness of the collar, or sand an adapter that little bit that is needed to get to infinity?
The point is that this lens doesn't reach infinity as well on my m42 film cameras, so modifying the lens sounds reasonable, even though I usually prefer working on adapters (and I don't shoot film much often these days).

Thanks again.