Modified lenses?

[tthue]

I look for screw lenses for collection and use (M8). I can see from pictures (on eBay, se picture attached) that some lenses have a screw rear part mounted, like a separate adapter.
I have search for information on how rear parts are designed, but found nothing.
Now I ask the RF forum for help:
How is the rear part of Leica screw lenses designed and mounted?
Is the lense (picture) a genuin lense, or a modified one?
Thanks, Trond

 

[laptoprob]

Welcome to the forum, Trond. You are probably looking for a screw-to-M bayonet adapter. Then you can use your screw mount lenses on the M-series cameras.
These adapters exist for various lenses, they bring the correct framelines in the finder.

 

[Dralowid]

Hi Trond,The lens in your picture looks odd. I can see that is 135mm(?) and the red dot on the side shows that it was originally designed to be an M lens.

BUT a screw mount has been crudely attached to the back. It does not look like a factory modification. I'm really not sure that this would be a good choice of lens. Particularly because depth of field on a long lens like this is limited.

Screw mount lenses do not have red dots and the lens mount is much more 'integral'. For your M8 it is easy to find the adaptors mentioned by Laptoprob that will convert screw to M.

Be careful...

Michael

 

[tthue]

Thanks Michael.
I like your comments.
NB. It is a 90mm Summicron F2.
I have looked into 2-3 of these lenses. They have all different rear parts.
I try to find ok technical info on the net, but nothing.
Regards, Trond

 

[mike goldberg]

Like Rob said above, you need a screwmount to M adapter. It pays to get a good one like Voigtlander or Bower, whose thickness is no more than 1.1mm.

 

[Roger Hicks]

The original 90/2 could be detached from its focusing mount for use on a Visoflex. God knows what is on the back of the one you posted. Really, I'd be VERY hesitant to buy privately on line until you know a lot more about Leica mounts: buy from a dealer instead.

A while back I tried 24 different lenses, 1936-2006, on my M8 and had lots of fun: the article appeared in Shutterbug magazine. Unfortunately I now REALLY want a Thambar...

Cheers,

Roger