LTM lens changing

[ktran]

Hi all,

I'm reading conflicting info on this subject. So, should I be setting a lens to infinity before screwing it on, or setting it to its shortest focal distance, or does it really not matter? I know, for instance, that my Jupiter-8 doesn't really find the thread very well if I try to mount it when it's set to its shortest focal distance, but my Summitar and 9cm Elmar don't seem to care.

Does the round Leica RF cam vs. the flat soviet RF cam have anything to do with this? Once and for all, how the heck should I be screwing the lenses in??


thanks!

 

[Vickko]

Shouldn't matter.

 

[fuji645]

It doesn't matter. I've had a IIIc and a Canon, with numerous screw mount lenses--Nikor, Leitz, Angeniux and Canon. The most important thing to be concerned about is that when you thread the lens to the body, be very careful so that you don't strip the threads on either camera or lens. I've never had a re-engineered FSU lens for my Leica's so maybe that's an issue that is relevant to that particular genre. On my Kiev one has to set the lens at infinity prior to mounting--whether the interior or exterior mount--or else it will not sit correctly on the camera body.

 

[ktran]

Thanks guys. I guess it's just the Jupiter that's a bit weird.

 

[pbo]

I sometimes find mounting lenses set to min focus distance easier (on Bessa-R), maybe because that way rangefinder coupler of the lens is all the way inside the lens.

 

[Wlodek]

Safer with lens set to min. distance. Especially with odd brand lenses.

 

[rover]

I find gently turning the lens backwards until I feel a little jump, the thread of the lens slipping over the start of the thread on the body, helps line the lens up. Once I feel that I gently start turning it on.

Lots of times this works. Some times it doesn't. Maybe I just do this to feel like I know a secret, but hey, I am going with it.

 

[former member]

Best to set to minimum distance:
1) less push from the RF Cam follower as you screw in;
2) Lenses with "tongue" type Cams would cause RF cam follower to go back and forth as the lens screws in;
3) FSU collapsible lenses have slightly longer levers that hit the slow-speed dial on Japanese and German cameras with separate dials.

 

[ray*j*gun]

Be careful using any Asian lens (mine was a canon 135) on FSU's. Be sure the lens focus cam is round not contoured. I had said Canon get stuck on a Fed 2 due to the Fed's non round focus cam. Fortunately the Fed back could be removed and I was able to hold the camera cam while unscrewing the lens.

 

[John Shriver]

Lenses like the 90/4 Elmar and 135/4.5 Hektor, which only have a narrow coupling cam, are the ones that you want to focus close when going on and off a FSU rangefinder camera without a roller.