Adapter or lens?

[AgentX]

Could a ltm lens-to-m-body adapter be the cause of my rangefinder focusing past infinity with a specific lens? (Unsure of where the lens is actually focusing, just that the rangefinder will focus from near to an infinity distance object, then the patch will continue to move past it until the lens rests at the far focus limit.)

Rangefinder is calibrated fine for 3 other Leitz m-mount lenses. I have no other LTM adapters or lenses to help diagnose.

Or must the problem with this lie in the lens? I'm unfamiliar with the mechanics of what-actuates-what with this system.

Thanks!

 

[Chriscrawfordphoto]

If the adapter is too thin it could let the lens focus past infinity

 

[ferider]

Yes. Which lens, adapter & camera ?

 

[elshaneo]

Yeah indeed, get instead a quality adapter like the Voigtlander adapters ;-)

 

[AgentX]

It is a voigtlander adapter...

CV 21mm, voigt 28/90 adapter, M3 body.

I know that if the adapter's not within spec, the lens won't focus where it should (where the RF is indicating, on a system where everything's working).

But could it cause the rangefinder to do what it's doing when the lens is mounted, or is actuating the RF purely a function of the lens?

If I had another LTM lens to test out and see if the RF problem was consistent across two lenses, I could easily answer this myself. But I'm a little beyond the geography of a camera shop out here, especially one with an LTM mount lens in the case!

 

[SimonSawSunlight]

this is indeed a little weird, I've never had this kind of problem with my vc 4/21 + original VC adapter... then again, at 21mm it is not really that much of an issue, is it?
have you always had this problem with that lens?

 

[AgentX]

Yeah, it's a new lens right out of the box...the adapter was listed as used, but looked entirely new. Been like this since I opened it up.

 

[payasam]

"But could it cause the rangefinder to do what it's doing when the lens is mounted, or is actuating the RF purely a function of the lens?"

The adapter does not move: the cam at the rear of the lens bears upon the cam follower in the camera body.

Possibly the easiest method of diagnosis is to mount lens and adapter on another M mount body and see what happens.

 

[ferider]

It happens sometimes in particular with the M3 due to large magnification. I assume it's just a little.

Basically camera and lens are each borderline within tolerances, but the combination is not.

Note that I always have thought that CV type I adapters are very slightly thinner when compared to type II or original Leica adapters.

Test the lens, most likely it's a no-issue optically.

Roland.

 

[AgentX]

Hm, the rangefinder's overfocusing seems to be a little more than "just past" at infinity...

That said, with a 21mm lens at a min f/4 aperture, it seems to be close enough.

Thanks all for the assistance. While I know the adapter doesn't move or have moving parts, I was wondering if perhaps the manner in which it positions the lens could cause this. I'm guessing the problem is in the lens. However, I do need to get a 135mm lens adapter for another LTM lens which is showing up soon. Looks like I've found an original Leitz.

So I guess I'll be able to try both lenses on both adapters and see if I can narrow down the problem. I honestly forgot I had the new lens coming! Saw it in the classifieds here late at night, ordered it, then it slipped my mind.

 

[AgentX]

Wow, a Nikon LTM 135/3.5 is a SERIOUS chunk of metal and glass. And it focuses perfectly with my rangefinder using the same LTM/M adapter. Can't wait to try it out!

B&H won't exchange the lens (it is about a month and a half later, so not too sound harsh on them...lens is unused, however) and directed me to CV for warranty service. We'll see what they say.