rangefinder cam and elmarit 90 with M2

[blacktaped]

Hi

I have an old elmarit 90 from 1960 and noticed one little thing lately:
basically, when I put it on my M2 body, it will engage its cam with the rangefinder control arm and wheel of the camera only if the focus is at a close distance (i.e. when the cam of the lens is laying in) but not when it's at infinity (i.e. when the cam sticks at its highest position). Notice that my M2 engages always fine with the other lens, at all focus positions.
On the other body I have, an M6, all lenses engage properly at infinity, even the elmarit.
So, by a deeper observation (i.e. opening the back door and inserting the lens with the curtains opened shooting at "B") I noticed that the rangefinder wheels on the two bodies are placed at a slight different height, i.e. a bit higher in the M2 (so that it doesn't engage the elmarit at infinity) than in the M6.
What is your opinion or experience in the matter? I mean, is that a problem of the lens cam or is this due to the slight different position of the wheel in the M2?
Please note that the M2 is always been working fine with all my lenses (elmarit included, when properly engaged), in terms of focus accuracy, and so has the M6.

Thanks for your help

 

[former member]

I've had problems with RF wheels being too low and slipping under a thin Cam on the lens. If the wheel on the M2 is so high that it is slipping over the Cam of the Elmarit at infinity, I'm surprised it works well with other lenses. This can be corrected by a CLA, and you could contact Youxin Ye. I would send him the camera and lens if you choose to have it corrected.

 

[blacktaped]

thanks Brian

it is indeed a microscopical difference the one that I see in terms of heights of the wheels of the two bodies, all other lenses have a circular cam that sits apparently in a perfect manner on both wheels (M2 and M6).
The point with the 90 is that it has instead a "tooth-shaped" cam that is not perfectly aligned with the wheels, and particularly doesn't engage the M2.
The M2 has been CLAd very recently, so I guess it's just a question of servicing the lens.
However, I don't think I'll be using the lens since I fear that this misalignment would seriously harm the wheels of both bodies, which really scares me... 😱

 

[former member]

It sounds like the Cam on the lens is misaligned. Otherwise, if it engages at one distance, it should be good for all. The Cam should move straight back and forth, not at an angle. My 13.5cm f4.5 Hektor and 13.5cm f3.5 Nikkor are both like this, and work perfectly with the m3 and M2. If the Cam moved at an angle, it would be a problem.

 

[awilder]

I have a mint 90 AA and a 135/4 TE with a similar single "member" cam design vs the circular cam seen on most other Leica lenses. One of them touches the TOP of the camera's roller and the other touches the BOTTOM of the roller with only about 1/2 mm to spare. This tells me that the roller height must be about right because if any higher or lower it might make better contact with one lens but will miss the cam on the other lens. The important thing is to check to see if the roller makes any contact with the cam, if not it needs adjustment. Apparently for what ever reason Leica has made in the cam design of these lenses, they are not designed to contact squarely in the center of the roller like the circular cams, but near the top or bottom. This is why they tell people not to push up on the roller when adjustng the screw for focus as you might change the cam roller height.

 

[nobbylon]

Easy fix! just fit the 90, set at infinity, open the shutter on B and bend the arm down until the roller sits on the lens. I had to do this on one of my M2's

 

[blacktaped]

thanks nobbylon!
this is exactly what my cla-man of trust has doen this afternoon, after I brought him my M2 and the lenses: he just said "no worries, the whell needs just a small calibration" which looked an easy thing in his hands, since the wheel arm, apparently, is flexible for calibration purpose. (although I would never try doing it by myself...)😉