Re: [Leica] Leica Users digest V16 #75

[Javier Perez <japho@cunyvm.cuny.edu>]

> Date: Sun, 26 Mar 2000 20:50:24 -0800
> From: "Stephen Attaway" <attaway@slip.net>
> Subject: [Leica] Horizontal Rangefinder Adjustment on M - what is the secret?
>
> Esteemed LUGers:
> The rangefinder on my M4P is off by a tiny bit at infinity, just enough to
> notice two lines where only one should be when focused on a distant
> flagpole. I sent it in to Gasser's, who checked it and said it looked ok.
> Yet it still bugs me. Does this small error make any practical difference?
> Its pretty clear to me the adjustment is not made in the same way as a IIIf
> or a Canon7, as there is no adjustment screw where I expected to find one.
> I looked up rangefinder alignment in the archives, and found that the screw
> that was not there would have adjusted vertical alignment, had I owned an
> M4, M3 or M2. So I am glad I did not find it, in a way. Someone, I believe
> it was Mark Small, stated that horizontal alignment was "user adjustable and
> required a special tool". It looks like there is an arm to adjust an
> eccentric on the pivot for the rangefinder cam.
> Can anyone tell me the procedure for adjusting horizontal alignment on the M
> and what special tool is needed? Of course if the procedure is to ignore
> small errors until a CLA, I can live with that.
> Kind regards,
> Stephen Attaway

Howdy

Here's what works for me. I don't know how Leitz does it.

First ascertain that both images are focused with respect to each other.
This is done by focusing slightlty ahead or behind a vertical object and then
shifting
the position of your eye left right up and down within the eyepiece. The two images
should not
move with respect to each other. If they do, turn the threaded lens in or out until
the images
are stabilized. I have an M6 came right from of the factory with this problem as
well as off
parallel curtains!

There are 2 adjustments that affect horizontal position. The first being an
eccentric on the
rangefinder pivot which regulates cantilever length. A second ecentric is on the
rangefinder wheel itself and controls cantilever angle with respect to the lens
focusing position. Both are accessible once the lens is removed. The trick is to get

the right angle at infinity by adjusting the wheel eccentric until the images
coincide
exactly and then focus on a closer object and check focus there using either a spare

focusing screen or a reference camera. Adjust close focus by turning the cantilever
eccentric.
Now refocus on infinity and pray that the alignment is still perfect. If it's not
repeat the process zeroing in until both ranges are ok or until u go nuts.

There are other factors which can affect horizontal alignment. One
is the position of the rangefinder itself. It can be moved front or back ever so
slightly
by loosening the 2 screws under the rewind end of the chassis as well as the one
right
behind and under the rangefinder wheel. The position of all glass will also affect
the focus.
The angled magnifier can be pushed in or out to change both horizontal and vertical
image but should not be touched unless the camera has been knocked real hard. The
front
element can be shifted left and right but it's also set at the factory and shouldn't
be touched.
Ditto for the prism It's major surgery and can keep u busy all day.

Finally, if the infinity misalignment is within the depth of field on a long fast
lens at max
aperture and close/mid focus is ok, you're better off not touching it. Unless the
camera was
dropped, this was the point where the Leitz tech, who was using sophisticated
alignment tools, said ok. It's good to go. It's doubtful that any of can improve
upon that.

BTW: I've run in to some cameras that just won't align perfectly no matter how much
you fiddle with them possibly because the cam was malformed or is badly worn but
they are still within specs

*** Warning make sure that you support the rangfinder cantilever when adjusting the
wheel
       or better yet remove the cantilever entirely it to perform the
wheeladjustment.
       Excessive angular loading will kill the rangefinder bearinng and/or
cantilever instantly!

Lots a luck
Javier