Leica M8 first problem that apperead to me was
backfocus on shorter and shorter focusing
distances, I mean infinity focus is perfect, short
distance focus is made behind the point you adjust
the rangefinder for. I tested M8 with 3 lenses 35mm
f2 + 50 noct + 75 f1.4 : all 3 lenses did backfocus
on short distance with perfect focus on infinity.
I could solve this "easily" (I did it a long time
ago with M4-P wich had vert. misaligned RF + front
focused RF). Here is how, but be careful, this
operation can normaly only be made by a certified
Leica reparator. If you do it, it is at your own
risk. You could probably loose your waranty with
such an operation, or even worse, damage your
Bakfocus on short distance comes from a too short
focus sensor lever. To adjust it :
0. before making any adjustement to the RF be sure
that your lense(s) focuses perfectly on infinity
(very easy to test with a digital camera : 1. put
the lens to the stop on infinity, whatever
rangefinder is indicating, 2. take a picture of an
object very very far away, 3. check sharpness -
result should be perfect). Problem in focusing
precision could come from a lens whose RF barrel is
not properly adjusted for infinity. I have got this
happening with a Summilux 75mm.
1. loosen just a little bit the screw which secures
the lever on its shaft with a screwdriver (I
modified a normal screwdriver to be oblique, so
that it fits better the screw at an angle)
2. Turn the ring surrounding the screw by a little
amount in the screwing direction, so that the lever
is moved to the left.
3. Tighten center screw.
4. The effect of changing lever length is that it
changes the angle of the arm with the RF lens
barrel and so changes lightly infinity RF position.
That's why there is a screw (allen) in the center
of the focusing wheel. Adjust it to get a perfect
5. You are ready to make new tests. If it's not OK
you can repeat above steps.
The amount of "move" of the lever depands of the
amount of backfocusing. The best is to go with very
little paths until you reach the perfect focus.
Again, this procedure is a micro-mechanics
operation. Don't go in this procedure if you are
not familiar with micro-mechanics, and just
send camera + lenses to Leica for