[Leica] Rangefinder flare, disappearing 90mm frameline

["Peter A. Klein" <pklein@2alpha.net>]

My M4-P does flare, unlike Thomas'.  But a far more annoying problem is
that the right edge of the 90mm frameline often dims out or disappears. 
It seems related to the angle of light hitting the illumination window. 
But the only way I know to make it always visible is to move my eye
significantly right of center.  This happens with or without eyeglasses,
and none of the other frame lines do this.  Erwin (or anybody), do you
have any idea what causes this?  Is it a standard thing, or something
that can be adjusted?

As for flare, I've found the major problems are with backlighting at a
certain angle, like shooting with the sun just above the picture, or
indoors when a light source is close and a bit above.  By putting a
finger in front of part of the frameline illumination window, I usually
can eliminate the flare while keeping the framelines visible.

When I get home tonight, I'm going to experiment with some cut-up pieces
of Post-It Notes or the dreaded Black Tape.  I think that a rectangle
smaller than the illumination window could be placed so that the
framelines would still be visible, but the RF patch would be less prone
to flare. 

Another possibility might be a colored filter over the illumination
window (red or purple or magenta, anything but yellow).  This would dim
the flare (and framelines) and make the flare a different color than the
"good" image.

I agree that such gerry-rigging ought not to be necessary in a $2000
(new) camera.  But if this finder design has been around for 20 years
and still has the problem, it may be that Leica has made the best
trade-off they believe they can.

- --Peter