[Leica] Ir filter and film cameras, take it off

[red735i at earthlink.net (Frank Filippone)]

The last word from Schneider Optics themselves on the 486 filter......
----------------------------------------------------
IMPORTANT NOTE REGARDING WIDE-ANGLE LENSES.

Please note however that, in contrast to mass-colored (integrally colored) 
filter glass, the UV-IR barrier filter is based on
thin-film technology. More than 30 interference coatings are vapor-deposited 
on one side, while the opposite side is MRC-coated. In
wide-angle lenses, the laws of physics lead to shallower incidence angles 
for peripheral rays. For geometric reasons these rays have
to travel further through the interference coatings than rays traveling 
vertically through the coatings in the centre of the lens.
With increasing angle of incidence, this leads to a change in light color 
towards blue. This effect can clearly be seen by looking
at an UV-IR barrier filter from an angle. The color of the reflected light 
changes, with a similar effect on the light traveling
through the filter.

The filter is therefore not suitable for lens systems with an angle of view 
of more than 60?
--------------------------------------------------------
Guess I was suspicious, right and wrong all at the same time.  Now to figure 
out which of the Leica lenses have an angle of view of
more than 60 degrees......  Anyone interested?

If you want  the entire specialized word file sent to me by Schneider, 
please email me directly.....

Frank Filippone
red735i@earthlink.net