P3D zoom lenses

[Michael _ Kaplan <mkaplan@xxxxxxxxxxx>]

I've used zoom lenses for years without a problem.

The best way of synchronizing focal lengths is to use a pin-registered
test-pattern slide. Offhand, I don't know who sells these, but they could
easily be made on a copy stand.

As to polarizers, I use conventional glass polarizers in rotating mounts,
taped to the front of the zoom lenses. While not the ideal optical
position for polarization, front mounting precludes depolarization by the
film, glass mounts and lens optics. The glass sandwich provides a easily
cleanable filter that doesn't warp (as plastic polarizers tend to)  and
resists scratching. The rotating mount enables precise adjustment after
the zoom lens has been set for the desirable focal length.

Images projected with this system are sharp and have a minimum of
ghosting.

BTW, from my experience, Ektagraphic III-A projectors with the standard
100 - 150 FF zoom lens can be obtained for around $300.

==========================================================
Michael Kaplan
View*Productions
Publishers of "Bruce Goff: 3 Houses" in View-Master stereo
view@xxxxxxxx  


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