[MF3D.FORUM:1233] Re: Loss of detail in projection

[Richard Twichell <rmt@xxxxxxxxxxxxxxx>]

Dr. Dave writes:

> I fully standby my statement that all FINE detail that is 
> present in a hand viewer is lost in projection. IMHO this is 
> from three factors: 1) incomplete exclusion of the images 
> (ghosting or cross-talk or whatever you want to call it) 2) 
> dimmer lighting 3) critical focus (from the projector lenses, 
> from the lenticular screen, from enlargement, and mostly from 
> projectionist error).

This may often be the case, but need not be so. Ghosting will be minimal
if the photographer is experienced in shooting for projection and avoids
high-contrast situations by controlling exposure and lighting.  Screen
illumination should be maximized by using the brightest available lamps,
clean optics, new polarizers, and absence of ambient hall light. 
Perhaps the most important factor in preserving projected detail
(resolution) is lens quality.  The difference between the usual
Ektagraphic lenses and high-grade optics from Schneider, Rollei, or Buhl
is remarkable. Lenticular screens degrade resolution particularly in
small-screen setups where seating is relatively close.  "Silver"
non-lenticular screens are rare in small sizes but can be found.
"Projectionist error" is often photographer error - poor mounting causes
focus and alignment problems which are generally avoidable except in
"judging" situations where various photographers' work is presented. 
Apparent enlargement at the ortho seat should be the same as that with
an ortho viewer.

Projection is often not as good as it could be, and should be.  If the
object of the exercise is to count the whiskers on the cat, the
hand-viewer will win every time.  But high-quality large screen stereo
projection, when everything is "right", where a "stereo-smart" audience
is sharing the simultaneous experience, has an impact of its own, which
cannot be matched by the inherently  solitary hand-viewer.  A different
stereo viewing experience, not better, not worse.

Dick Twichell