[MF3D.FORUM:50] Re: Apparent image size, MF verus

[Alan Lewis <3-d@xxxxxxxx>]

Bill Glickman wrote:
>  I compared your Saturn to a $20 3d discovery viewer... and the
> higher magnification lenses of the 3d discover made those small 35mm slides
> appear larger than the sputnik slides in the Saturn viewer. 

Does anyone know what f.l. the Discover viewer uses?  There was some
talk about this last year I think.  I believe the lenses may be aspheric
in design.

Using full frame 35mm with higher magnification viewer lenses will work
fine.  It is all in the quality and size of the viewer lenses though. 
The failure of many mass produced stereo formats is the misguided desire
by the manufacturers to use cheap lenses that are too small in diameter
and that have distortions.  Why use a $3000 camera and then view the
results in a $20 viewer.  It does not make sense.

The challenge to magnifying full frame 35mm to get an immersive feel
will be the viewer lenses.  So far I have been able to get a 47mm f.l.
achromat combination with a dia. of 30mm in my full frame viewer.  This
makes for extremely comfortable viewing for almost all people.  But it
does not feel immersive.  

My gut feel is that you would need a viewer f.l. of around 40mm to get
an immersive feel.  At this f.l. using standard single achromatic lenses
you will be limited to about a 20mm dia.   Not big enough in my opinion.
But using two 75mm f.l. lenses paired would achieve the 40mm f.l. and
allow for a 30mm + diameter.

Perhaps this could be accomplished using two DCX lenses for economy, or
the modern aspheric designs.

-- 
Alan Lewis  
mailto:3-d@xxxxxxxx
http://members.home.net/3-d
Serious viewers for Serious viewer's
New stereo viewers & Stereo Wedding Photography