Re: [photo-3d] Digest Number 471

[k0mz@xxxxxxxx]

>    Date: Fri, 16 Feb 2001 22:28:27 -0600
>    From: "Michael Galazin" <rexlion22@xxxxxxxxxxxxx>
> Subject: full format with image splitter?
> 
> Hi gang,
> 
> Are there any 35mm cameras built with a wider format than 
> 36x24....say,
> about 50x24 or even a72x24?  If such a camera (perhaps built with 
> panorama
> shooting in mind) had a splitter attached to the front of the lens, 
> one
> could obtain pairs of realist format 24x24 or perhaps even full 
> format 36x24
> shots, through a single lens.
> 
> Another possibility: What would happen if one attached a splitter to 
> a
> medium format camera, then trimmed the top and bottom of each frame 
> to
> create the above format stereo pairs?
> 
> I've just been curious about these possibilities.  Seems like a 
> more
> efficient, (mechanically) more trouble free, and possibly less 
> expensive way
> to go than an RBT camera.  What do you think?
> 
> Best regards,
> 
> Mike Galazin
> 
> 
Hello Mike.
Some time ago I was hoping to get the same thing from my Pentax stereo
mirror attachment.  I experimented with wide angle lenses and quickly
found that the mirror angles must work within a narrow range of focal
lengths in order to work.  I also found that it isn't designed for
anything wider than a 50mm lens for 35mm format normal sized 36mm frame
width.  I also found that unless the attachment is close to the front
element, severe vignetting occurs.  Then i drew the geometry of light
rays on a piece of paper to see what it would take to use a 35 mm wide
angle lens.  I found that the front mirrors of the attachment would have
to be so big to avoid vignetting that it would be about twice as big as
the Pentax unit.  The angle of the mirrors would have to be different to
make the images line up using a 35mm lens.  It is possible to make one
but to my knowledge, nothing is available on the market.
These things will work on large format cameras as Mamiya made one for
their Super 23 to be used with their 127 mm lens.  The mirror angles are
not quite right for a 50mm lens on 35 format though but the images are
not that far off.  If the taking angles of various formats match a 50mm
lens on 35mm format, they will make similar stereo pairs on different
formats.  The root of the problem is that they all make such narrow
iimages.
Robert J. Vaughan