Belplasca close-up adapter

[P3D Elliott Swanson <e3d@xxxxxxxxxx>]

Dennis Sherwood said:

If you use a mount capable of horizontal film adjustment, a VM close-up
set is not of much use.  If you want to get closer than one meter,
supplementary close-up lenses on series 5 push down rings makes more sense
and is much cheaper.  The real limit is as you get closer, when you try to
mount the film pair there might be light gaps, and the depth range become
too excessive unless you are very careful about shortening the background. 
Dennis Sherwood, proud owner of a Belplasca. 

Elliott Swanson asks:

But wouldn't you be able to retain the full 7p image with a +1 diopter
correction and a prism ("wedge") correction, working closer than 1 meter,
if you were willing to put up with some small degree of distortion? If you
use the Belplasca (BTW, I have a Belplasca and really like it also) at a
distance of 1 meter, the only way to mount the results-- without prism or
"toe-in" correction-- is to put the 7p image into a 5p mount with
horizontal adjustment, like an Albion or an RBT, and essentially give up
2p of the image. (And, as Dennis says, one needs to lose the background in
a hurry working that close.) Ok. Time to test the theory. I'll shoot a
roll of film and see how close the Belplasca/VM can be made to function
while still retaining a full 7p image that doesn't violate too many of the
rules of stereoscopy. 



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