P3D Re: VM lenses

["Dr. George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

>Since lens size is relative to format, what is the 35mm equivalent of
>the VM Personal's 20mm lenses?
    
Good question, Jeremy.  You can get the answer by working similar
triangles.  Since the "angle of view" is the same you can calculate
the distance of the lens from the focal plane, which is the focal
length of the lens:

        X = lens, 20 mm from film plane (VM), X mm for full frame
      /   \
     /     \
    /       \
   /         \
   -----------  Film plane, size = diagonal of 11x12 or 24x36 mm 

My calculations show that the 20 mm lenses of the VM personal
correspond to 50 mm lenses in 35 mm format.  So they are 
"normal" for this smaller size.  Same is approximately true
for the Realist format.  The problem that some people are 
having is that this small chip is viewed with longer lenses
(40 to 50 mm, instead of 20 mm) which gives pronounced stretch.

George Themelis


  


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