Re: Stereo Macro (more realistically)

[P3D John Bercovitz <bercov@xxxxxxxxxxx>]

Here's what happens when I balance geometric and physical optics
to maximize system resolution.  I also now give results for very
very fine resolution of film/lens (60 lpmm) and what I consider 
more typical (40 lpmm).  As you can see, things are now not so bad
as they were, at large depths of field.  Basically, I opened up the
lens to ameliorate the diffraction problem but at the expense of the
geometric problem.  Best is achieved at the balance.

The results are that medium format still has the slight edge for
what we're considering right now.  This is to say nothing of the
enormous edge that medium format has when it comes to actually
viewing the result.  It's one thing to take a picture with a 5-p
camera that has 35 mm lenses but entirely another to actually view 
it at 35 mm.  Usually you'll have to view it with a longer lens,
say 42 mm, therby converting your normal field of view to a 
narrower field of view.  On the other hand, if you take a picture
with an 80 mm lens in medium format (actually a wider view to start
with than 35 mm in 5-p format), it is trivial to view it with an 
80 mm achromat from Edmund Sci or similar.  So you get a much 
wider view with a cheaper viewer in medium format.  You can have
almost as wide a view with an extremely expensive viewer in 5-p.

Quantitative results
     geometric res set equal to diffraction
     give film/lens res 40 lines per mm
     give film/lens res 60 lines per mm

Miniature format (26.7 mm lens, subject dist = 80)
                                                 40        60
near     far      maximum    lens      eff.      sum       sum
dist     dist     st base    f/no      f/no      res       res

70       90         10        46        69       5.6       5.1
72       88         13        40        60       5.2       4.6
74       86         17        35        52       4.8       4.1
76       84         26        29        43       4.3       3.6
78       82         53        19        29       3.8       3.0
79       81        106        14        22       3.5       2.6


Medium format (40 mm lens, subject dist = 80)
                                                 40        60
near     far      maximum    lens      eff.      sum       sum
dist     dist     st base    f/no      f/no      res       res

70       90         10        68       139       5.1       4.8
72       88         13        60       121       4.6       4.3
74       86         17        52       104       4.0       3.8
76       84         26        43        86       3.6       3.2
78       82         53        29        57       3.0       2.5
79       81        106        22        43       2.6       2.0

John B


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