Re: Nishika Macro

[P3D john bercovitz <bercov@xxxxxxxxxxx>]

LeRoy Barco writes about macro:

> The "one in thirty" rule can be jettisoned for this kind of work... 
> it all depends on your (and your audience's) toleration for the 
> amount of depth in the image... the closer you get, in general, 
> the less depth you'll want in your scene... and the less DOF you 
> have, too.

This is good advice.  The 1 in 30 rule applies to normal stereo pix
taken with infinity in the picture.  Two criticisms of it, though: 
1] it is a degenerate form of the rule that says that the on-film 
deviation shouldn't exceed 1.2 mm (1/30 of the focal length of the 
system) and 2] both the 1 in 30 rule and the 1.2 mm rule are too 
conservative under many conditions, especially those which have a 
gentle change in depth, the extreme example being a picture of a 
featureless grassy field with infinity at the top of the frame and 
something very near at the bottom of the frame.

John B


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