P3D Re: Circle of Confusion

[Eric Goldstein <egoldste@xxxxxx>]

Greg Wageman wrote:

> My personal M.O. when shooting stereo is to select the largest f-number that
> still gives me a reasonably fast shutter speed for the conditions

Resolution-hungry stereo photography actually creates an interesting
push-pull dynamic with regard to DOF versus resolution, in that lens
performance is typically best at f/8ish for tessar types and f/11 for
triplets, but DOF keeps improving the smaller one goes. Personally, as I
am not a particularly depth-hungry shooter, so I try for f/8-f/11 IF I'm
looking for broad areas of focus...

George T and others conducted a very useful discussion on this list
several months ago raising the point that, as Greg says, truly only one
plane of the composition is "in focus" and while DOF tables indicate
that "acceptable" focus extends along the z-axis from this plane, the
particular composition you are shooting may be compromised by having a
critical foreground component only acceptably sharp, while some
insignificant object behind is critically sharp. 
Selective focus is an important tool for the creative photographer to
control the composition and indiscriminate or automatic use of "the
smallest aperture possible" and hyperfocus works against it...


Eric G.


------------------------------