RE: [Leica] Depth of field summary with regard to the argument at hand

["Austin Franklin" <austin@darkroom.com>]

> Perceived depth of field varies with the magnification of the subject
> (combination of output size and viewing distance), not with the actual
> physical size of the subject.

But, it is the word 'perceived' that I have trouble with.  If you are going
to throw perception into the equation, then perception will vary with
conditions, and one of those conditions IS the size of the object, separate
from the magnification it is printed at.

A picture of a tree, up close...and looking up...it occupies almost the
entire width of the bottom of the image, and obviously tapers off to the
top.  What 'appears' to be in focus will 'appear' to be in focus from a
greater distance, than say a picture looking down the street.  The size of
the object does relate to what 'appears' to be in focus.

Eye charts are viewed from one distance, yet, the smaller characters on the
eye chart are 'out of focus', but the large objects are in focus, as far as
our eye is concerned.