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

[John Collier <jbcollier@home.com>]

Interesting quotes from the DOF article:
- ---------
It should be realised that "seeing" a thing is not the same as "resolving"
it.

The fact that the eye cannot distinguish between a point and a very small
disc of light leads to the concept of "depth of field".
- ---------


Depth of field is an illusion of perception and is not fixed at any stage of
the photographic process as it is easy to change the viewing distance which
varies the image size of the final output or intermediate stages.

Now way back to the original argument that the film format has no effect on
the perceived depth of field a lens produces. As the size of the film format
used with a particular focal length of lens affects the size that a subject
will be reproduced, the larger the film format gives a smaller subject size
in a standardised final output as compared to a smaller film format, it is
an important factor in calculating the depth of field.

It is possible to reproduce exactly the same potential depth of field using
different film formats, the same lens and subject distance, but, this can
only be done by discarding the extra size of the larger film format which
does not strike me as logical nor can it be considered common practice.

If you disagree, please refute the above statements by referring to the
original posted article, or post another, as this allows us to proceed with
common terminology and background.

Thank you B.D. et al for your patience,

John Collier