13 Jul
1999
13 Jul
'99
8:14 p.m.
Max Eskin <max82(a)surfree.com> wrote:
On Tue, 13 Jul 1999, Chuck McManis wrote:
Hi
It is determined by the f/ratio
and the color that you are trying to focus. It is a wave property
of light. A point sourse of light can only be focused to certain
disk size. The Airy disk is defined as 1.22 * wave_length * f_ratio.
The smallest distance that one can call two disk as being
separate is call Dawes criteria and is when the two spots
are 1 Airy disk apart. Other shapes of objects will have
sightly worse problems of separation but this is a good rule
of thumb for light.
It is interesting that stopping a lens down, makes a higher
f/ratio and makes the spot size smaller. Stopping the lens down
also improves depth of field. Exposure time also goes up.
You just can win.
Dwight
That question will fry your brain. It depends on
what film you use, what
speed you shoot it at, and what process you use to develop it.
But, isn't there a maximum resolution?
--Max Eskin (max82(a)surfree.com)
http://scivault.hypermart.net: Ignorance is Impotence - Knowledge is Power