On 2008-01-21, Blinky the Shark wrote:
Blinky the Shark wrote:

Whiskers wrote:

Physics. With the very short focal lengths that go with most 'amateur'
digicams (to get sensible angles of view with the tiny image sensors),
anything much smaller than f/8 will result in the diffraction of the
light rays hitting the edge of the apperture overwhelming the
un-diffracted rays passing through the centre of the hole, thus
degrading the image unacceptably.

Ah! Diffraction at the blades. I didn't realize that was an issue. I'm
used to abberations toward the outside of the lens -- but this is kinda
the reverse because it gets worse nearer the center of the lens axis. And
that's why I never thought of it.

And what did I just run across in r.p.digital?

q

You /can/ get the depth of field, but at apertures of f/16 or so and
smaller, diffraction softening comes into play. Just makes the image not
quite as sharp. I'm no expert, just what I've read.

/q

I love the Net.

So much quicker than going to the library and finding a book. But there
are books about 'depth of field' and lens abberations and so on, and why
Leica lenses are so much better than Zeiss (or not, according to taste)
and so on.

--
-- ^^^^^^^^^^
-- Whiskers
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