On 09/12/2012 5:07 AM, Larry Colen wrote:
In other words, with an AA filter, a 24MP APS-C lens will definitely be
diffraction limited by f/8.0. Without an AA filter, assuming that the lens is
sharp enough, diffraction is probably having an effect by f/4 or f/5.6.
Some people treat a diffraction limit as if it's a brick wall. It isn't.
Diffraction has always existed in the photographic world, and is just
one of many things that we juggle, and frankly, I've never felt
diffraction was something that ruined a print.
Lack of depth of field because the lens was too wide open has, at least
in my own work, ruined more images than because the lens was stopped
down past the "diffraction limit".
Shooting 4x5 film, one is often shooting at very small apertures,
invariably smaller than f/22, and most often much smaller than that.
My most used aperture when shooting 4x5 was f/64, which, even with a
150mm standard lens is well and truly into what computer age
photographers would consider mushville.
It was what I had to do to get the depth of field I needed, it never
seemed to cause me unsharp images.
OTOH, leaving the aperture open too wide was a sure way to ruin a picture.
Some of us run the numbers and decide something just couldn't possibly
have a chance of working, some of us go out and take pictures.
I suppose trotting out the old adage of bees being aerodynamically
unable to fly, but the bee, knowing nothing of aerodynamics keeps
zipping from flower to flower might be apt here.
--
William Robb
--
PDML Pentax-Discuss Mail List
[email protected]
http://pdml.net/mailman/listinfo/pdml_pdml.net
to UNSUBSCRIBE from the PDML, please visit the link directly above and follow
the directions.
