Quote Originally Posted by Alan
Film? That's a different story. F/16-22 will give sharp images with a deep DOF, but not a digital camera. Not yet, at least.
Diffraction is an optical effect, it is not affected by capture mediums. The size of the capture medium (e.g. APS-C vs FF35) only comes into play in that larger mediums have lower reproduction magnification, so narrower f/stops may be used. People think it is different for film/digital because of at least two reasons:

* Digital sensors are usually much smaller than film (e.g. APS-C), so magnified more for display.
* People routinely examine digital at much higher display magnifications than film.

For example, people routinely examine digital photographs with 100% crops, whereas they never printed their film negatives to the same size (a 5-foot-wide print).

Quote Originally Posted by Alan
I'd rather have a better image quality, then a lousy one with a great depth of field.
I'd rather have an image where the entire shot is slightly blurred by diffraction than one where only some important parts of the image are in focus, but other parts are heavily blurred by being out of focus because it's not within the depth of field.

To me, the subject and composition are far more important than resolution and contrast. If I am struck with the idea for a composition of a certain subject that requires f/22, I will not hesitate to use it. I lose resolution and contrast to diffraction, but I gain a composition/subject that would not be possible to photograph at any other f/stop.