In Focus Does Not Always Mean Sharp
(c) Copyright 2009 David Dilworth
More Depth of Field means Fuzzier Images
Most photographers don't learn all the important parts about focus. They learn how to focus a lens once they have a scene framed and they learn to maximize "depth of field"; stretching the range of near and far objects "in focus" by narrowing the aperture hole (increasing the F-stop) as much as possible.
What is not widely appreciated is that smaller apertures make images less sharp. Many photographers, including some experts, mistakenly believe that making an aperture smaller has no effect on image sharpness. Taking that to an extreme was the Group F/64. (F/64 is the tiniest aperture on large format cameras, barely larger than a pinhole.)
This group was perfectly well-intended because at that time (the 1930s) fine art photography valued soft images - not sharpness (called the California Pictoralist movement), which contrasted with this new group's goal of sharp, clear images.
However, there is a downside to tiny apertures; a serious optical phenomenon that makes your images fuzzier as the aperture size and sensel (pixel) size on your digital sensor chip gets smaller. It is called . . .
(This is only a taste of the full article, which is in preparation for commercial publication.)