Originally posted by slomojoe A 14mm focusing 6 feet away on a K20D has a dof of 1.16 ft-infinity at f22, 1.5 ft-inf at f16, and 1.94 ft-inf at f11. Unless you really need to capture something in that interval 1.2-1.9 feet away from the lens, the dof really makes no difference, and your subject's sharpness is going to be much greater at f 11.
Things are different with a less extreme wide angle. With a 24mm in the same conditions, you'd have dofs of 2.5-infinity and 3-inf at f22 and f16, but limited to 3.5-20.6ft at f11.
Here's a handy calculator:
Online Depth of Field Calculator I would be very careful with using a DOF calculator for that sort of things and there is a couple of reasons for that.
The DOF makrings we see on lenses were IIRC defined by Zeiss for 35mm format and with a 6x4" photo in mind.
Now DOF is not only about aperture, but also about viewing distance and printsize.
Thus in order to make that calculation you need to know your intented output size and and closest viewing distance to make sure that the above actual holds true.
Secondly the above calculation defines a zone where things appers to be in acceptable focus, that is not the same as in focus.
Thus the reason for some people to shoot stopped further down than the standard DOF calculator implies would be necessary is not necessarily because they do not know what they are doing, they just might have different printsizes and viewing distances in mind for their intent output than the standard DOF calculation is based on.