Originally posted by dms My point was if you take some values from your DA lens you can see if they are: (1) consistent with older full frame lens, or (2) whether the 1 stop more closed is already included, or (3) if they are inconsistent with either of these. No matter what anyone says--the real test is in the numbers on your lens!

Another real test is to take pictures and evaluate the results. As Canada_Rockies pointed out, depth of field scales are guidelines based on a somewhat arbitrary set of criteria. Best to make some pictures, look carefully at the results, and if necessary establish a personal fudge factor to suit your own tastes.

None of the lenses I regularly use for digital have DOF scales, so I won't comment on APS format and DOF scales. I"ve been a photographer for a long time, so I rely on experience combined with DOF preview.

For 35mm film, I tend to close down one more stop than recommended by the DOF scale. Same for medium format, where my bodies are all rangefinders or TLRs.

Most of my 35mm and digital work is done in the f/8 to f/16 range. My personal style involves a high level of sharp detail in subjects that often stretch from a few feet away to infinity. I find that for 3-dimensional subjects the benefits of increased DOF outweigh diffraction effects in terms of apparent sharpness in that aperture range.

John