Dept of Field Data

[cls]

Print size wouldn’t matter as far as the calculator goes. The camera does know focus distance, it displays this in the exif files with some programs. My near sightedness doesn't affect the DOF of my pictures. I think it is easily implemented, and should be as accurate as the ones that are on-line. On-line calculators only need to know a few things; lens, aperture, distance and sensor size. All of the pieces of information are available in camera.

Yes, but when they need to know sensor size it's because it is put in to the "magnification factor" calculation (from sensor size to the assumed print size of 25 cm / 10 inch long side). The assumption of the viewer's ability to distinguish 5 lp/mm at a viewing distance of 25 cm is also built in (typically these parameters are not inputs to DOF calculators). But sure, the same simple algorithm as can be found in various DOF calculators could be implemented also in cameras. But the result would still be based on assumptions.

[HDNitehawk]

Yes, but when they need to know sensor size it's because it is put in to the "magnification factor" calculation (from sensor size to the assumed print size of 25 cm / 10 inch long side). The assumption of the viewer's ability to distinguish 5 lp/mm at a viewing distance of 25 cm is also built in (typically these parameters are not inputs to DOF calculators). But sure, the same simple algorithm as can be found in various DOF calculators could be implemented also in cameras. But the result would still be based on assumptions.

That would be true, since the DOF is subjective. Any calculator you have will be the same.