Locus 1.0 by Harris Tech tries to take the guesswork out of getting the image you want by converting the old-school Depth of Field and Circle of Confusion (COC) formulas for digital cameras.
Locus 1.0 could be useful to a landscape photographer or to those who want to know the specifics of Circle of Confusion and all its calculations. But, to use it on the job, you would need access to a computer in the field. There are many advanced concepts at work, which could make it a good learning tool for beginning photographers. The price is not unreasonable for someone who really wants the mathematical information (licenses are available beginning at $30, direct).
Under the edit menu, Locus has specialized calculators.
There’s a COC calculator that fine-tunes the COC formula, and a Crop calculator that allows adjustment of output size to ensure a high quality print. The Focal Length calculator adjusts for viewing distances other than the standard 16 inches, and a Speed calculator helps determine the optimal shutter speed to avoid motion blur or camera shake.