Depth of Field Calculator
This is a depth of field calculator intended for use in photography.
It is implemented in javascript so once you have loaded it in your browser it operates locally and does not need a network.
It is really just a learning exercise / proof of concept that got a bit carried away. It may well be flawed, and if it is, I'm sorry.
It has some handy keyboard shortcuts, but it really aught to work nicely on touch interfaces, which it doesn't. Maybe another day ...