TrueDoF-Intro DoF Calculator 4+

I've shot controlled diffraction tests through all my cameras, and this seems quite accurate. The only thing I'd note is that it doesn't take pixel size into account. As the individual pixels on a certain size sensor decrease, the noticeable effects of diffraction increase.

Technically it looks about right, but they should specify that the depth of field is still increasing at f16, f22, and so on, even though the image is becoming blurrier, which is an important difference in macro photography where diffraction limited images may be objectively better because wider apertures result in too shallow of a depth of field.

4 out of 5 only because they're treating DOF and diffraction as the same thing, otherwise this looks good and works really well.

Simple. Useful. Accurate. Thank you.

A nice GUI design isn't everything. This app incorrectly shows depth of field decreasing above f/16 with 35mm format. That's not technically accurate: it's quite wrong. Diffraction, due to stopping down very far, does blur the image but does not affect depth of field. DOF continues to increase even as diffraction blur decreases resolution while stopping down. At some point the diffraction blur becomes bigger than the circle of confusion, which is chosen by the photographer for best results (or by textbook value or lens-maker value), but it affects all parts of the picture: at the plane of true focus, in the depth of field, and outside the DOF. At any rate, sometimes you need more depth of field than can be given by staying with your desired circle of confusion, so you may have to sacrifice some resolution to diffraction to get adequate (if less than optimum) resolution in front of and behind the main subject at the plane of focus. Also this app does not go down to macro distances like iDof Calc does.