At their most basic, manual flash ‘dial’ calculators always contain distance, f-stop, and ISO. At some point in time, variable power flashes became available and that was incorporated into the flash calculations.

This is my attempt to add the extra zoom variable which, from a calculation standpoint, is a variation on the ‘power’ aspect. I wanted some way to calculate manual use of my Sony HVL-F42AM flash and this is the result.

I had some people ask for a similar calculator for the Sony HVL-F58AM. If you wish to make one, contact me and I’ll email a PDF with instructions.