Manual Flash Calculator

National Photographic Services

About this app

Manual Flash Calculator (Free Edition) provides a handy utility for accurately determining flash-subject distance. It's quick and easy to use for tricky lighting situations and backgrounds, where TTL auto-flash can often struggle.

This app is ad-free, and requires no special device permissions or network connectivity.

Key Features:
• Aperture range F/1.2 to F/22
• ISO range ISO50 to ISO6400
• Flash output ratios to 1/256 power
• Flash exposure compensation to 5 EV
• Zoom support for unlimited guide settings
• Power increments in 1/3, 1/2 or Full stops
• Macro closeup distances (in and cm)

Set the guide number/zoom coverage, power-ratio limit, power adjustment interval, and guide number units for your flash. (You can find this information from the guide number table in your flash user manual).

If you own more than one flash unit, please consider supporting this project by upgrading to Manual Flash Calculator Professional. It supports saving an unlimited number of flash configurations. And it costs less than the price of a cup of coffee!

Ratings and reviews

I don't really understand this app. I'm not sure what it's trying to tell me, lol. There are no instructions, although I shouldn't need them. It's just a simple formula. Why all the extraneous stuff? I found a much simpler calculator that gives you either the distance if you enter the aperture or it gives you the aperture if you enter distance. The only other thing you enter is the flash's guide number and the ISO.

Works well, but switching from meters to feet doesn't actually change the displayed number. I.e. if you have distance of 5m, switching to feet will render distance of 5ft. would be nice if this was fixed for those of us who can't visually determine distance using the metric system.

For the price, this app ticks all my boxes. Well done. I use it with my medium format SLR film camera, primarily for macro or near macro. Suggestions? Since MF or LF lenses tend to have rather tiny minimum apertures, e.g., f32 or f45, I'd love to see these two f/stops added to the aperture range slider. Even better would be some sort of extension factor, i.e., additional stops needed based on length of extension (tube or bellows).

What’s new

Fix bug with edge-to-edge layout in Android 15 (SDK-35)