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