Manual Flash Calculator

187 reviews
Content rating
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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!
Updated on
Sep 10, 2023

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
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No data collected
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Ratings and reviews

178 reviews
A Google user
March 10, 2020
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.
3 people found this review helpful
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Chris Hunt
October 22, 2021
Relatively new to flash photography but in my rather limited experience 8 know the distance of the flash to subject it's the power setting for the flash that's variable. I realise you can move the sliders to get the distance you want but wouldnt it be easier to set the distance as a fixed value and have the flash power as the variable?
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Terrence Branscombe
December 3, 2020
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).
4 people found this review helpful
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What's new

Upgrade to support Android SDK-33