Silverlog Flash vs FlashCalc

Silverlog Flash calculates flash exposure using guide numbers — the fundamental relationship between flash power, distance and aperture. HOW IT WORKS Choose what to solve for and enter the other two values. Find the aperture for a given flash-to-subject distance, the maximum distance for a given aperture, or the guide number from a known distance and aperture. Adjust ISO to see how sensitivity affects your working range. FEATURES • Guide number to aperture calculation • Guide number to maximum distance calculation • Guide number from distance and aperture • ISO adjustment • Metric and imperial distance units • Works offline — no internet connection needed • Clean, focused interface • Dark mode support USEFUL FOR • Manual flash photography without TTL • Working out flash-to-subject distance for off-camera flash • Understanding your flash's effective range at different apertures • Film photographers using manual flash units Part of the Silverlog photography toolkit. No account required. No data collected.

FlashCalc is a manual flash exposure assistant designed for photographers who shoot with on-camera and off-camera speedlights. Whether you are balancing flash with ambient light or shooting entirely manual strobes, FlashCalc helps you dial in accurate exposures without guesswork. KEY FEATURES: • Dual Calculation Modes: Calculate required Flash Power ratio (1/1 to 1/128) based on your chosen aperture, or calculate recommended Aperture (f-stop) for a target power. • Speedlight Zoom & GN Memory: Assign and save guide numbers across flash zoom positions (24mm to 105mm+). • ISO Compensation: Automatically scales guide number outputs for different camera ISO values. • EV Offset & Fraction Accuracy: View precise 1/3 and 1/10 stop EV offsets and calculated physical ratios. • Rapid Distance Nudge: Quick stepper adjustments for subject distance in meters or feet. • 100% Private & Offline: Works without internet or camera tethering. No tracking, accounts, or data collection.