Flash Guide
Flash exposure calculator for film photographers
Flash Calculator
Calculate flash distances using guide number and camera settings
Guide Number (GN) at ISO 100
Units
Meters
Feet
Table Type
Distance vs ISO
Distance vs Power
ISO Values (comma-separated)
ISO 50
ISO 100
ISO 200
ISO 400
ISO 800
ISO 1600
F-Stop Range
Min f-stop
▲
▼
Max f-stop
▲
▼
Step
Show Chart
Calculate Flash Distances