How to Calculate Flash Guide
What is Flash Guide?
A flash guide number calculator determines correct aperture and flash distance settings for photography lighting. Guide Number = aperture × distance. Higher guide numbers indicate more powerful flashes; knowing the GN lets you predict exposure without test shots.
Step-by-Step Guide
- 1Input parameters for calculation
- 2Apply formulas based on selected mode
- 3Review and export results
Worked Examples
Input
Sample values entered
Result
Calculated outcome
Results depend on parameter values
Common Mistakes to Avoid
- ✕Wrong parameters
- ✕Missing adjustments
Frequently Asked Questions
What does this calculator do?
Set parameters
How do I use this calculator?
Run calculation
Ready to calculate? Try the free Flash Guide Calculator
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