Flash Contribution Calculator
Compute flash contribution (%) either from your meter's aperture readouts (e.g., 2.8 9 or 3.5 3) or directly from a ΔEV value. Formula: % = (1 − 2−ΔEV) × 100
Input
Tip: Format is aperture and optional tenths separated by a space. For example, your Sekonic "F 2.8 9" means f/2.8 plus 0.9 stops toward the next full stop (≈ f/3.2).
Result
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Enter meter readings or ΔEV value to compute flash %