Calculate the exact fill light setting needed to achieve any lighting ratio — from flat editorial to dramatic fashion. Works in f-stops, watt-seconds, or percentage power on your strobe.
Select target lighting ratio
2:1
1 stop
Beauty / editorial
3:1
1.6 stops
Standard portrait
4:1
2 stops
Classic / dramatic
8:1
3 stops
High contrast fashion
Enter 5 for a 5:1 ratio
Key light setting
Used when Ws or % mode selected
Lighting setup
Please check your inputs.
Fill light aperture
f/5.6
Key light
f/8
500 Ws / full power
Fill light
f/5.6
125 Ws / 1/4 power
Lighting diagram — top down view
Lighting ratio reference — aperture ladder at your key setting
RatioFill f-stopStops diffTypical use
Target ratio
Key light
Fill light needed
Stop difference
Formula
Key position
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