Product Photography Lighting Calculator

Light setup from product type and surface material.

Subject distance (m)

Target aperture (f/)

ISO

Flash max guide number

Lighting ratio (key:fill)

Number of lights

Modifier loss (stops)

Tab to move between fields

Key light power (%)

12.1

Fill light power (%)

Required guide number12

Effective GN (at ISO)58

Ratio in stops1.58

Total power (Ws est.)27

Max f/ at distance38.7

White balance (K)5,500

Min Aperture At Full Power22.99

How to Use This Calculator

Select the product category (jewelry, apparel, electronics, food, etc.).
Enter the product dimensions (width, height, and depth in inches).
Set the background type (white seamless, colored, lifestyle).
Review the Key Light Power, Fill Ratio, and Background Light Power recommendations.
Use the Light Placement Diagram output to position modifiers at the correct angles.

How the result changes with Flash max guide number

Subject distance (m): Distance from flash to subject in meters.
Target aperture (f/): Desired f-stop for the shot (f/8-f/11 typical for products).
ISO: Camera ISO setting (100 recommended for product shots).
Flash max guide number: Maximum guide number of your flash at ISO 100 and full power.
Lighting ratio (key:fill): Key-to-fill lighting ratio (2:1 soft, 4:1 dramatic).
Number of lights: Total number of lights in the setup.
Modifier loss (stops): Light loss from softbox/umbrella/diffuser (typically 1-2 stops).

Required guide number: Guide number needed for correct exposure at set distance and aperture.
Effective GN (at ISO): Flash guide number adjusted for your ISO setting.
Key light power (%): Flash power setting for the key (main) light.
Fill light power (%): Flash power setting for the fill light.
Ratio in stops: Lighting ratio expressed as stops difference.
Total power (Ws est.): Estimated total watt-seconds consumed by all lights.
Max f/ at distance: Smallest aperture (highest f/) achievable at full power.
White balance (K): Recommended white balance for flash lighting.

Identify Input Parameters
4 parameters
Subject distance (m) = 1.5, Target aperture (f/) = 8, ISO = 100, Flash max guide number = 58 = 7 input(s) provided
Calculate Key light power
Key light power = min(
12.1 = 12.1
Calculate Fill light power
Fill light power = flashPowerPct / lightingRatio
4 = 4
Calculate Required guide number
Required guide number = subjectDistanceM * aperture
12 = 12
Calculate Effective GN
Effective GN = flashGnMax * isoFactor
58 = 58