Light Falloff Calculator — Intensity Across a Scene

Due to the inverse square law, objects further from the light receive less illumination. In a scene 2m deep with the light at 2m, the back (4m away) receives only 25% of the front illumination — a 2-stop difference. This is why groups and products can have uneven lighting.

Move the light further from the scene. At 2m with 2m scene depth, falloff is 2 stops. At 6m with the same 2m depth it eases to about 0.8 stops, and you need to be roughly 10-11m back to get under 0.5 stops for a 2m-deep scene. The trade-off is you need much more flash power at greater distances. Alternatively, use multiple lights or reflectors to fill the back.

Yes. Deliberate falloff creates depth and drama. Placing a light close to a subject creates rapid falloff, darkening the background naturally. This is the basis of many moody portrait and food photography lighting setups. The key is controlling falloff rather than fighting it.

For even illumination across a group, the further back the light, the flatter the falloff. For a 2m-deep group, placing the light at 6-8m already gives a fairly even 0.6-0.8 stops. To get under 0.5 stops you need the light at about 5 times the group depth, roughly 10m for a 2m-deep group. Use large modifiers to keep the light soft at these distances.