From lumens to foot-lamberts
fL = lumens × share of frame on screen × gain ÷ screen area (sq ft)
Cinema reference brightness is roughly 14–16 fL in a dark theatre. A simulator room with some light benefits from 30 fL or more.
| Screen | 3,500 lm (16:9) | 5,000 lm (16:9) | 6,000 lm (16:10) |
|---|---|---|---|
| 10.5 × 8 ft (4:3) | 31 fL | 45 fL | 60 fL |
| 12 × 9 ft (4:3) | 24 fL | 35 fL | 46 fL |
| 8 × 8 ft (1:1) | 31 fL | 44 fL | 59 fL |
FOREference calculationShare of frame: 16:9 on 4:3 = 75%, on 1:1 = 56%; 16:10 on 4:3 = 83%, on 1:1 = 63%. Gain 1.0. Real output is lower in eco modes and as the light source ages.
Targets by room
| Room | Target |
|---|---|
| Blacked-out basement | 20 fL and up |
| Dim room, lights off | 30 fL and up |
| Garage with some daylight | 45–50 fL and up |
Try your own numbers in the brightness calculator, or browse the brightest projectors.
Figures marked as FOREference calculations show their working; product figures come from the sources on each product page. How we work