How many lumens does a projector need? Distance and ambient light matter!

projector brightness is related to the ambient light and throw distance

Knowing about Throw Distance and Ambient Lighting

Typically expressed in lumens or ANSI lumens, the brightness specification is an important reference point when selecting a projector. However, the practical meaning of projector brightness and how to choose a projector for your specific installation needs can be confusing. The following information will help you understand the relationship between brightness and projection outcomes, as well as the application of brightness in projector technology.

To illustrate this complicated idea clearly, let’s compare projection brightness to the lumen ratings of automobile headlights and consider the viewing effect in different ambient lighting situations. When a car is in dark environments, you can observe its luminous intensity immediately when you turn on the headlights. On the other hand, when it is midday with strong sunlight, it’s very hard to perceive headlight brightness even when high beams on the highest lumen output are used. The same relationship exists between projector brightness and ambient lighting.

If you need ambient lighting when using the projector, then a model with higher lumens will produce better results.

If you’d like to watch movies using a projector on a 100”~120” screen without ambient lighting, around 2,000 lumens of projection brightness is ideal. If you need to turn on ambient lighting or if there are bright light sources in the room, a projector with 3,000 lumens or more will display clear images.

What about Brightness for Outdoors Projectors?

Good outdoor projectors like the BenQ GS50 deliver 500 lumens, which looks great in low light conditions and even reasonably well in well-lit indoor (also depends on image size). For outdoors usage, make sure you get a portable projector with those 500 lumens at least. Cheap portables may offer 200-300 lumens, but that won't do even at night. Sure, portable projectors aren't designed for grand cinematic experiences, so they don't need thousands of lumens, but we'd put the entry point at 500.

Do High Lumens Equal Excellent Viewing Quality? Not Necessarily.

Based on the information above, you may wonder if a model with higher brightness can be applied to various projection sizes and ambient lighting requirements while guaranteeing clear images with excellent color. Not necessarily. For home theater systems, we recommend that consumers choose a projector with appropriate brightness to show the clearest images with the best color performance and contrast ratio effect.

The light processing components of a projector consist of the projection lamp, which determines the highest brightness output, and color wheel, which controls color performance. Theoretically, a higher wattage lamp can produce a brighter image while the color wheel’s RGB purity must be controlled in order to reproduce colors accurately. Light transmission, and therefore brightness, will be compromised when it is necessary to meet pure color requirements. So instead of pursuing high lumens, projection brightness must be controlled within an appropriate range to increase color accuracy.

Please refer to CinematicColor™ for Colors as Directors Envisioned for detailed information on projector color performance.

Determine the Ideal Projector Brightness for Your Needs

When selecting a projector, there are many specifications to consider. Among them, one of the most critical specifications is brightness. Only with appropriate lumens for the throw distance and ambient lighting in your situation can the projector produce spectacularly clear images with true colors. This is particularly crucial for consumers choosing home theater systems. Before selecting the projector, you first need to determine the distance between the projector and screen, the expected picture size, and whether you’ll need lights turned on when watching movies. These criteria are very helpful when choosing projectors, so you can ensure the most enjoyable viewing experience for your family with the ideal home theater system.

Why Brightness or Lumens Matters to Projectors? [Updated 2021]