ANSI Lumens vs Lumens : How to Convert Brightness

“Wait…this projector says its brightness is 1,200 lumens, while that smaller projector says its brightness is 3,000 lumens, and is also cheaper? That doesn’t seem right, what information am I missing?”

Customers purchasing their first projector generally seek to acquire the brightest projector within their spending range. However, there is an inconsistency within the market on how brightness is measured, so how do we make sense of the various brightness specifications? This issue is a result of the fact that some brands on the market choose not to use the internationally recognized brightness standard adopted by the majority of brands, ANSI brightness, but instead advertise brightness specs in different ways. The most common are: ANSI brightness, LED brightness, and light source brightness. 

In this article, we’ll break down what each of these brightness terms really means, and why they can lead to such confusing comparisons.

While each of these three methods uses the word "lumens" to describe a given level of brightness, each method measures and defines a "lumen" quite differently. The differences in their definitions cause their values to fluctuate wildly. This can lead to cases where a projector might list a brightness value of 1,000 ANSI lumens, while an equivalent competing model might list their lumens as 2,400 because it uses an LED light source. The question then is: if all of these types of brightness are measured in lumens, why are their values so drastically different?

Suffice it to say that the reason for this inconsistency is because each of the three types of measurement options measures different aspects of a projector’s brightness. For a quick summary of these differences, see the table below:

1,000 LED lumens converts to 417 ANSI lumens (LED lumen value ÷ 2.4 = ANSI lumens; the conversion rate is based on the manufacture’s publicly disclosed numbers).

1,000 light source lumens converts to 60 ANSI lumens (Light source lumen value x 0.04 to 0.06; the exact conversion rate depends on the efficiency of the projector’s LCD panel for each manufacture).

A quick way to convert the values of one type of brightness to another can be seen below:

Convert LED Lumen to ANSI Lumen

Convert Light Source Lumen to ANSI Lumen

*In general, a portion of the brands that use LED brightness publicize an increase over ANSI brightness by a factor of 2.4 for LED brightness, but these numbers are speculations based on the most ideal lighting conditions (such as in a dark room).

*The light source brightness for a normal projector with the best optics and light conversion (the amount of light available after processing by the color wheel, mirrors, and lenses) at most is roughly 16 times the ANSI brightness.

Analyzing the tables, one might notice the only constant between them: ANSI brightness. The reason for this is because of how each brightness measure is defined.

Based on these definitions, the reason why ANSI brightness acts as the standard for measuring brightness (as shown in the tables above) becomes more apparent. ANSI brightness, as indicated in its name, is the only brightness measure which uses a standard, scientific methodology certified by an international body. This gives ANSI brightness measures a reliability that is not present in other brightness measures.

Other brightness measures may rely on arbitrary factors (as in how the HK effect is measured for LED brightness) or present an indirect brightness value (as in how light source brightness omits the negative effects a projector’s internal components has on its end brightness) to produce misleading/inflated numbers.