The difference between lumens and ANSI lumens lies primarily in how light output is measured and standardized:
Lumens:
This is a general measurement of the total amount of visible light emitted by a light source. It measures the overall light output, regardless of how it is distributed or captured. Manufacturers can measure lumens without standardized methods, which may lead to variations in actual brightness between devices.
ANSI Lumens:
This is a standardized measurement defined by the American National Standards Institute (ANSI). It measures the brightness of a projector using a specific procedure, taking light output readings from various zones of a projected image and calculating the average. This method ensures a consistent and accurate comparison of brightness across different projectors.
In short, ANSI lumens provide a more reliable and standardized way to evaluate the brightness of projectors, while lumens are more general and sometimes less consistent.