ISO lumens

White light output measured by the 9-point method. The screen is split into a 3×3 grid, illuminance is measured at each centre, then averaged and multiplied by image area. It's a production average, and units must reach ≥80% of it.

Unit: lm
Standard: ISO/IEC 21118:2020 + IEC 61947-1 9-point method
ISO 21118: ISO 21118 required
Better: ↑ Higher

Point 1Point 2Point 3Point 4Point 5Point 6Point 7Point 8Point 9

Image width2.00 m

Mean illuminance: 313 lux
Image area: 2.25 m²
Light output: 705 lm; mean lux × m²
Uniformity: 62 %; darkest ÷ brightest

Show the numbers

Point 1	260 lux
Point 2	340 lux
Point 3	260 lux
Point 4	340 lux
Point 5	420 lux
Point 6	340 lux
Point 7	260 lux
Point 8	340 lux
Point 9	260 lux
Lumens	705.0 lm
Uniformity	61.9 %

The 9-point method (IEC 61947-1, the basis of ISO/IEC 21118 light output and the old ANSI lumens): measure illuminance at nine points of a 3×3 grid, average them, multiply by the image area. Uniformity here is the darkest point as a percentage of the brightest. ISO 21118 states production averages, and shipped units must reach at least 80% of the stated value.

A 16:9 image 2.00 m wide (2.25 m²) is measured at nine points in a 3 by 3 grid. The readings range from 260 to 420 lux and average 313 lux, so light output is 705 lumens (mean lux times area). Uniformity, darkest over brightest point, is 62 percent. Readings are illustrative.

How to compare it

ISO light output(lm)

The only brightness figure that is comparable across brands. Prefer it when the brand states accordance with the standard.

Measured max lumens(lm)

The brightest-mode output as measured independently.

Compare with the rated value. We show the delta and spread across sources, e.g. 'Rated 3,000 ISO lm, measured 2,340 lm (−22%), 3 sources'.

Standard: 9-point (IEC 61947-1-style) by reviewer

Marketing traps

ISO light output: Measured in the brightest mode, often with a green-tinted, uncalibrated white. Calibrated D65 output is typically much lower, especially on single-chip DLP.

Across the catalogue

ISO light output

11 of 24 projectors list it

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Deep cut

ISO light output. Lumens = mean(E₁…E₉ in lux) × A(m²). Measurements are at full white after warm-up and at zoom wide. The method doesn't constrain white point, so a 9,000 K greenish white 'wins'. Our derived screen luminance is L(cd/m²) = lm × gain ÷ (π × A).

Measured max lumens. Reviewers vary in method: a lux meter at screen vs a lens meter, 1 point vs 9. Record the method and treat single-point readings as low-confidence.

Terms on this page

ISO lumens (ISO/IEC 21118)

The current international method: ISO/IEC 21118:2020 light output, measured per its Annex B, which builds on the IEC 61947-1 9-point method. It has two compliance rules. The stated value must be a production average, and shipped units must reach ≥80% of it. Results are roughly equivalent to ANSI lumens. Dangbei (Feb 2024) and Formovie (Jul 2024) committed to ISO 21118 in their settlements with Epson. XGIMI (Sept 2023) agreed to restate "consistent with industry standards". Epson's newsroom lists many more settlements (Anker, Vava, Wemax, Yaber and others). This is our headline brightness field when available. ⚖ brightness.iso_lumens ↑