Goniophotometer Selection Guide

Definition & Scope

A goniophotometer measures luminous intensity distribution of lamps or luminaires over solid angle. Typical outputs include intensity distribution curves, total luminous flux, UGR, and photometric files (IES, LDT, GLDF, SPDX) for tools such as Dialux and Relux. Selection should weigh moving-mirror (stationary sample) vs. rotating-luminaire designs, dark-room constraints, sample size, angular resolution, and standards such as IES LM-79.

FAQ

Goniophotometer vs integrating sphere — what is the difference?

Integrating spheres excel at total flux and spectral/colorimetry. Goniophotometers measure spatial intensity and produce photometric files. Type tests often need both: sphere for flux/color, gonio for distribution and glare-related metrics.

Why prefer moving-mirror goniophotometers for LM-79?

LM-79-style tests need the luminaire burning in its rated orientation. Moving-mirror designs keep the sample stationary, reducing thermal/optical drift from rotation and improving repeatability.

Which export formats matter when selecting?

Require at least IES (LM-63) and LDT (EULUMDAT). For newer design workflows, also verify GLDF and SPDX export and put them in the acceptance checklist.

Which Yiming goniophotometers are typical picks?

GMS-5000 for full-space moving-mirror work; GMS-1920/1680/1280 for horizontal benches; GMS-136 for small LED samples; GMS-2000S for VAD coverage-volume testing.