scope:

FOREWORD

The intent of this IES document is to describe measurement procedures for the determination of the luminous intensity distribution of certain lamps and luminaires using a digital camera to capture the projected light distribution from a luminaire on a screen. Because this is a relatively new technique, considerable detail is provided to assist the reader in understanding the principles, requirements and limitations involved. As more experience is gained and as digital cameras increase in their capabilities, further requirements are likely to be developed. At this stage of development, digital photometry offers very high speed data collection versus a traditional goniophotometer, although typically over a restricted angular range. Many factors must be taken into account to achieve accurate digital photometry; this report addresses the most significant of these factors.

Other uses of cameras to perform digital photometry, such as capturing the distribution of a luminaire by aiming the camera at the luminaire, close field photometry techniques and methods using integrating spheres, are outside the scope of this report.