IES LM-77-09

The intent of LM-77-09 is to describe measurement procedures for the determination of the luminous intensity distribution of certain lamps and luminaries using a digital camera to capture the projected light distribution from a luminaire on a screen. This measurement technique is relatively new, therefore considerable detail is provided to assist the reader in understanding the principles, requirements and limitations involved. Digital photometry offers very high speed data collection over a traditional goniophotometer, although typically over a restricted angular range. Many factors must be taken into account to achieve accurate digital photometry and this report addresses the most significant of these factors.