A new instrument for measuring the underwater spectral radiance distribution is described. This instrument, the electro-optic radiance distribu-tion camera system (RADS), is based on two electro-optic charge-injection device cameras with fisheye lenses and a filter changer for selection of the spectral region of interest. RADS allows a complete spectral radiance distribution to be measured in a short period of time and allows routine reduction to absolute radiometric data. Many other apparent optical properties such as vector irradiance, scalar irradiance, average cosine, and net irradiance can be derived from these radiance data. In this paper, the instrument is described, values of other optical properties derived from the data are presented, and the inherent optical property of absorption is calculated from the radiance distributions using Gershun's law.