This paper presents a novel method for studying threshold levels for positive phototaxis ofinsects and smaller mobile organisms. Outdoor lighting affects light sensitive species and thereis a need to evaluate the effect of light levels, spectral composition of the light and lightdistribution to mitigate the ecological impacts of the artificial light. For this purpose, a test boxinvestigating the effect of light on insects in a controlled manner has been constructed. The boxis equipped with a luminance source and the light levels can be varied from a maximum valuecontinuously down to zero. The spectral composition of the light can be varied by changing thelamp or using optical filters. For visibility of the insects the box has infrared light emitting diodesin the ceiling and two wide-angle cameras monitor the light response. The functionality of thebox is tested with the species greater wax moth.