The collimated light photometer

The errors involved in photometric measurements with the collimated light photometer are analyzed with special regard to those types of errors which are unique for this type of photometer. The most commonly found designs of light distribution photometers are described, i.e., those using an abnormal orientation of the luminaires during measurement, those with the luminaires in normal working orientation and without mirrors, those with one or more mirrors and finally some examples of short distance photometry.