Luminance measurement adapter

The PL-68 adapter is an instrument that enables to measure the illuminance of the self- luminescent surfaces with the use of the luxmeter.


It is intended for co-operation with photometric probes of illuminance meters made by SONOPAN. Combined with the probe, it becomes the so-called contact luminance meter.

It is suitable for the illuminance measurement of the self-luminescent surfaces e.g. negatoscopes, diffuse surfaces of the lighting luminaries, etc. After the PL-68 adapter is placed on the probe and put onto the tested surface, the value indicated by the luxmeter in lx is the equivalent of the value of the measured luminance expressed in cd / m2.

The conditions for the correct measurement are the uniform luminous flux distribution of the surface being tested in the range of the limit measurement angle as well as the uniform luminance (brightness) of the tested field. A further condition is that the reception field of the adapter should be put to the object as it is unacceptable to conduct the measurement within any distance from it.

Combined with the luxmeter, it becomes the luminance meter which is available at a resonable price.

The PL-68 adapter has an option of adjustment, which enables the set of the adapter and luxmeter to be distinctly calibrated.


Technical data

Measurement range:
as used luxmeter in lx
Entrance pupil:
12.5 mm
Aperture angle:
Limit measurement angle:
Φ 50 x 43 mm