They record each impact using high-speed cameras and light meters.

This phenomenon was used in the design of light meters and similar devices.

The camera had to be taken away from the eye view, to observe the needle on the light meter.

The most common use of such light meters is measuring the exposure value for photography.

This allows a light meter to be used to estimate an exposure.

A light meter can be used to assess the level of lighting present.

Charlie was already setting up, and Mark moved around with the light meter.

We used to have a whole drawer of light meters to give out.

PX675 type mercury batteries are only needed for the light meter.

A photographer stood by the far wall, trying to find a reading on his light meter.