Light Meters

With the invention of the in-built light meter, some photographers have laid down their hand-held meters and are opting to just point and shoot like cavemen, however they are forgetting the importance of this very versatile tool.  When on location, it is often not the most efficient use of time, fidgeting with external light meters; however in the studio it is another story.   A light meter can help you achieve the best tonal range in your photographs without having to change it with

Reflected and Incident Light

There are two ways of measuring the amount of light in a scene.  The first is measuring the amount of reflected light emanating from the subject.  This measurement is taken either from a single spot in the scene or an average metering of the reflected light of the scene.  This measurement is used a standard for the entire picture and will make calibrate the lights and darks of the image based on this standard.  Reflective light meters are the only type of metering system capable of measuring light from a distance and thus are the only type of meters built into cameras today.

The second method of measuring light is measuring the “incident” light, which is the light that is being shone on the subject.  This type of light measurement is far more accurate than measuring reflected light because incident light readings are independent of diluted light reflected off any subject which could, depending on the colour, have a higher than average level of reflectance.  For example:  A woman wearing a white t-shirt will have a greater level of reflectance than that of a woman wearing a black t-shirt.  An incident light meter will measure the light shining ON the t-shirt, not the light bouncing off it.

How it works

The average hand-held light meter is built with a plastic spherical dome placed on top of a light sensor that records the intensity of the light by calculating its proximity and its general luminescence.  These days they are built with computer chips to record the measurements taken and provide you with the measurement on a readable LCD screen.  In general, you are able to program the meter at a certain shutter speed, ISO and/or aperture size and the measurement taken indicates which f/stop or shutter speed you should use to get the correct exposure.