Digital Imaging Products And Luminance Meters: A Bright Idea

By Author: K. Leeds
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What is luminance?

Luminance is the measure of a given object or surface’s luminosity (or illuminance). It is crucial to keep in mind that luminance, and illuminance are NOT the same thing. Luminance meters gather information on the brightness or intensity of light being reflected off of a given surface. Illuminance meters measure the brightness or intensity of light striking a given surface, or “incident light” for this reason, illuminance meters are sometimes also called “incident meters.” Luminance is measured from an area to one specific point (typically this is your eye or camera lens), while luminosity is measured from a specific point to an area over a distance, the terminal distance can be millimeters, centimeters, or even meters squared. For purposes of practicality, let’s imagine luminance as a cone where the base is affixed to the source and the point is the part being measured. Illuminance, then, is the exact opposite; the point of the cone is affixed to the source, and the base being measured. Here’s an easy way to remember it: Luminance is the measure of light LEAVING ...
... the surface or object. ILuminance is the measure of the Incident Light. This being said, for best results, a luminance meter, as well as illuminance meters are welcome additions to your other digital imaging products.

Why is it important?

Knowing the amount of light coming from, or heading towards your subject is paramount if your end result is going to be top quality. Luminance meters and illuminance meters have different functions, but both are a fundamental tool to be used with the rest of your digital imaging products. If you’ve ever experienced lens flare, (or even wanted to create one) the best thing you can do, as with anything, is make sure you’re informed. Informed about what? The amount of light you have versus the amount of light you need.

What types of luminance meters are available?

There are a lot of luminance meters available out there. Most companies make everything from a nearly disposable, inexpensive luminance meter for the hobbyist who picks up a camera every once in a great while, to superb quality, high-end luminance meters for people who surround themselves with digital imaging products. The LS-110 handheld, for instance, is a great, handy little luminance meter. It runs off a 9 volt battery for easy portability. The measured luminance value is shown on an LCD screen, and a viewfinder. This means you can control the measured object without moving the instrument away from your eye. It can measure even extremely dark surfaces since its range starts at 0.001cd/m2 (that’s one one-thousandth of a candela per meter squared). It can also connect to a PC or laptop to send measurement data and receive control signals. The TL-1 illuminance meters are available in two types. One measures in foot-candles, and the other in lux. These are great, lightweight, hand-held illuminance meters for everything from indoor shots to family photos in the park.

Important note:

Light is a crucial part of any imaging task. Whether you’re trying to reduce the amount of ambient light, or over-saturate your subject, luminance meters and illuminance meters are a basic and necessary tool that will save you hours of playing with the lighting, adjusting it, and reshooting. Remember that one is a measure of light emitted from a source as it makes its way to the subject (Luminosity, or Illuminance) and the other is a measure of light being reflected off the subject afterward (Luminance).

K. Leeds is a freelance writer for Konica- Minolta, one of the leading providers of digital imaging products and light meters. Visit their website to learn more about illuminance meters at Konicaminolta.us.