A light meter is an instrument that measures light from any source. There are two types of light meters available; electrical and photo-electric. An electrical light meter measures the light falling on a particular surface. Photo-electric light meters do precisely the opposite; they measure how much light is absorbed or emitted by a light source. First, let’s look at the importance of the light meters in general.
There are three light metering modes available in a digital camera; spot, point-and-shoot, and automatic. A spotlight meter determines the type of light that falls directly on the camera sensor. The mode that allows for the most flexibility is the spotlight metering mode. However, you have to manually focus each shot with this option by pushing the camera slightly towards the object you want to photograph. In other words, you cannot automatically focus as you please.
Point-and-shoot cameras allow you to make manual adjustments in various settings such as aperture, shutter speed, and flash use. You have more control over lighting in this mode and usually find it more comfortable to use. Because you can quickly increase or decrease the ISO speed and aperture, you will have greater flexibility in controlling the amount of light you want to photograph.
The final type of meter we will discuss is the reflective light metering system. It is perhaps the most widely used type of meter in photography today. It is usually attached to the camera and measures the amount of light that bounces off the camera sensor. These meters measure the amount of light that reaches the film after the sensor has captured the scene. The more bounce-off light the meter readings, the underexposed the scene. For underexposed scenes, the reflectivity meter will indicate not enough light reaching the film for the scene.
There are two types of lighting meters: physical and digital. With physical meters, you look at the face of the meter to read the measurement. With digital meters, you look at a console inside the camera or view the display on the digital meter. Digital meters are generally much easier to use than mechanical meters, and they are also more accurate.
With a light meter, you will need to determine what kind of measurement you are interested in. There are five measurements: pulse rate, total light exposure, spotlight, DFA measurement, and maximum power consumption. Depending upon your purposes, you will need to use one or all of these measurements. For example, to measure pulse rate, you will either use the monitor dial or flip through the modes on the rear panel, including Continuous shooting, Evaluate, or Foreground.
The final section of a light meter shows a summary of the readings. It includes the readings in percentages. The percentages are helpful because they give you an idea of the light meter’s ability to handle the light level needed to complete a shot. If a percentage is below 100, this means the camera may not be able to supply the light needed. If a percentage is above 100, the camera may compensate for the light by reducing the shutter speed or increasing the ISO setting.
Understanding the differences between the light meter and the camera is essential if you use a light meter or digital camera equipment for assignments requiring highly accurate measurements. First, you should become familiar with the different light meter options, including the mechanical, optical, and reflective light metering systems. Then, you can choose the system that will give you the most accurate results. With this equipment, you can produce professional-looking photos and advance your career.