A foot candle meter is a device used to measure light in photography, film and other areas where light is a priority. Based on a standard measurement of light called a foot candle, a foot candle meter gives readings as to the amount of light at a given point. Foot candle meters are also sometimes synonymous with light meters, and may be purchased at photography or film supply stores and through online brokers.
The concept of a foot candle is somewhat difficult to explain simply, but one foot candle is essentially a measurement of the intensity of light given or emitted by a standard candle in one square foot. In metric systems, this measurement is often referred to as a lux. Most light meters are standardized as to the size and illumination of the standard candle.
A foot candle meter may be able to give one specific type of reading, or may be able to measure several different types of light. An incident foot candle meter reads how much light is falling on an object. A reflective meter can read how much light the object reflects. Some digital meters are capable of giving both readings, but may convert some measurements into other units.
When shooting photography or film, a photographer uses a foot candle meter to set exposure levels on the camera. How much light is falling on the frame, and how reflective objects are, will affect how the finished shot looks. There is no “right” exposure level for most shots, but many photographers and cinematographers pay careful attention to light levels in order to create specific looks or styles through exposure levels.
Often, multiple readings from a foot candle meter are necessary to get an idea of how a scene or frame should be lit. Most meters can only read the area directly in front of them, so an object closer to a light source may have a higher foot candle reading than one farther away. Objects also have different levels of reflectivity that may cause the meter reading to change significantly. A photographer may use many different readings to get a comprehensive idea of how to light a frame.
Other uses for a foot candle meter include architectural lighting design, where a meter can show levels of light to optimize the atmosphere of a room. Some people use foot candle meters to measure how much light is being cast on plants that are sensitive to high levels. Museums may use meters to determine the exposure of artwork to light, to ensure damage is not being caused by excess exposure.
Foot candle meters are generally small, handheld devices. Most are digital meters, but some old hands still use complicated manual versions. Meters may occasionally need to be sent to the manufacturer or a third-party company for recalibration, to ensure they are taking accurate measurements.