5 Types of Photometers
Difficult lighting situations and inconsistent weather often lead photographers to rely on their photometers to have accurate readings of the light measurements of their photographic subjects. But, most photographers are aware of the importance of having accurate light measurements in order to gauge exposure length, regardless of lighting conditions, making photometers a valuable tool for every photographer, from amateur to professional.
Photometers measure light intensity, illumination and light absorption. Photometers take in and average a span of light readings, to allow photographers to set their exposures for a photograph as a whole, as light radiance will vary from place, person or item even in one photographic subject. Photometers are available in a range of complexity, from the built-in meter on a camera to the multi-functional spectrophotometer, and provide a scale of light information depending on the photographer's needs.
1. Built-In Photometer
In the early days of light meter reading, the photometer was always a separate piece of equipment from the camera. However, almost all cameras now come equipped with an internal light meter. In most cases, as with taking a casual family photo or a quick snapshot, the built-in photometer, which comes standard on cameras made in the last 50 years or so, is sufficient for reading light intensity and luminescence. While many older SLR cameras require the photographer to use the built-in photometer to set an aperture for exposure, digital cameras usually take photometer readings and set apertures automatically.
2. Hand-Held Photometer
The hand-held photometer is standard equipment for most professionals. The hand-held meter can be used much like the built-in camera photometer, but it may also be used to concentrate on the light readings of particular areas of the potential photograph.
3. Spot Photometer
The photographer may take a variety of light readings from different areas ("spots") of the photographic subject and use these readings to set the camera's exposure to highlight these chosen areas. Some spot photometers are sophisticated to the degree that they offer multi-segment metering systems that can take multiple simultaneous readings of very specific areas of the subject.
4. Incident-Light Photometer
Another common type of meter for photographers is the incident-light meter. This meter can often give more truthful measurements of light by calculating not the amount of reflected light, but rather the amount of light falling on the subject, thus using "incident" light measurements. Incident-light meters can avoid potentially incorrect exposures based on subjects with unusual reflected-light readings. These photometers also can be set to take light meter readings only when set-up lights flash, allowing the photographer to gather correct light readings for the potential flash photograph, and not just the ambient light of the subject.
5. Color Photometer
Color photometers not only gauge the amount of light reflected or falling upon the subject, but also the intensity of color radiating from the subject. These meters can be helpful for photographers looking to balance color saturation and hue in their photographs by adjusting exposures according to color readings.
Regardless of the type that is used, photometers have proven to be a long-standing and invaluable resource for photographers.