Use a Light Meter to Measure FC
FC (or "footcandle") is a measurement of light; 1 FC is the amount of illumination on a surface 1 foot away from a common candle. Photographers use light meters to measure the amount of illumination on their subjects so that they can calculate the proper settings to use in their cameras to capture the right exposure. While most light meters can be set to provide illuminance values in either footcandles, the light meters that are integrated into cameras often do not give this absolute value. Instead, you can manipulate the settings on your camera to use the onboard light meter to measure FC.
Instructions
1. Set your digital camera to 100 ISO. The ISO value refers to your electronic sensor's sensitivity to light; the higher the value, the more sensitive the sensor.
2. Put your camera in Shutter Priority mode. In this mode, you can manually set your shutter speed, and the camera will automatically determine an appropriate aperture.
3. Ensure that no exposure compensation is being applied to the light meter. In your display window, you should see a line graph with -2 and +2 at each extreme. This is your exposure compensation. The arrow should be in the center at 0.
4. Set your camera's shutter speed to 1/15 of a second.
5. Hold a white sheet of paper at a 45-degree angle to your subject, and at a 45-degree angle to your camera.
6. Meter on the white sheet of paper by pointing your camera toward the paper and keeping your center focus point directly over the paper. Depending on your metering mode, you may need to zoom in to fill your frame with the white sheet to get an accurate illuminance rating.
7. Observe the camera's aperture value. If your camera suggests, for example, f/2.8 as your aperture, the illuminance on your subject is 5 FC. For each stop of light upward or downward, the FC value doubles or halves. For instance, f/4 is one stop higher than f/2.8, so the illuminance value doubles to 10 FC, while f/16 is four stops higher than f/4, so the illuminance value doubles four times to 160 FC.
Tags: your camera, light meters, value doubles, white sheet, 45-degree angle, 45-degree angle your
