LanguagesExposure settings: iFCL metering
The EOS 7D SLR features an iFCL 63-zone Dual-layer Metering Sensor. The ‘FCL’ stands for ‘Focus, Colour and Luminance’ and hints at the fact that the metering system not only measures colour and luminance data, but also analyses the data provided by each point of the AF system.
The metering sensor has 63 measurement zones and is a Dual-layer design with each layer sensitive to different wavelengths of light. Electronic sensors in general are more sensitive to red light. This means when photographing subjects with lots of red in them – skin tones for example – the sensor receives a stronger signal as it only detects brightness levels. This can lead to the wrong assumption that there is more light than there really is.
The EOS 7D’s 63-zone Dual-layer Metering Sensor.
The Dual-layer system overcomes this by having one layer sensitive to red/green light and one layer sensitive to blue/green light. Both these layers measure the light in their respective spectra and the metering algorithm then combines the two to provide an accurate light reading. In this way, accurate exposures can be attained in a wide range of shooting situations and irrespective of the colour of the subject being metered.
Metering algorithm
To work with the iFCL metering sensor, the EOS 7D also features a specific metering algorithm. The EOS 7D always measures focus with all AF points regardless of the selected AF mode. During the exposure reading the EOS 7D looks to see which points, in addition to the selected point, have achieved or almost achieved focus. This information lets the camera know which part of the image is the subject. It then takes metering readings from the zones corresponding to the AF points that have achieved (or almost achieved) focus and combines them with readings from all the other zones. This allows for consistent shot-to-shot exposure, even in complex situations – for example, where there are reflections from a model’s glasses.
