Tek hatam 0larda olmuş. 1DX te 100,000 pixellik bir ışıkölçer var.

Bu yazı Canon professional networkten alınmıştır:
63-ZONE DUAL-LAYER METERING SENSOR
The EOS 5D Mark III features a similar metering sensor to that found in the EOS 7D – the iFCL 63-zone Dual-layer Metering Sensor – to capture perfectly exposed images time-after-time. 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 – for example, skin tones – 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 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.

Canon Professional Network - Inside the Canon EOS 5D Mark III

Bu yazıda "benzer" diyor ama aynı. Tüm olay ışıkölçer AF sistemi ile entegre çalıştığı için buna göre Mark III te ayarlamalar yapılmış olması.