Originally posted by Winder All modern cameras have amazing sensors in them. Its the technology that supports that sensor that is important. AF, Pixel Shift, dual pixel AF....
Indeed.
An interesting development has been the rise of the high pixel count metering sensor in most high-horsepower new DSLR's, and their role in making the cameras perform better (eg better AF tracking based on colour information, PDAF face detection, backlight correction, stadium flickering light correction, complex flash metering, general WB refinement etc etc).
Up until quite recently the metering sensors in many DSLR's were pretty crude - eg Canon 5D3 and 7D with mere 63 zone meters in a 7x9 matrix, the D700 with mere 1k pixel RGB metering, D610/D7200 with mere 2k pixel RGB meters. Simple chips doing basic exposure and colour assessment work.
But then metering chips began to step up in complexity and power - eg the 91k RGB metering sensor in D4s/D800/810/D750, now a 180k pixel RGB sensor in D5/D500. Similarly 100k pixel RGB sensor in the 1Dx, 150k pixel RGB sensor in 7D2, now 360k pixel RGB sensor in 1DxII. Canon even devotes a separate Digic coprocessor chip just to drive the metering sensor in the 1DxII. And most of these high MP metering sensors now meter down to -3 EV or thereabouts too.
Of course the complex 86k pixel RGB metering sensor of the K-3/645Z/K-1 was a big upgrade to the old 77 segment meter in K-7/K-5, and it has been asked to do more than the K-5 meter was ever asked to do too - scene recognition, subject colour tracking, AF assist etc, not just correctly meter the scene.
A new element of the camera arms race. 1 MP+ RGB metering sensors will probably be common soon.