[Guest]

[quote name='photonius' timestamp='1347473785' post='20067']

Hmm, so why does a camera with a fixed mirror (for permanent Phase detect AF) need phase detect points (pixels) on the sensor, if I understand that AF system correctly? Perhaps locations not covered by normal PDAF?

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Ok, more "info" about this from Sony ...

The AF-D focus mode utilizing the much written about 102 extra PD focus points on the sensor. Essentially there are two almost rectangular groups of AF sensors on each side of the central AF point. The way Sony people described this focus mode, it should be much better at tracking moving subjects by giving the camera an almost 3D sense of the subject. "Depth mapping" was a experssion they used. This actually sound a lot like the "3D focusing mode" Nikon employs and the similar technology Canon uses. The difference being Sony is using on sensor PDAF to assist the traditional AF sensors, while Canon and Nikon utilizes color and light information from their (fairly high res) exposure sensors. This basically is a vaguely "content aware" focusing system, a bit related to face detection and similar, but faster and more geard towards fast tracking of erratically moving subjects.