On Sat, 30 Jun 2012 13:04:07 +0200, Wolfgang Weisselberg
wrote:
: Robert Coe wrote:
: On Fri, 29 Jun 2012 13:22:17 +0200, Wolfgang Weisselberg
: : Me wrote:
:
: : Not sure how the auto focus point select system works on the higher
: : end nikons. Despite 51 AF points, there's surely not enough data
: : for full face detect,
:
: : The 1DX does have a rather high resolution exposure sensor,
: : which has more than enough resolution for face detect ...
: : a fact that Canon has cleverly engineered in and uses.
:
: Isn't the crux of the matter that face detect can work only in live view mode?
:
: No.
:
: Because if the image of the subject is being deflected into the viewfinder,
: it's not available to the sensor for analysis. Which would seem to make it
: useless for AF if the camera is used for action photography.
:
: Is the exposure sensor able to get data when the mirror is down,
: and if not, how is metering done?

I believe there's a special metering sensor built into the viewfinder. But it
seems unlikely that it would have either the resolution or the computing power
to be useful for face detection. That said, I have no expertise at all in this
area; I've never had occasion to use a camera with face detection.

Bob