Robert Coe wrote:
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

100.000 Pixel-RGB

or the computing power

A DIGIC 4 just for the AF --- that used to drive whole cameras!

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.

Looking at the published data for the 1DX could have told you
all that. No claims on how good it is, though, and no claims
that Nikon didn't do it first.

-Wolfgang