It's interesting that the 60D has a dedicated autofocus button. I
didn't know that. While it's true on the 5D that moving autofocus off
the shutter button requires that you displace auto exposure lock it is
still locked by half pressing the shutter button. I've never found it
to be a problem but maybe that's because I'm usually shooting manual
mode anyhow.
Chuck Norcutt
On 6/17/2012 4:24 PM, Moose wrote:
> Chuck and Ken, thanks for the explanation about metering. ow Ken is off on
> AF. :-)
>
> On 6/17/2012 11:12 AM, Ken Norton wrote:
>> Bill, as a general rule, that is how the AF system works in a modern camera
>> with multiple focus spots. In a DSLR, the sensor, being a phase-detect has
>> a pretty good idea of which sensor position has the closest object and that
>> one becomes the active point. With a contrast-detect AF, the lens has to do
>> a quick run through from close to far and then calculates the part of the
>> image that comes into focus at the closest point. These systems are getting
>> much more complex now, but the underlying mechanism is based on this
>> concept and will also do a fall-back to this methodology when the really
>> fancy stuff fails.
>
> So with face detection is it the closest face, or the midpoint between face
> distances?
>
> Pure curiosity, as I've never used face, or smile, or open/closed eye
> detection. I suppose I should learn how to use
> that stuff - except that, by the time, if ever, I want to use it, I'll have
> forgotten. ;-)
>
> I have always used central point only AF - focus, then frame. Particularly
> nice with 60D, which has a separate AF button
> on the back, separate from metering. Push it once and frame, reframe, etc.
> for possibly several shots. You can do that
> on the 5D, but there's no dedicated button, so some other function has to be
> dropped.
>
> One Point Moose
>
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