"Savageduck" wrote in message
news:2009062906520711272-savageduck@REMOVESPAMmecom...
On 2009-06-29 05:44:41 -0700, "whisky-dave"
said:


"Eric Stevens" wrote in message
...
On Fri, 26 Jun 2009 13:28:58 +0100, "whisky-dave"
wrote:


Yes in a manor of speaking. The new Apple iPhone, when used as a
camera
you touch the screen to select what you want the camera to focus on.

Some Nikon [e.g. D300] cameras allow you to select the point of the
image you wish to focus on.

How do they do that, or how it is achived. ?

For the iPhone I suspect there is a programmed option, how it is
implemented, I would just be guessing.

As far as the D300 and some other Nikon DSLRs go, up to 51 focus points
including 51 point 3D tracking, manually selectable using the multi
selector, single point AF, dynamic area AF, predictive focus tracking (51
pnt 3D tracking), Auto-area AF.

So you have to decide what you want in focus before taking the shot.
For me that's another thing to add to shutter delay.

If you're taking a shot and you have a cobweb in the corner of the shot
a potrait of a person wearign a hat in the centre and a UFO flying above
thier head
how would the camra know where to focus.
Easy if you have spot AF, but that makes framing difficult.
It'd be nice to be able to get home and them decide which of the 3 (in this
case)
images should be the sharp, one, two or all 3.
I guess I could always dig out my old Polaroid Land 110B with the f64 stop
pin hole,
but I don't think I can get the film, and it won't fit in my pocket like my
P&S

I'd prefer to focus after the pictures been taken, perhaps not possible yet,
but in the future I believe that it will be possible, and I don't mean by
artificially
sharpening via contrast control.


...and then there is manual focus as a final option.
Although I don't do it that much, it is/would be still my preferred method