[photo-3d] AF Cameras and stereo

[Michael Watters <michael.watters@xxxxxxxxx>]

I think people are dismissing AF cameras for the wrong 
reasons.  The primary concern I'm seeing voiced is that 
they might focus on different distances and thus not be 
perfectly matched.  There's three reasons I wouldn't worry 
about that:
	1)  Unless they are WAY off from each other it 
likely won't make a difference.  After all there was a 
vintage stereo (Graphlex???) that deliberatly set the 
lenses to different distances in an effort to avoid needing 
to focus.  The reality is that unless they are VERY 
differently focussed, it won't be noticable when viewed in 
stereo.
	2)  Many AF cameras (especially the little point 
and shoots) do not have infinitly adjustable focus points.  
There's a fixed set of distances they will focus to.  This 
dramatically increases the chance they WILL sync their 
focus.

	3)  If we're talking about P&S cameras, they are 
mostly wide angle, and will have great depth of field at 
any likely f-stop they're likely to be using.  This will 
make slight focus-inconsistencies even LESS noticable.

MY concern about using AF cameras:
	TIME sync!  Many of these cameras have a huge gap 
in time between when the button is pushed and the shutter 
opening.  That irks me in a flat camera (kiss action shots 
goodbye!) but in a stereo is a disaster since that time 
interval is directly dependent on the amount of time it 
takes the camera to get the focus right.  If one camera 
does it a bit quicker - there goes your sync.

Mike

-----------------------------------------
Dr. Michael Watters
Email: Michael.Watters@xxxxxxxxx
Valparaiso University