Seems to me the most consistent spoiler of AF is lack of contrast,
and that would hold in dim light. But however, that doesn't go far
in explaining the f/5.6 or f/8 limits, although I do like the
geometry explanation.
Ken
At 05:14 PM 3/7/2006, you wrote:
> High-end Canon bodies have center-point AF which work at f/8
> instead of the usual f/5.6, at the expense of being bit less
> accurate.
What is it that stops the AF working past a certain aperture? It
doesn't seem like it should be light levels because there is more to
that than just aperture: A very bright room at f/6.3 would still be
easy enough to focus in, whereas a camera can really struggle to focus
in dim light at f/1.8. What gives?
David
*
***
Ken Durling
Composition and Music Services
Berkeley, CA
[510] 843-4419
*
****
*******
***********************************************************
* For list instructions, including unsubscribe, see:
* http://www.a1.nl/phomepag/markerink/eos_list.htm
***********************************************************
