Practically speaking you might say that 200 feet, for some lenses, is as close to representing infinity for whatever effect you're looking for, and maybe 500 feet for other lenses will easily pass for that widely accepted misnomer - the 'infinity' setting.
In the strictest sense, "Halfway between 10.6 meters and infinity" is a statement without meaning.
From a practical standpoint, you might say 'halfway between 10.6 meters and 150 meters' because number one, you'll have a measurable distance instead of an imaginary number (woops!) and either way, there's no way you could set your camera lens as precisely as that careful operation might suggest, even if you DID choose some actual distance as "halfway."
Too many imperfections in the chain of elements.
Just a few thoughts to muddy the waters... (and keep the thread alive?)
All the end point of this discussion will provide us will be to end up with a setting that eases our mind, not one makes better pictures. For most of us, that is... <smile>
keith whaley
Jens Bladt wrote:
Sorry - Error. It should have been: 10.6 - 5.3 = 5.3 is less than 1/3 of the distance between 10.6 and infinity :-)
Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt
-----Oprindelig meddelelse----- Fra: Jens Bladt [mailto:[EMAIL PROTECTED] Sendt: 10. april 2004 08:56 Til: [EMAIL PROTECTED] Emne: SV: Zone Focus - what is it?
...Well 29 meters are sertainly much less than 1/3 of distance to infinity, isn't it ? :-)
Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt
-----Oprindelig meddelelse----- Fra: William Robb [mailto:[EMAIL PROTECTED] Sendt: 9. april 2004 20:27 Til: [EMAIL PROTECTED] Emne: Re: Zone Focus - what is it?
----- Original Message ----- From: Subject: Re: Zone Focus - what is it?
I wish you could put that in inches and feet then I *might* get it.
It's one
of the things I never quite *got* in the photography classes I
took. (And not
getting still shows up sometimes in my landscape shots.) I've sort
of been
going with the "focus 1/3 of the way into the scene" bit.
Works sometimes, others, it doesn't.
What really stumps me is when I want something close-up in focus
and also
want infinity in focus. I don't think it's always possible, but it
does seem to
be possible sometimes. I think it depends a great deal on the lens
(mm -- what
it can focus on), but it also seems to depend on *where* you focus.
(I.E. A
landscape shot framed by fairly close-up a tree or a tree branch.)
Give or take a bit, 300mm = 1 foot. Not exact, but probably close enough for DOF calculations in landscape photography.
Didn't you buy a Canon SLR? Do they still have the depth of field program mode built in?
William Robb
