How "Multi-segment Focusing" works

[weishengg]

Hi all,

I'm a newbie here, currently using a Sony Alpha A100, but I thought this question applies to all cameras so thats why I'm posting it in this sub-forum.

Just wondering, how do DSLRs' multipoint focus work?
Some have 9point AF, 11point AF, and all that weird weird jargons that dont really matter to me... How does the camera eventually determine which point on the frame it would focus on?

Is it by proximity? Best contrast? random? colour?

Of course I understand that it differs manufacturer to manufacturer, but just want to get a geez of the idea of autofocusing.


Thank you all very much,
WeiSheng

 

[Rashkae]

Google is your friend:

http://electronics.howstuffworks.com/autofocus9.htm

http://www.dpchallenge.com/forum.php?action=read&FORUM_THREAD_ID=244804

http://www.edn.com/index.asp?layout=blogPreview&blog_id=980000298&blog_post_id=70019607

http://answers.yahoo.com/question/index?qid=20070626140842AAS2Bmx&show=7

http://www.thephotoforum.com/forum/archive/index.php/t-824.html

 

[weishengg]

Yeah got it, thanks a lot!

Apologies for posting the question before searching on the net, slipped my mind.

Thread Closed.