F value for the autofocus sensor?!

bc_the_path · 06-16-2008, 11:34 AM

I have just read an ad (in Turkish) that provided some information on the specifications of Sony Alpha 700 camera. There, I did not quite understand this:
"An f2.8 AF sensor for high definition focusing". What does it exactly mean? Do the AF sensors really have F values? Should I understand this as "best AF performance is for lenses with an F value of 2.8"?

OniFactor · 06-16-2008, 11:54 AM

yes. if you were to use a f/1.4 lens, it would focus with no more ease than an f/2.8 lens, with a 2.8 AF sensor. most center AF spots are about 2.8, with periphery ones being f/4 or slower

06-16-2008, 11:34 AM	#1
bc_the_path Veteran Member Join Date: Mar 2007 Location: Ankara, Turkey Photos: Gallery Posts: 401	F value for the autofocus sensor?! I have just read an ad (in Turkish) that provided some information on the specifications of Sony Alpha 700 camera. There, I did not quite understand this: "An f2.8 AF sensor for high definition focusing". What does it exactly mean? Do the AF sensors really have F values? Should I understand this as "best AF performance is for lenses with an F value of 2.8"?

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06-16-2008, 11:54 AM	#2
OniFactor Veteran Member Join Date: Nov 2007 Location: Binghamton, NY, USA Posts: 643	yes. if you were to use a f/1.4 lens, it would focus with no more ease than an f/2.8 lens, with a 2.8 AF sensor. most center AF spots are about 2.8, with periphery ones being f/4 or slower