Myth Buster: Phase Detection AF without a mirror?

Started Jul 21, 2010 | Discussions thread
Joe0Bloggs
Veteran MemberPosts: 5,391
Like?
few tens of thousands for one AF point??
In reply to Joseph S Wisniewski, Aug 27, 2010

But the new Fuji camera only gives you one center AF point for the few 10s of thousands of AF points...???

Joseph S Wisniewski wrote:

Maxime B wrote:

There's "a few 10 of thousands" of them according to Fuji.

http://translate.google.com/translate?js=y&prev=_t&hl=fr&ie=UTF-8&layout=1&eotf=1&u=http%3A%2F%2Fwww.lemondedelaphoto.com%2FFujifilm-FinePix-F300EXR-precision%2C4813.html&sl=auto&tl=en

Thank you for that link.

That's what I've been saying for over 7 years, you need 10s of thousands of pixels devoted to that function.

http://forums.dpreview.com/forums/read.asp?forum=1000&message=35851187

I thought 1/256 of the pixels seemed reasonable

Joseph S Wisniewski wrote:

tko wrote:

If you have a 10 million pixels or so, having a few, even 30 or so, mapped out is pretty much undetectable. Most people have many dead pixels, as long as they are mapped they don't even know.

Yup.

And this would be a little easier, because the pixels could be chosen to be easier to map around, i.e. all green, and not in clumps. Nothing worse to map out than a clump of 9 that happens to have red or blue on all four corners.

But it wouldn't be 30 pixels. You need about 128 per AF zone, two parallel lines of 64, or an interdigitated line of 128 with every other pixel oriented in the opposite direction. Add another line of 128 if you want that AF zone to be a cross. By the time you throw in a decent number of AF zones, you've killed 12-25,000 pixels.

Still 0.1-0.2% of a 10mp sensor. With good software, you'd never notice it.

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Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

-- hide signature --

Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

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