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View Full Version : where are d300s cross points?


reaction
13-10-2010, 5:00pm
where are d300s cross points?

I can only find there are 15cross points, but not which ones they are, what sensitivity etc. ANyone have a pic?
ricktas
13-10-2010, 5:22pm
cross points? Do you mean focus points?
ricktas
13-10-2010, 5:24pm
The D300s has 51 focus points:

http://a.img-dpreview.com/reviews/nikond300/Images/Additional/afpoints.gif

Focus Point • Single point from 51 or 11 focus points
• Liveview (Tripod mode): Contrast AF on a desired point anywhere within frame
AF Area Mode

• Single point AF
• Dynamic Area AF [9 points, 21 points, 51 points, 51 points (3D-tracking)]
• Automatic-area AF
BLWNHR
13-10-2010, 5:35pm
cross points? Do you mean focus points?

No, I'm pretty sure Reaction means cross-type AF sensors. Have a read here. (http://en.wikipedia.org/wiki/Autofocus) Specifically under the "Phase detection" heading.

Reaction, this should answer your question. The answer is on a Nikon site too, so we know it's accurate.


Moreover, it employs 15 powerful cross-type sensors in the center of the frame to give you the ultimate in detection performance with any AF NIKKOR lens of f/5.6 or faster. (http://imaging.nikon.com/products/imaging/lineup/microsite/d300s/en/speed-accuracy/)

They would be the 15 larger sensors in the image Rick posted:

http://a.img-dpreview.com/reviews/nikond300/Images/Additional/afpoints.gif
reaction
13-10-2010, 6:39pm
oh, they're all in the middle... is there a reason there are none towards the edge too? eg for vertical portraits?
BLWNHR
13-10-2010, 7:54pm
I don't know, but maybe it has something to do with the amount of space they take up for an electronic standpoint, or maybe light fall-off from vignetting effects them (after all they don't work past f/5.6.
reaction
14-10-2010, 8:22am
the non cross-types, are they vertical or horizontal, or mixed?
BLWNHR
14-10-2010, 10:09am
I can't seem to find that information.

Why is this a concern? I can tell you first hand the AF system is very very good. Even using the extreme edge focus points with a UWA lens and a very high speed subject I was able to capture things like this (http://smg.photobucket.com/albums/v197/blownhr/Photography/?action=view&current=_DSC6222.jpg) with consistantly sharp focus.
kiwi
14-10-2010, 11:47am
The D300 has the best focus point coverage in the Nikon range. The D3 has the same focus points but in FX sensor they only cover the DX crop, if you know what I mean

I never found it an issue tracking objects in the edges, quite why youd want to do that is a bit of a mystery anyhow re composition