About Autofocus points on Rebel 2000

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I am a beginner of a photography and I have just got a Rebel 2000 w/Tamron 28-200mm AF. I have read through the manuel but I have a trouble to understand how the 7 autofocus points works.

When I try to focus a subject using the [+] at the center of the viewfinder, the autofocus points display sometimes show two points at side, sometimes four points, etc. So, what different would the focus points make?

For example, in a full auto mode, I use [+] to point at my friend's face with 28mm, 10ft away from the camera, and then press the shutter halfway, the autofocus points display shows 6 points, "-----" - (assuming "-" is the focus point on the display) However, one focus point is missing at the top which is the area of the face. If I take a picture with this setting, what happen to the exposure-- according to my understanding, I think the exposure would base on the 6 focus points, am I right?

In short, how should I focus a subject using Rebel 2000, based on the [+] on the viewfinder or based on the focus points?

Thanks, jl

-- John Lok (boolok@hotmail.com), July 05, 2000

Answers

I have EOS300 (this should be the same as Rebel 2000) and as far as I was able to determine the focus points story goes like this: in "pictogram" modes (portrait, landscape, etc.) the camera chooses whatever number and position of focus points it seems fit. In "creative" modes (P, Av, Tv, M) you can select a single focus point with the button on the left side of the display. So, you should base your focusing on the focusing points that are visible in the viewfinder.

Choosing focus points in no way, according to my expirience, affects metering system (exposure). In pictogram modes the metering system is always "matrix" (the whole area is metered and compared with patterns in camera memory). In creative modes (P, Av, Tv) matrix mettering is used as well. In M (manual) mode the "weighted average" mettering is used. As I was able to figure out, this means that metering data taken from center area is most significant, and "border" area is least significant.

In all creative modes you can use spot mettering (9.5% of the center area is metterd) if you press the "*" button.

-- Krunoslav Kovacic (k.kovacic@vipnet.hr), July 28, 2000.


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