Does the AF point affect metering?

So, if I always use the centre AF point (10D), and half-press the shutter release then recompose, which I mostly/often do....

Does it have any affect on metering?

Martin

The 10D does not link metering of ambient light to the active AF point. However if you point the camera and half depress the shutter button, you lock focus and exposure on what was in the viewfinder. The exposure area will be determined by which mode your in: CW, Partial, Evaluative.
Scott

Thanks Scott

If I understand that, the exposure is set on what I focussed (1/2 press)over what I'm shooting (recompose)?

Martin

If you haven't changed things in cutom-functions (which you can by the way), you half-press the shutter to set the exposure, and autofocus. Now, if you don't release the shutter from it's half-pressed possition, you can recompose the scene, and full-press for the actual picture to be taken. Unless you use a very small f-number, be sure that the object hitting your center AF-point (if that's the point you normally use) during exposure-lock, is at the same distance as your subject will be, as the AF will get locked too, unless you're in AI servo mode.

Sorry to sound so dense

So, after half pressing the shutter release and keeping it down the exposure is set there, not on what I recompose on?

martin

Yes.
Don't feel bad. We are all learning. The exposure is locked when you half depress the shutter button, except in AI Servo. The amount of the image in the viewfinder that affects the exposure reading depends on whether you selected Evaluative, Center Weighted, or partial metering. In AI Servo, the exposure isn't locked until you fully depess the shutter.
Regards,
Scott

Try out custom function 4. It will allow you to autofocus on your AE lock button and use your shutter button for locking your exposure. Good time to use is when your subject is backlit harshly. Meter your background with your shutter button use the AElock to autofocus on subject and then shoot away. Check it out in the manual under custom functions. Good Luck

Don't forget !

That's true if you don't have a FLASH on . If you are using
flash, then whatever you "recompose" onto is going to determine
the exposure (unless you lock the flash exposure with the FEL button).


Rod

Page 75 of 10D Manual:

Given the statement in BOLD - the selected focusing point does have weight on Auto Exposure.

Manual available here: http://www.powershot.c​om …ustomer/pdf/EOS​_10D_E.pdf Adobe Acrobat Reader required.

Helpful thread

Thanks everyone

Martin

Just to clarify, this is CFn 4-1. Half pressing the shutter button will lock exposure. CFn 4-3 will not lock exposure until the shutter if fully depressed.

That implies much more influence then is the reality. Try taking a picture of someone in front of a lake or some other scene where there is a wide variation in lighting. The Evaluative metering will be thrown off by areas of brightness or darkness. It doesn't function any way near a spot linked AF point. That was what I was trying to convey. In spite of what the manual says, Evaluative Metering works best when the lighting is even.