Does the AF point affect metering?

[martcol]

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

[scottbergerphoto]

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

[martcol]

...if you point the camera and half depress the shutter button, you lock focus and exposure on what was in the viewfinder...
Thanks Scott

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

Martin

[vvizard]

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.

[martcol]

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.

Sorry to sound so dense :oops:

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

martin

[scottbergerphoto]

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.

Sorry to sound so dense :oops:

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

[jstatler]

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 :D

[rodbunn]

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

[leony]

Page 75 of 10D Manual:

Evaluative Metering
This is an all-around metering mode suited even for
backlit subjects. The viewfinder is divided into 35
metering zones to which all the AF points are linked
for evaluative metering. After detecting the main
subject’s position, brightness, background, front and
back lighting conditions, camera orientation (horizontal
or vertical), etc., the camera sets the proper exposure.
• During manual focusing, evaluative metering is
based on the center AF point.
• If the subject brightness and background light level
are very different (strong backlight or spotlight),
partial metering ( ) is recommended instead.

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

Manual available here: http://www.powershot.com/powershot2/customer/pdf/EOS_10D_E.pdf Adobe Acrobat Reader required.

[martcol]

Helpful thread

Thanks everyone

Martin

[slin100]

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.
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.

[scottbergerphoto]

Page 75 of 10D Manual:

Evaluative Metering
This is an all-around metering mode suited even for
backlit subjects. The viewfinder is divided into 35
metering zones to which all the AF points are linked
for evaluative metering. After detecting the main
subject’s position, brightness, background, front and
back lighting conditions, camera orientation (horizontal
or vertical), etc., the camera sets the proper exposure.
• During manual focusing, evaluative metering is
based on the center AF point.
• If the subject brightness and background light level
are very different (strong backlight or spotlight),
partial metering ( ) is recommended instead.

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

Manual available here: http://www.powershot.com/powershot2/customer/pdf/EOS_10D_E.pdf Adobe Acrobat Reader required.
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.