metering question

[OceanRider]

Metering question

Hi all,

I am having trouble understanding when to use each metering mode on my 20D. Have read the manual but its somewhat vague.

EVALUATIVE METERING-This looks like it takes the entire picture into consideration before setting exposure.

PARTIAL METERING - Measures just the center area to obtain proper exposure.

CENTERWEIGHTED AVERAGE METERING-Weighted at center than averaged for entire scene.

Which one is the best one to have on as default?Do you really notice a difference switching them around?

Any thoughts or insight would be appreciated.

Joel:D

[donlavange]

I think the evaluative metering works well and you can see the active spot that is the focal point. For long lenses, the center is of value.

I still like to make a final manual check on the focus point by eye (if I have the time). And if I have enough light to see clearly enough.

[PacAce]

Evaluative metering places emphasis on the AF point, which the camera assumes is where the important subject is. However, it also takes into consideration the reading from the other parts of the frame and based on information of similar scenes stored in a database, an appropriate exposure setting is calclulated. Using evaluative metering, scenes like those that are backlit would give you a better picture than if the center-weighted average metering had been used. Evaluative metering only work when the camera is in AF mode. If you switch to manual focusing of the lens, the camera defaults to center-weighted average metering.

For scenes where the entire frame has equal importance with no particuclar subject, such as an ordinary landscape, or where the entire frame is filled with the subject, center-weighted average metering would give you a good exposure. But that's not to say that the other metering modes can't be used in a similar situation.

If you care more about getting the subject properly exposed without regard to the exposure of the background, then you would use partial metering with the center area over the subject. This ensures that the exposure reading is not influenced much by the background.

I don't think there is any one particular metering mode that is better or superior to the others. It all a matter of knowing how each behaves and using each to your advantage. Obviously it's going to take some time to get familiar with each of these metering modes but that will only happen if spend some time with each mode. Most people are happy just using the evaluative metering mode. Others feel more comfortable using the averaged metering because it's more predictable than evaluative.