Light Metering Help - Canon 500D

[RobbieG]

Can someone please help me understand how the light meter works in my Canon 500D?

With my Metering Mode set to evaluative, if I change my AF point from automatic to the center point and focus on something, it appears to only meter the light for that point only leaving an overexposed shot if that focal point happens to be in the shade.

Does the camera only meter on the focus points as it appears to, and if so, is this not the same as spot metering?

What I am trying to achieve is to focus on a particular spot but have the whole frame evaluated for light as is my understanding of how evaluative light metering should work. However, if my subject happens to be slightly shaded, the rest of the shot seems to be totally overexposed.

The example pic I have attached is a disappointing shot being overexposed with the waterfall falling in the shade. This shot was taken in Program mode, ISO100 with evaluative metering and the center AF point selected. The camera selected 1/60 f5.0 overexposing the shot.

Some further experiments only seem to support my thoughts.
Example-1 was taken in Program mode ISO100 with evaluative metering. The center AF point was selected and I focused on the bright area of the lawn. The camera selected 1/100 f5.0.
Example-2 was essentially the same shot with the same settings however this time I focused on the palm frond next to the bright area of the lawn and the camera selected 1/60 f4.0 which overexposes the lawn.

When I experiment and set the AF to automatic, it is a bit hit and miss with what points are used for focus, not guaranteeing the center point but seemingly metering for the points that achieved focus.

I am a new DSLR user and am disappointed with my new camera. My G9 seems to do a better job metering so I am hopeful it is just a combination of settings I have got wrong.

Thanks in advance
Robbie

[i speak in math]

"other" would be the right sub-forum for this question as it deals with exposure and not lighting but we can still try to help you. Not everyone looks in here.

Are you really changing the auto focus mode from all points to center point or is that the metering mode? Auto focus usually has full auto (where the camera chooses from all points), a mode where you select the auto focus point, and center point only. Metering usually has matrix mode (where it uses the whole scene to decide exposure details), center weighted (where the center is mode important but stuff outside the center is used too) and spot metering (only the center point is used to meter). And to make it more confusing, you can mix and match for a total of 9 combinations of focus/metering combos. I would take a look at the manual and make sure you are changing what you think you are changing.

[RobbieG]

Thanks for your reply,
This is my first post so I wasn't sure exactly where things should go. I will try and move this to "other".
It is definitely the AF point that I am changing. I have read the manual from cover to cover and this is not clear hence the question on here.
With AF, it can be set to "auto" which will allow the camera to select a combination of any or all of the 9 focal points or this can be set manually to either of the 9 points individually. The metering is separate and can be either evaluative/partial/spot/center weighted.
It is when I use evaluative metering and use the center point to focus that I have problems.