The exposure evaluation you get before actually taking the picture is depending on the metering mode, showing +
- 2 EV in 1/3 steps. The metering requires you to half press the shutter. There are 3 different evaluation modes in G2 (same with S30/S40), and these are:
Evaluative mode:
Using exposure data from the whole picture to calculate the EV. Pictures taken in this mode, should not experience over exponation if the EV shows 0 or less. But in my experience (with the S40), this is not always the case.
Center weighted:
Using exposure data from the whole picture, but with more weight on the center part. This mode can be set so that it follows the actual focus area. Over exponation can occur outside the weighted area, even if EV is showing 0 or less.
Spot:
Using exposure data only from a small area in the middle of the picture. Using this mode and pointing at the brightest areas of the scene, over exponation hardly occurs. Pointing at a darker spot will certainly cause over exponation. The EV always show 0 when using this mode.
All comments to the modes is assuming that you have an initial exposure compensation of 0.
The histogram on the G2, S30, S40 etc.:
You need to take the picture in order to see this histogram. This is good for checking the dynamic range of the picture, as well as detecting over exponation. Now, if this could be shown in real time (before actually taking the picture), it would be helpful!
I am a bit new to the camera, 3 months.
As far as i know if you half press the button you could see if you
are underexposing or overexposing with the small number that apears
in the left of the lcd. It marks 0 if it is OK and it goes on 1/4
EV stops.
Is not so different than my N6006 I had to half press to make the
measure. Then I had to change speed or exposure.
Please explain me...
Alvaro