Thanks for the tips. Is there any difference between using EV comp and simply metering slightly left or right?
I'm assuming it merely shifts what the meter displays and doesn't adjust shutter/aperture or ISO.
What do you mean by metering slightly left or right? Are you talking about manual or AV/TV mode?
Say you are in AV mode, ISO is set at 100 and aperture f/4.0 and you are using 0 EV compensation. The camera meters the scene at 1/500th of a second.
Now, if you want to overexpose the scene by +2/3 stops you dial in +2/3 EV compensation, then the camera will give you a shutter speed 2/3rd stop slower than 1/500 i.e. 1/320th sec.
If you were in TV mode (ISO=100) and shutter speed 1/500th sec then for exactly the same scene the camera will give you f/4.0 aperture. If you again dial in +2/3 EV comp, then the camera will choose f/3.2 which is 2/3 stops larger aperture than f/4.0.
However, if you are in Manual mode, then you cannot dial in EV compensation. Take the above scene again. ISO=100, you choose aperture f/4.0, shutter speed 1/500th sec. Since that was exposure level chosen at either AV or TV mode with 0 EV compensation, therefore, the meter indicator will be in blinking at the middle of the scale. You want to overexpose the scene by +2/3 stops, then you need to either go for f/3.2 (you are on manual mode) or 1/320th sec (or 1/3rd stop larger aperture and 1/3 stop slower shutter speed or any such combination)
Bottom line is in AV/TV mode you can dial in the Exposure Compensation and camera changes the shutter speed/aperture; in Manual mode to get a higher exposure you need to choose the shutter speed or aperture or both yourself.