A lot of other factors to consider as well especially as to which metering mode you are using. However if you are using the matrix metering where the average of the entire frame is calculated then its safe to say that your exposure is "correct" when the indicator is at the centre.
in manual mode u decide for the exposure..the camera meters the scene and gives an indication by means of the markers..if u shoot wif the marker at the centre..it only means correct exposure for the scene as what the camera thinks..this return value oso varies with different metering modes(center weight/spot/evaluative)..the good thing abt manual mode is, although the scene is metered, but u still have the flexibility to try different values..its like exposure compensation..
If it's in the centre, it means the meter tells you that is the metered reading. It might not be the reading which you want to take a photo depending on where you are metering (which scene) and also in which metering mode.
In night scenes, I tend to under-expose the scene by about 1 stop when I spot meter a subject I wish to shoot, this normally gives me a good image. But again, this varies. So try it out and understand your camera.
Keep in mind that all camera meter interpret a scene/object as 18% gray. To illustrate, if you are taking pictures of a snowfield and shoot according to your camera meter reading, you will get gray snow instead of white. You will need to compensate for the difference in exposure.
Today I went snapping pics at Raffles city they had this Barbie show going on.
Set my ISO speed high so that I need not fire my flash.
Fix my aperture and play with the the shutter speed to about 1/200 constant becos the performer moves around often.
Check picture taken vs the exposure meter found out that pictures taken at center may not be what end effect u want.
However the stage lights keep changing and I had to tune the shutter speed to suit the lighting e.g. bright to use faster shutter speed
Any easier way to do this?
if you don't understand what is tonal (18% gray, mid tone, highlight, shadow...blar blar blar) and how exposure metering (spot, average, center weighted, matrix) work and what area to take meter reading from, whatever exposure mode (A, S, P, M mode) you use is kind of blind shots.