Can someone explain Exposure Compensation?

[TMR Design]

I have a limited understanding of what Exposure Compensation is but I would like to have it better explained.

I have used it and been able to use it to achieve correct (or should I say better) exposures but I don't really understand exactly what it is, how and when to use it.

[RossW]

Fundamentally, it lets you tell the camera to ignore it's first instinct about what the correct exposure should be, and either under- or over-expose by some amount.

Practical example: you want to take a picture of the moon; as you have framed it, the moon is a relatively small portion of the picture. The camera will see all of the dark sky, and think it needs to take a really long exposure to get enough light to the sensor -- because it doesn't realize that the sky is supposed to be black in this picture. The resulting image has a totally blown-out moon against a grainy grey sky.

By using EC, you tell the camera that "underexposing" by a stop or two is perfectly OK in this case, and you get a nicely exposed moon against a black sky. Similar example in the opposite direction is a back-lit person against a bright sky. Use EC to tell camera to "overexpose" so that sky is too bright, but person's face is now correct.

[Darknight]

Thank you. That helps alot... it also explains why my air show photos were so dark (i.e. my post in Misunderstanding Exposure Settings thread).

I love POTN!!

Dark

[TMR Design]

Thanks Ross. That does help. So when I am looking at the LCD and I see the exposure changing as I move the EC + or - is that an accurate (well, as accurate as you can be using an LCD display) representation of the change, or are we seeing an incorrect representation?

[Jon]

It's showing, as closely as it can, what settings will be used for your shot. Within about 1/3-1/2 stop.