T1i exposure comp?

Is it a feature? I'm not exactly sure how it works. Like, does the exposure comp. mess with the aperture/shutter speed depending on what mode I'm in, or is it kind of like ISO, which boosts the brightness of the photo? Not sure if I'm being clear, but I'm a little confused about this.

Exposure compensation adjusts the exposure up or down as much as you ask it to do. Depending on the mode and the ISO setting (manual or auto) it will adjust the 'floating' variable up and down. If you're in Tv mode and you set the shutter to 1/60th and it suggests f/4 and you suggest -1/3 exposure compensation it may adjust the aperture to f/4.5. If you suggest +1/3 it will likely adjust the aperture to f/3.5. It isn't "messing with" things, it is doing what you asked it to, it is adjusting the settings to where it would have metered if it had metered higher or lower as you've set in exposure compensation.

If auto ISO is set then it might adjust that rather than the aperture. In Av mode it will bump the shutter speed, leaving your selected aperture. In P mode it will adjust the program up or down, adjusting one or both of aperture and shutter speed and ISO if set to auto.

It is really for cases where you think the meter is wrong. The meter is expecting 18% grey so if you are metering white snow or a black tuxedo it will be 'fooled' so you'll want to adjust the exposure. Same for backlighting.

You can adjust the exposure later in post processing but it is best to get it right in camera if possible. Exposure compensation or manual mode can help you do this rather than just trusting the camera's meter.

In Av mode, it alters shutter speed; in Tv mode, it alters aperture; in M, it doesn't apply. I'm not sure offhand what happens in other modes as I don't use them.

hpulley wrote in post #9485701
It is really for cases where you think the meter is wrong. The meter is expecting 18% grey so if you are metering white snow or a black tuxedo it will be 'fooled' so you'll want to adjust the exposure. Same for backlighting.

You can adjust the exposure later in post processing but it is best to get it right in camera if possible. Exposure compensation or manual mode can help you do this rather than just trusting the camera's meter.

I don't really understand the quoted part. 18% gray? I'm a little lost. I don't really understand the basics of exposure/metering. I'm trying to get there though.

What do you mean by if I'm metering white snow or a black tuxedo? What would be the reason for metering off of that?

I just mean if you are photographing a snowy scene or a person in a black tuxedo, the meter will attempt to make both of those scenes metered correctly assuming they are grey. They will try to make the white snow and the black tux grey. Thinking about it this means the snow will look too dark and the tuxedo will look too light. If you know you are photographing snow you can use +1 stop of exposure compensation to make it look white again. The tux you can use -1 stop to make it black again. Just examples.

I think you might be another person who needs to read Understanding Exposure.

quadwing wrote in post #9485731
I don't really understand the quoted part. 18% gray? I'm a little lost. I don't really understand the basics of exposure/metering. I'm trying to get there though.

What do you mean by if I'm metering white snow or a black tuxedo? What would be the reason for metering off of that?

Read this before you do anything else (there's also lots of other good stuff on that site):
http://www.cambridgein​colour.com/tutorials/c​amera-metering.htm

Then read this:
https://photography-on-the.net/forum/showthre​ad.php?t=414088