brand new macbook pro built-in cam too dark?

i just received my new macbook pro, finally made the switch from windows

however, im right now at my living room which has medium-low light right now

im using photo booth, and the camera's image is kind of dark. like i almost can't see myself. if i turn up all the brightness from the screen, i can see my face but in a very ghost-like way

i just borrowed my roomate's windows laptop, opened the camera, and the difference in brightness is crazy. i can see my whole self there in an ok way, while in the isight cam of my macbook is super dark.

is this a hardware problem?

if i go to a well lit place the image of the macbook camera is fine.

but in a darkish place (though with some light source) the image is dark. and i have to turn up the main light of my living room to have a good image

is this a normal behavior for the cam?

im really worried