"exposure" vs "brightness"

[david_winters]

What is the happening to the image when each of these values is adjusted in RA?

Thanks

 

[David Rasberry]

Exposure adjusts the relative level of each pixel value up or down uniformly whether it is highlight, midrange or shadow, as you increase or decrease ISO speed.
Brightness adjusts black level in video terms, raising dark values in a scene first, but with minimal effect on highlights. Boosting this will reduce the value range between highlight and shadow areas.
Contrast adjusts white levels affecting the brighter values in a scene first. Boosting this increases the value range between highlight and shadow or darker areas of the image.