Originally posted by OregonJim Put another way:
EV is an absolute value representing the amount of light reflected by a given scene.
EC is a settable value that lets you tell the camera to expose over or under the measured EV.
In other words "exposure compensation" (EC) is accomplished by manipulating "exposure values" (EV) as expressed in EV units.
The term "exposure compensation" seems to me to be an over-inflated term that any photographer does intuitively in the normal course of taking photos.
For instance I use five different fixed aperture lens' f/5, 6.2, 7.0, 8.3 and f/12 in AV mode. Not a one of them gives me a "normal" exposure if set to a EV value of 0. All of them must be calibrated to the camera's exposure system by using an EV value of something other than an EV of 0. For instance one must be set to an EV value of -1 and another to an EV value of +.7. It never occurred to me that I was performing "exposure compensation". BTW EV values can be set on my 1958 Rollie.
Wikipedia says it well:
"In photography, some cameras include exposure compensation as a feature to allow the user to adjust the automatically calculated exposure. Compensation can be either positive (additional exposure) or negative (reduced exposure), and is commonly available in third- or half-step[1] increments, usually up to two or three steps in either direction; some digital cameras allow a greater range. Camera exposure compensation is commonly stated in terms of exposure value (EV); 1 EV is equal to one exposure step."
Interestingly the term "exposure compensation" is never used in the K20D manual except in reference to the use of flash.