From what I've read and watched, a CPL can cut reflections/glare and increase saturation (mainly the blues). Also, these effects can be adjusted by simply rotating the filter. What is not being discussed often is the part that it's also somewhat of a ND filter in that it usually adds one or two stops.
My question is - can that 2 stops also be adjusted or completely turned off? Could a CPL end up as a normal glass without any effect (i.e. no increase in saturation, not cutting of reflection, and no additional stops), kind of like the UV filter where it's mostly used simply as a protection?