No. Because it is a Circular Polarizer, it is specifically designed to be compatible with the beam-splitting optics used in the autofocus and exposure metering systems of modern digital cameras.
You will typically lose about 1.5 to 2 stops of light. Most cameras with TTL (Through-The-Lens) metering will automatically adjust the exposure to compensate for this loss.
Yes, it features front threads for stacking, but be cautious of vignetting (dark corners) when stacking multiple filters on wide-angle lenses.