Candela is the unit of light intensity at any point measured in a given beam angle. One candela is equal to the light intensity of one candle at a distance of 1 meter. When the light beam becomes more concentrated, the beam angle will be proportionally narrower. Since Candela is the luminous flux within a beam angle, the intensity (“the number of Candela”) will be higher with a narrower beam.
Why is the quantity of Candela not stated on all packaging? This is because a regular lamp radiates in all directions. Light units such as Candela are therefore only applicable for spotlights and reflector lamps.
The relationship between the above concepts in one image (in Dutch):