This paper deals with measurements of the pupillary response to several kinds of input signals such as sinusoidal modulated light intensity, flashes, noise and frequency-modulated flicker light. The results are compared with one another. This turns out that the dynamic behaviour of the pupillary response to continuous input signals (sinusoidal, random) differs slightly from the behaviour of the response to flashes, while the shape of the response to frequency-modulated flicker light is quite different and resembles the far-to-near response of the pupil system.