  Nonclassical states of light are necessary resources for quantum technologies
such as cryptography, computation and the definition of metrological standards.
Observing signatures of nonclassicality generally requires inferring either the
photon number distribution or a quasi-probability distribution indirectly from
a set of measurements. Here, we report an experiment in which the nonclassical
character of families of quantum states is assessed by direct inspection of the
outcomes from a multiplexed photon counter. This scheme does not register the
actual photon number distribution; the statistics of the detector clicks alone
serve as a witness of nonclassicality, as proposed by Sperling et al. in Phys.
Rev. Lett. 109, 093601 (2012). Our work paves a way for the practical
characterisation of increasingly sophisticated states and detectors.
