  We report nonclassical aspects of the collective behaviour of two atoms in a
cavity by investigating the photon statistics and photon distribution in a very
broad domain of parameters. Starting with the dynamics of two atoms radiating
in phase into the cavity, we study the photon statistics for arbitrary
interatomic phases as revealed by the second-order intensity correlation
function at zero time $g^{(2)}(0)$ and the Mandel $Q$ parameter. We find that
the light field can be tuned from antibunched to (super-)bunched as well as
nonclassical to classical behaviour by merely modifying the atomic position.
The highest nonclassicality in the sense of the smallest $Q$ parameter is found
when spontaneous emission, cavity decay, coherent pumping, and atom-cavity
coupling are of comparable magnitude. We introduce a quantum version of the
negative binomial distribution with its parameters directly related to $Q$ and
$g^{(2)}(0)$ and discuss its range of applicability. We also examine the
Klyshko parameter which highlights the nonclassicality of the photon
distribution.
