  We address potential deviations of radiation field from the bosonic behaviour
and employ local quantum estimation theory to evaluate the ultimate bounds to
precision in the estimation of these deviations using quantum-limited
measurements on optical signals. We consider different classes of boson
deformation and found that intensity measurement on coherent or thermal states
would be suitable for their detection making, at least in principle, tests of
boson deformation feasible with current quantum optical technology. On the
other hand, we found that the quantum signal-to-noise ratio (QSNR) is vanishing
with the deformation itself for all the considered classes of deformations and
probe signals, thus making any estimation procedure of photon deformation
inherently inefficient. A partial way out is provided by the polynomial
dependence of the QSNR on the average number of photon, which suggests that, in
principle, it would be possible to detect deformation by intensity measurements
on high-energy thermal states.
