Pleiades mass spectrum (left) and mass function (right) obtained by combining our data (black and magenta filled circles) with data from Lodieu et al. (2012, brown crosses). Also included is the mass spectrum and mass function of the σ Orionis cluster (~3 Myr) from Peña Ramírez et al. (2012, blue open circles). All functions are normalized to the total number of brown dwarfs in the mass interval 0.075−0.03 M_⊙ found in our survey. The agreement between the two clusters is remarkable. Vertical dotted lines stand for the hydrogen and deuterium-burning mass limits at ≈0.072 and ≈0.012 M_⊙. Vertical error bars indicate Poisson uncertainties, and horizontal error bars correspond to mass intervals. The incomplete mass bin is marked with an upper arrow. Both axes are in logarithmic scale.