Passband variations of the MegaCam r filter. Top: measured variations of the MegaCam r filters from Betoule et al. (2013). Ten measurements have been performed at different off-axis positions; larger position indices indicate larger off-axis distances. The transmissions have renormalised so that the maximum of the transmission at Position index 1 is 1. The inset shows a zoom on the cut-on of the transmissions. The legend gives the position indices associated to each colour. Bottom: the first four moments of the ten MegaCam r passbands. Each transmission is identified with a specific colour, identical in the top and bottom panels.