  The contrast of granulation is an important quantity characterizing solar
surface convection. We compare the intensity contrast at 630 nm, observed using
the Spectro-Polarimeter (SP) aboard the Hinode satellite, with the 3D radiative
MHD simulations of V{\"o}gler & Sch{\"u}ssler (2007). A synthetic image from
the simulation is degraded using a theoretical point-spread function of the
optical system, and by considering other important effects. The telescope
aperture and the obscuration by the secondary mirror and its attachment spider,
reduce the simulated contrast from 14.4 % to 8.5 %. A slight effective defocus
of the instrument brings the simulated contrast down to 7.5 %, close to the
observed value of 7.0 %. A proper consideration of the effects of the optical
system and a slight defocus, lead to sufficient degradation of the synthetic
image from the MHD simulation, such that the contrast reaches almost the
observed value. The remaining small discrepancy can be ascribed to straylight
and slight imperfections of the instrument, which are difficult to model.
Hence, Hinode SP data are consistent with a granulation contrast which is
predicted by 3D radiation MHD simulations.
