Abstract: This paper proposes an efficient algorithm for the simulation of camera imaging based on both ideal and real camera models. The simulation of exposure is accomplished in two steps. First the forward projection of the scene onto the film is performed by ray tracing. Then the irradiances of the projected area of visible scene are calculated. By exploring the ray coherence during forward projection, imaging synthesis can be speedup once the lens parameters are adjusted. This is significant for simulation based on real camera model. Our experiments on two geometric scenes and a large depth image demonstrate vividly the effect of camera imaging with different parameters and show the efficiency of the proposed algorithm.