An imaging apparatus, including imaging optical system having a lens group and an aperture stop, and a solid-state image sensor which includes a photoelectric conversion layer made of an organic material and a color filter layer with color filters of two or more colors and a separation wall. The photoelectric conversion layer has a thickness of 0.1 82 m to 1 μm, each of the color filters has a refractive index of 1.5 to 1.8, the separation wall has a width of 0.05 μm to 0.2 μm and a refractive index of 1.22 to 1.34, and the lens group and the solid-state image sensor are disposed such that the relationship between a pixel pitch D (μm) of the sensor and a maximum angle α (°) of a principal ray incident on the sensor is 45≧α≧25.D−20 where D≦2.6 μm.