1. A method for fabricating a plurality of wafer-level array cameras, comprising: disposing a lens wafer, including a plurality of lens arrays, on an image sensor wafer, including a plurality of image sensor arrays, to form a composite wafer; and dicing the composite wafer to form the wafer-level array cameras, each of the wafer-level array cameras comprising a respective one of the lens arrays and a respective one of the image sensor arrays; wherein all lenses of the lens arrays have same back focal length; wherein the step of dicing comprises dicing the composite wafer to produce wafer-level array cameras of different array sizes; and wherein the step of disposing a lens wafer comprises a single step of aligning the lens wafer with the image sensor wafer such that all lenses of the lens arrays are aligned with respective image sensors of the image sensor arrays.