A time-of-flight 3D camera and related method for illuminating a camera field of view and capturing return image light are disclosed herein. In one example, the time-of-flight 3D camera includes a light source that emits source light along an optical axis, and a collimator that receives and collimates the source light to create collimated light. A refractive diffuser is tuned to the camera field of view and receives and diffuses the collimated light to create refracted light having a varying intensity profile. The refractive diffuser guides the refracted light to illuminate the camera field of view to reduce wasted source light.