1. A method of refocusing an image, the method comprising: in a processor, obtaining a set of refocused images generated from a single captured light field image comprising a plurality of pixels and representing a scene, wherein each refocused image comprises an image of the scene at a distinct focal depth; in the processor, determining refocus depths for at least a portion of the captured image; storing the refocus depths in a look-up table; and in the same or a different processor, refocusing at least a portion of the captured image at a desired refocus depth determined from the look-up table; wherein determining refocus depths for at least a portion of the captured image comprises, for each of at least a subset of the pixels, determining the refocus depth for the pixel by searching other pixels surrounding the pixel until a pixel with a known refocus depth is found.