1. A method for calculating a distance from a camera to an object, comprising acts of: obtaining a first image of an object employing a first set of parameters; obtaining a second image of the object employing a second set of parameters; generating a first estimate of the distance from the camera to the object such that the first estimate is obtained from at least the first image and the second image using depth-from-defocus; obtaining a third image of the object employing a third set of parameters, wherein the third set of parameters are based, at least in part, on the first estimate; obtaining a fourth image of the object employing a fourth set of parameters, wherein the fourth set of parameters are based, at least in part, on the first estimate; and generating a second estimate of the distance from the camera to the object such that the second estimate is obtained from at least the third image and the fourth image using depth-from-defocus, the calculated distance from the camera to the object being based at least in part on the second estimate.