1. A method for focusing a plenoptic imaging system, the plenoptic imaging system comprising a primary imaging subsystem, a secondary imaging array, and a sensor array, the method comprising: receiving a plenoptic image of an object captured by the sensor array; adjusting a distance z 2 to position the secondary imaging array at the primary image location of the primary imaging subsystem, wherein z 2 is a distance between the primary imaging subsystem and the secondary imaging array, said z 2 adjustment based on increasing a high frequency content in the plenoptic image; and adjusting a distance z 3 to position the sensor array at the pupil image location of the secondary imaging array, wherein z 3 is a distance between the secondary imaging array and the sensor array, said z 3 adjustment based on reducing a blur in a pupil image function of the plenoptic imaging system.