Traditional optical imaging faces an unavoidable trade-off between resolution and depth of field (DOF). To increase resolution, high numerical apertures (NA) are needed, but the associated large angular uncertainty results in a limited range of depths that can be put in sharp focus. Plenoptic imaging was introduced a few years ago to remedy this trade off. To this aim, plenoptic imaging reconstructs the path of light rays from the lens to the sensor. However, the improvement offered by standard plenoptic imaging is practical and not fundamental: the increased DOF leads to a proportional reduction of the resolution well above the diffraction limit imposed by the lens NA. In this paper, we demonstrate that correlation measurements enable pushing plenoptic imaging to its fundamental limits of both resolution and DOF. Namely, we demonstrate to maintain the imaging resolution at the diffraction limit while increasing the depth of field by a factor of 7. Our results represent the theoretical and experimental basis for the effective development of the promising applications of plenoptic imaging.Plenoptic imaging (PI) is a novel optical method for recording visual information [1]. Its peculiarity is the ability to record both position and propagation direction of light in a single exposure. PI is currently employed in the most diverse applications, from stereoscopy [1][2][3], to microscopy [4][5][6][7], particle image velocimetry [8], particle tracking and sizing [9], wavefront sensing [10][11][12][13] and photography, where it currently enables digital cameras with refocusing capabilities [14,15]. The capability of PI to simultaneously acquire multiple-perspective 2D images brings it among the fastest and most promising methods for 3D imaging with the available technologies [16]. Indeed, high-speed and large-scale 3D functional imaging of neuronal activity has been demonstrated [7]. Furthermore, first studies for surgical robotics [17], endoscopic application [18] and blood-flow visualization [19] have been performed.The key component of standard plenoptic cameras is a microlens array inserted in the native image plane, that reproduces repeated images of the main camera lens on the sensor behind it [1,15]. This enables reconstruction of light paths, employed, in post-processing, for refocusing different planes, changing point of view and extending depth of field (DOF) within the acquired image. However, a fundamental trade-off between spatial and angular resolution is naturally built in standard plenoptic imaging. If N tot is the total number of pixels per line on the sensor, N x the number of microlenses per line, and N u the number of pixels per line associated with each microlens, then N x N u = N tot . Essentially, standard PI gives the same resolution and DOF one would obtain with a N u times smaller NA. The final advantage is thus practical rather than fundamental, and is limited * francesco.pepe@ba.infn.it † milena.dangelo@uniba.it to higher luminosity (hence SNR) of the final image and parallel acquisition of m...