1. A method for image acquisition and conversion comprising spatially low-pass filtering a received light intensity field by an acquisition lens, producing from at least a portion of said spatially low-pass filtered light intensity field a spatially up-sampled image using an image sensor, the up-sampled image having a first spatial resolution finer than the Rayleigh criterion for the acquisition lens by at least a factor of 2, the up-sampled image comprising samples of a first bit depth, and converting said up-sampled image into a multi-level image having samples with a second spatial resolution lower than said first resolution, the samples in the multi-level image having a second bit depth greater than the first bit depth, wherein said converting comprises determining, based on a model of the spatial low-pass filtering of the acquisition lens, an estimate ({circumflex over (γ)}) of at least a portion of the received light intensity field at a plurality of the samples within the multi-level image.