Geometric construction of the light field resolution criterion introduced in . In these figures conjugate images of the microlens array and image sensor are depicted on the object side of the microscope. Taking the magnification factor into account, the effective object-side pitch of the conjugated lenslet is *d*/M and its effective focal length is *f*_{μlens}/M^{2}. **(a)** The resolution criterion holds when point sources **p**_{1} and **p**_{2} are at sufficient depth |*z*| that they form diffraction limited spots on the sensor. Under this condition, the discriminability of the spots can be determined by simple geometric construction using similar triangles. Here, *c* is a constant that allows us to specify a particular resolution criterion (e.g., *c* = 1.22 selects the Rayleigh 2-point criterion, and *c* = 0.94 selects the Sparrow 2-point criterion [, p. 340]). In this paper, we use the Sparrow 2-point criterion since it is best suited for measuring where contrast drops to zero between two point projections measured in a digital image [, p. 340]. **(b)** To see where this resolution criterion holds, we measure the diameter *b* of the blur disk predicted using geometric optics. Our approximation is valid when this diameter is less than the diameter of a diffraction-limited spot (i.e. when *b* < *cλ*/NA).

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