A 3D camera for determining distances to regions in a scene comprising: a photosurface having a plurality of pixels each of which comprises a circuit having a light sensitive element that provides a current responsive to light incident thereon, wherein the circuit comprises, at least one amplifier inside the pixel, having an input and an output; at least one feedback capacitor separate from the light sensitive element and connected between the input and output of each of the at least one amplifier; at least one controllable connection through which current flows from the light sensitive element into the input of the at least one amplifier; a light source; and, a controller that, controls the light source to illuminate the scene with light, opens and closes the at least one controllable connection to gate or modulate current from the light sensitive element of a pixel in the photosurface responsive to the time dependence of the gating or modulation of the light, controls the at least one controllable connection to provide a current for correcting biases caused by at least one of background light or dark current, and determines a distance to a region imaged on the pixel responsive to an amount of charge integrated on the feedback capacitor responsive to the gated or modulated current and the corrected biases.