The confocal microscope has two matched light sources: a first light source (1) and a second light source (8). The light sources (1,8) are arranged to illuminate opposite sides of a modulating mask (6). The light either reflecting from or passing through the modulating mask (6) is then used to illuminate an object O supported on a mount (5). The microscope is arranged so that the object O is mounted on the opposite side of the mask (6) to a camera (7) such that light reflected from the object O passes through the modulating mask (6) before being captured by the camera (7). Subtraction of the image produced using the second light source (8) from the image produced using the first light source (1) generates a confocal image that contains substantially less noise than is possible with available confocal microscopy apparatus.