104 is employed nonetheless it will be appreciated that in variants of the embodiment fewer or more lens elements could be employed the former limiting image quality with the latter potentially improving quality albeit at higher cost the lens elements comprise an aperture group including a positive front collecting lens 104 1 disposed immediately adjacent the filter 102 in the embodiment shown lens 104 1 includes a meniscus shape in a central portion of the lens 104 1 nearest the optical axis 114 with the object side surface surface 3 being convex further surface 4 of lens 104 1 is an aspheric surface characterized by an aspheric inflection point in the central region of lens 104 1 surface 4 is concave accordingly surface 4 curves toward the image side toward sensor 106 with increasing radius from optical axis 114 however with a further increasing radius from optical axis 114 towards the periphery of lens 104 1 surface 4 changes direction and bends toward an object side away from sensor 106 thus forming an aspheric inflection point in the illustrated embodiment the filter 102 is shown as a separate planar element to the lens assembly 104 however in variations of the invention the filter including the aperture stops for the visible and ir imaging systems can be provided as a coating on the front surface surface 3 of the collecting lens 104 1.