Variable aperture optical device having a microshutter

In certain embodiments, a detection device includes a structure having an entrance that permits radiation to enter the structure and a radiation detector operable to detect radiation that enters the structure. The device also includes a microshutter array coupled to the structure and aligned with the entrance, the array comprising a plurality of microshutter cells operable to move between a first position in which that microshutter cell prevents radiation of a first wavelength from passing through a portion of the entrance and a second position in which that microshutter cell permits the radiation of the first wavelength to pass through the portion of the entrance. The device further includes an actuating device operable to define a first entrance pupil having a first f-number by moving a plurality of microshutter cells associated with the first f-number.