A standard, non-motorized, diagnostic x-ray beam-limiting device whose aperture size/length/shutter assembly must be manually adjusted in order to match the size of the x-ray beam to the size of the x-ray cassette in use. It includes designs with manual controls that operate one or more shutter pairs and also designs that require the addition or removal of attachments or extensions that allow the operator to alter the size and shape of the exit beam from a cone or cylinder. An x-ray collimator is used to limit the effects of scattered radiation on image quality and to provide patient protection by eliminating exposure to non-target body areas.