We evaluated the abilities of 6 infrared-triggered camera systems (TrailMaster 1500, TrailMaster 500, Buckshot RTV, Buckshot Scout, CamTrakker, and DeerCam) to detect 3 sizes of animal models at 2 heights above ground and from 3 distances. We also determined the size of the infrared detection zone and the relative sensitivity of different passive camera systems. All camera systems tested had a detection zone that was narrow in the vertical dimension (3–7°). Except for the TrailMaster 500, all systems also had a detection zone that was narrow in the horizontal dimension (<10°). Sensitivity varied among camera systems. Most performed well at default or high sensitivities; the CamTrakker and the Buckshots set at highest sensitivity produced the most detections. All systems except the Buckshot RTV performed better at lower ambient temperatures. We review technical aspects of infrared-triggered photography and recommend how researchers can improve their success in detecting animals by selecting the appropriate system for their study area and target species and by careful placement and precise alignment of camera units in the field.