An apparatus for capturing a test image that can be used in calibrating a camera. In some embodiments, the apparatus reflects light toward the lens of a camera such that a central target subject is captured at the center while a reflection of that same target subject is reflected to each corner of the test image. The apparatus includes an adapter for holding a set of mirrors in the field of view of the camera, each mirror reflecting a target at the center of the field of view. The apparatus of some embodiments is configurable to change the angle of the mirrors based on a focal length of the lens of the camera.