A reliable and repeatable accuracy of focus measurement device to measure the focus accuracy of cameras that employ a different light path between the lens and the focusing sensor and between the lens and the film or image sensor. The measurement device includes a frame having a substantially planar front face with a focusing target located thereon, and at least one depth-of-field ruler coupled to the frame with a transverse axis falling within a front face plane and a long axis that is angularly adjustable with respect to the front face plane.