The invention relates to a collimator for testing a camera (6), comprising a collimator housing (1), wherein the collimator housing (1) has a longitudinal wall (8, 9) and two end walls (10, 11), the first end wall (10) having a light source (2) and the second end wall (11) having a lens (5), a reticle (4) being disposed between the lens (5) and the light source, with the reticle (4) being disposed obliquely with respect to the lens (5) and/or obliquely with respect to the longitudinal wall (8, 9) in the collimator housing (1).