Stray light (also called flare) can adversely affect the image quality or application performance of a camera system. Testing for stray light is critical for understanding limitations of camera system performance. Stray light is any light that reaches the detector (i.e., the image sensor) other than through the designed optical path. Depending on the mechanism causing stray light, it can introduce false colors and phantom objects (ghosts) within the scene, reduce contrast over portions of the image (veiling glare), and effectively reduce system dynamic range. In this paper, we present an overview of stray light testing for digital camera systems, as well as lessons learned and various technical elements to consider. These elements include the radiometric (e.g., brightness) and geometric (e.g., size) properties of the light source and test setup. We focus on a test approach that involves illuminating the camera with a small, bright light source and describe how certain elements of the test can impact a measurement.