Used to photograph fingerprints on a smooth plane, it uses a smooth plane background to direct the incident light and the fingerprint line to diffuse the difference between the incident light to improve the contrast between the fingerprint line and the background. Equipped with four conversion rings, different models of lenses can be docked. Equipped with five-section light-shielding, each section of the light-shielding barrel connected to each other can be adjusted out of a variety of lengths of the light-shielding, in the photo-taking used to block the environment noise exposure physical evidence.