A dual focal length optical system includes a first optical system and a second optical system. The first optical system is positioned along an optical axis and includes an optical structure having an object side surface and an image side surface. The object side surface and the image side surface include a refractive surface portion and a reflective surface portion. The first optical system has a focal length. The second optical system is positioned on the same optical axis and has a focal length. The focal length of the first optical system is longer than the focal length of the second optical system.