A catadioptric lens is an optical design that combines reflective (mirror) and refractive (lens) elements to form an image. More commonly referred to as a mirror lens, it allows for long focal lengths in a compact design, making it popular for wildlife, sports, and astrophotography. Catadioptric lenses are known for their unique bokeh characteristics and can minimise chromatic aberration, providing sharp and high-contrast images despite their relatively small size compared to traditional long telephoto lenses.