A compound lens is a lens system made up of two or more individual lens elements combined to function as a single optical unit. By using multiple elements, lens designers can reduce optical aberrations such as distortion, chromatic aberration, and spherical aberration. Compound lenses often allow for larger maximum apertures, improved resolution, and better image quality compared to single-element lenses. They are commonly used in modern cameras, from compact cameras to professional DSLR and mirrorless systems, providing sharper, clearer, and more accurate photographs across a variety of shooting conditions.