Image quality until now found only in a fixed focal length lens the definitive large aperture aps c format standard zoom lens what makes a standard lens ideal for you certain important qualities are required such as fast maximum aperture versatility for snap shots portraiture and indoor photography plus a good combination of a wide range of focal lengths in a compact design sigma 18 35mm f18 dc hsm is the first zoom lens ever to achieve a maximum aperture of f18 throughout the zoom rang