Telephoto zoom is designed for full-frame L-mount mirrorless cameras, however can also be used with APS-C models where it provides a 105-300mm equivalent focal length range.. Constant f/4 maximum aperture maintains consistent illumination throughout the zoom range.. One aspherical element and one ultra-high refractive index element help to minimize distortions and spherical aberrations throughout the zoom range in order to maintain edge-to-edge sharpness and illumination.. One ultra extra-low dispersion element and three extra-low dispersion elements greatly reduce chromatic aberrations and color fringing in order to produce a high degree of clarity and color accuracy.. A double focus system employs both a linear motor and a stepping motor to deliver impressively fast, precise, and quiet autofocus performance.