This is an upgrade of the FD24-35mm f/3.5L (released in February 1978), which was a popular high-end zoom lens. Through the effective use of aspherical optical systems, an ultra-wide angle of 20mm has been achieved while maintaining image quality equivalent to a single lens.
By making the surface of the first lens element aspherical, the various aberrations such as distortion occurring with a wider angle of the zoom lens can be corrected. Furthermore, the use of a movable flare stopper for cutting unnecessary incident light flux that reduces image quality by linking with the movement of the optical system and a floating mechanism for reducing aberration resulting from shooting distance provide uniform brightness, high contrast and a high degree of expression.