This lens utilizes a front group interchangeable system made up of a front unit containing the front lens group and the focusing unit containing the rear lens group, the automatic diaphragm control mechanism and focal adjustment mechanism. In addition to being compact and improving operability and portability, the extravagant lens design using numerous lens elements has substantially increased lens performance such as resolution and color balance. It is also possible to easily change the focal length by combining various front units and the common focusing unit used in each lens.
Focusing is performed using a rack-and-pinion method. It also operates smoothly when attached to cameras heavily equipped with the main camera unit, a motor drive and Film Chamber 250.
The Canon FL fully automatic diaphragm control was also achieved by incorporating the diaphragm control mechanism into the rear focusing unit.