Abstract: A compact variable magnification objective lens system with interchangeable lens components comprising, from front to rear, a first lens component of positive power, a second lens component of negative power and a third lens component of positive power. The focal length of the entire system can be changed by interchanging the second lens component by another lens component having a different refractive power from that of the second lens component and by shifting the first lens component simultaneously.

Abstract: An optical reading head is described which is particularly designed to read codes generally formed by fluorescent or phosphorescent bars. The codes are carried by a support, such as an envelope which moves past the head at a relatively high speed. The support carrying the code is illuminated from a light source through a set of outgoing optical fibers, and the modulated light retransmitted by the code markings is conveyed through a set of incoming optical fibers to a processing device. Such a reading head is particularly adapted for use in a postal sorting system.