Zoom lens system for camera - has fixed front group of lenses and rear group which is moved to focus object

摘要

The middle lenses, of a zoom lens system for a camera, consist of a front group (GF) and a rear group (GR). The first group (GF), starting from the object side, consists of at least two convergent lenses with their pronounced convex sides facing the object. The group (GF) also includes a divergent lens with a pronounced concave side facing towards the image. The combined group (GF) of lenses has a resultant convergent refractive power. The lens of the rear group (GR) which is closest to the object has a convex face on the side facing the object. The group (GR) has a resultant convergent refractive power and only this rear group is moved along the optical axis in order to focus the object. USE - Zoom cameras.