Arnold International
Zoom lens
 A zoom lens for primary use with a projection screen television system is disclosed having five lens groups, in sequential order from the enlarging side, of negative, positive, positive, negative, and positive refractive power. The first lens group and the fifth lens group are fixed, and the axial positions of the second lens group, the third lens group, and the fourth lens group vary when zooming so as to provide a change in magnification and to correct for shifting of the image surface which otherwise would occur with zooming. Specified conditions are satisfied in order to provide a zoom lens that is compact, is well-corrected for aberrations over the entire range of zoom, has a sufficient back focus on the reducing side for insertion of lens components needed for projecting color images, is nearly telecentric on its reducing side, and provides a sufficiently bright image with a wide-angle of view. 
Fuji Photo Optical Co., Ltd.
G G
G02B G02B
inventional inventional
Chikara Hiroshi Akiko
Yamamoto Yamada Nagahara