Minolta Camera Kabushiki Kaisha

Mitsuko Date

Takashi Okada

Tetsuo Kohno

Yoshinobu Kudo

Kazuo Kimura

Hisashi Tokumaru

Hiroyuki Matsumoto

Akira Fukushima

A compact zoom lens system comprises a front negative lens component and a rear positive lens component with a variable air space between the front and the rear lens components. The front negative lens component consists of two lens elements and the rear lens component consists of two or three lens elements. A plurality of aspherical surfaces are employed for the compact zoom lens system. Furthermore, some zoom lens system includes an additional negative lens component having a weak refractive power behind the rear lens component.

Compact zoom lens system

A compact size zoom lens system ranging to a wide field angle and having a high zoom ratio of up to 10. The zone lens system is composed of, from the object to the image side, a positive first lens group, a negative second lens group, a positive third lens group and a negative fourth lens group, and fulfills the following conditions:

Zoom lens system having high zoom ratio ranging to wide field angle

In a triplet type objective for a compact lens shutter camera with a diaphragm arranged behind the lens system, the first and the second lens elements are formed of plastic and the third lens element is formed of glass, so that it is advantageous in manufacturing cost and weight. Therefore, an F No. of the objective is small and aberrations, for example astigmatic difference, are corrected well.

Triplet type objective with a diaphragm arranged behind the lens system

Growing community of inventors

Sakai, Japan

Mitsuko Date