Canon Kabushiki Kaisha

Other

Nalux Co., Ltd.

Nakato Laboratory, Inc.

Keiji Ikemori

Tsunefumi Tanaka

Nozomu Kitagishi

Sadatoshi Takahashi

Masatake Kato

Kikuo Momiyama

Takashi Matsushita

Kazuo Tanaka

Keiji Ohtaka

Hiroki Nakayama

Shigeo Yoshida

Akira Tajima

Tohru Yamamoto

Hatsumi Ikari

Takeshi Koyama

Yoshinori Itoh

Ichiro Ohnuki

Masaharu Eguchi

Hideo Ukuda

Kouji Oizumi

Hiroshi Yamamoto

Yasuyuki Yamada

Shigeyuki Suda

Yasuhisa Sato

Shoichi Shimura

Daisuke Seki

Koutaro Yano

Shin Yamaguchi

Kenta Ishii

Hirokazu Ichiki

Tetsuya Zenko

Chang Shih-Yuan

An imaging optical system wherein the number of lenses is three to seven, one to four lenses, each of which is an aspheric lens in which radius of curvature of each of both surfaces is infinity in the paraxial region and which has a power of the third-order aberration region in the peripheral area are provided, the first lens from the object side is a negative lens or the aspheric lens, the relationship

Imaging optical system

An anti-fog article is obtained by coating a substrate with an anti-fog coating material to form thereon an anti-fog coating film that is hydrophillic, moisture-absorptive, insoluble and excellent in surface hardness. The anti-fog coating material contains a polyacrylic acid compound, polyvinyl alcohol and acetylacetone, and optionally sodium silicate.

Anti-fog coating material and method of preparing an anti-fog article

A camera, or an underwater camera in particular, includes a photo-taking optical unit for photo-taking an object, and a viewfinder optical unit for observing the object, wherein an antifogging film is applied to an inner side of an optical member which is disposed in an optical path of at least one of the photo-taking optical unit and the viewfinder optical unit and which comes into contact with an external medium relative to the camera.

Camera having antifogging film

Disclosed herein is an anti-fogging coating material comprising at least one selected from the group consisting of an inorganic alkoxide, a hydrolysate of the inorganic alkoxide and a polycondensate of the hydrolysate of the inorganic alkoxide, a polyacrylic, and polyvinyl alcohol.

Anti-fogging coating material, anti-fogging coating film and anti-fogging article

An observation optical system whose eye relief is below 25 mm includes an eyepiece lens having a water absorptive antifogging coating applied on one surface thereof, and a member holding the eyepiece lens. Further, an eyeball-characteristic detecting system includes a light source for illuminating the eyeball of an observer, a light receiving element arranged on detection of the reflected light from the eyeball through the eyepiece to produce a signal, an optical member positioned in the path of the light from the light source to the light receiving element and having an antifogging coating on one surface thereof, and a circuit receptive of the signal for detecting the characteristic of the eyeball.

Observation optical system and optical apparatus having the same

An antireflection film is provided which is insoluble, wear-resistant, and weatherable, and simultaneously having non-fogging property. A non-fogging optical member employing the non-fogging antireflection film, and a process for producing the film are also provided. The non-fogging antireflection film is formed from a composition derived by polycondensation of a hydrolyzate of an inorganic alkoxide conducted in the presence of a polyacrylic acid compound.

Non-fogging antireflection film and optical member, and production

A camera system comprising a photographic lens having a plurality of lens units movable along a photographic optical axis when zooming, and a finder optic having a plurality of lens units movable along a finder optical axis when zooming, wherein the amounts of zooming movement of at least one of the lens units of the photographic lens and at least one of the lens units of the finder optic are the same.

Camera system

A photographing apparatus having at least two modes, i.e., a first mode for setting and photographing a first photographing area of a photographing area photographed by a photo-taking optical system, and a second mode for setting and photographing a second photographing area smaller than the first photographing area. The apparatus has in succession from the object side a first lens unit and a second lens unit. The first lens unit comprises a positive lens of positive refractive power and a negative lens of negative refractive power, and the second lens unit comprises a positive lens. The spacing between the first lens unit and the second lens unit is varied during the changeover between the first mode and the second mode.

Photographing apparatus having a trimming photographic mode

A camera system comprising a group of lenses arranged on a common first optical axis, a photographic lens including at least one movable lens member on a second optical axis and having an image plane, a main reflex mirror arranged on forward movement of the movable lens to be inserted into a space behind it on the second optical axis so that the optical axis of the photographic lens is bent, and a supplementary reflex mirror for reflecting the light beam from the main reflex mirror to the lens group.

A varifocal lens is disclosed, comprising, from front to rear, a first lens unit of negative power, a second lens unit of positive power, and a third lens unit of negative power, all these lenses being moved along a common optical axis when the focal length of the entire lens system varies, wherein all the lens units each are constructed with either one lens, or two lenses, the total number of lenses being limited to 3 or 4, while still maintaining good optical performance.

Compact varifocal lens

A zoom lens comprising, from front to rear, a first lens group of negative power, a second lens group of positive power and a third lens group of negative power, wherein as zooming from the wide-angle end to the telephoto end is performed by moving the first, second and third lens groups, the second and third lens groups both are directed forward and the speed of movement of the third lens group is faster than that of movement of the second lens group, the zoom lens satisfying the following conditions:

Compact zoom lens

A zoom lens comprising, from front to rear, a first lens unit of negative power, a second lens unit of positive power and a third lens unit of negative power, the second and third lens units being moved to effect zooming, and the third lens unit having its focal length f.sub.3 laid in the following range:

In the disclosed zoom lens three or more zoom components are located on the image side of a stationary component which is stationary during both focusing and zooming. The three or more zoom components are moved during zooming and are provided into a front portion which is moved for focusing, and a rear portion which remains stationary during focusing. The front focusing portion includes at least two components which move together when focusing, but when zooming move relative to each other so as to change the focal length or power of the front portion. This has the advantageous effect of reducing the difference between the amount the front portion needs to move for focusing at the wide angle position and at telephoto position.

Focusing method for zoom lens

This specification discloses a magnification changing lens which has, in succession from the object side, a first lens unit of negative refractive power, a second lens unit of positive refractive power, a third lens unit of negative refractive power and a fourth lens unit of positive or negative refractive power and in which at least the second and third lens unit are moved toward the object side to thereby accomplish the magnification change from the wide angle end to the telephoto end. This magnification changing lens particularly satisfies the following condition:

Magnification changing lens

A zoom lens including, from front to rear, a first lens unit of positive power, a second lens unit of negative power and a third lens unit of positive power, wherein for a standard focal length range at least the first and second lens units move simultaneously and independently of each other, and to obtain a focal length beyond the standard range, at least the second lens unit moves, whereby the locus of movement of the first lens unit bends at an end of the standard range, and as the standard range is exceeded, the first lens unit either remains stationary or moves forward.

Growing community of inventors

Yokohama, Japan

Keiji Ikemori