Olympus Imaging Corporation

Takeshi Hosoya

Tomoyuki Satori

Masahito Watanabe

Eiji Shirota

Tetsuya Toyoda

Yasuharu Yamada

Tetsuya Yanai

Akinori Nishio

Minoru Ueda

Mayu Miki

Atsujiro Ishii

Akiko Naito

An image pickup apparatus includes: a zoom lens; an image pickup element having an image pickup surface which receives an image which has been formed by the zoom lens, and converts to an electric signal; a shading correction parameter storage section which stores a shading correction parameter which differs at a front-surface side and a rear-surface side with respect to a center of an image, which is for correcting asymmetric shading at the front-surface side and the rear-surface side of the zoom lens; and a shading correction section which carries out correction operation of an image which has been picked up by the image pickup element, based on the shading correction parameter of the shading correction parameter storage section. When an object having a uniform brightness is captured, at any state from the wide angle end to the telephoto end, the zoom lens satisfies conditional expression (A).

Image pickup apparatus having optical path reflecting zoom lens

A zoom lens comprises in order from an object side, a first lens unit, a second lens unit, a third lens unit, a fourth lens unit, and a fifth lens unit having, respectively, a positive, negative, positive, negative, and positive refractive power. At the time of zooming from a wide angle end to a telephoto end, the first, third, and fourth lens units move toward the object side. A distance between the first and second lens units increase, a distance between the second and third lens units decrease, a distance between the third lens unit and the fourth lens unit changes, and a distance between the fourth lens unit and the fifth lens unit increases. The zoom lens satisfies the following expressions:1.54&#x3c;&#x3b2;/&#x3b2;&#x3c;3.0&#x2003;&#x2003;(1a)1.0&#x3c;&#x3b2;/&#x3b2;&#x3c;5.0&#x2003;&#x2003;(2)1.0&#x3c;&#x3b2;/&#x3b2;&#x3c;3.0&#x2003;&#x2003;(3).

Zoom lens and image pickup apparatus using the same

An image pickup apparatus includes a zoom lens, and an image pickup element having an image pickup surface which receives optically an image formed by the zoom lens, and which converts the image received to an electric signal. The image pickup apparatus satisfies the following conditional expressions (1) Lv 1 Er/Lv 1 EL&#x3c;0.49, (2) 0.93&#x3c;Lv 1 Ef/IHs, and (3) Lv 1 Ef/Lv 1 Er&#x3c;0.99.

A wide angle zoom lens, includes, from an object side in the following order: a first lens group that has a negative refractive power; a second lens group that has a positive refractive power; and a third lens group. When variable magnification is carried out from a wide angle end to a telephoto end, the first and second lens groups move while the third lens group remains fixed, so that an air space between the first lens group and the second lens group becomes narrow and that a space between the second lens group and the third lens group becomes wide. The first and second lens groups each include at least one positive lens and one negative lens. The third lens group includes one positive or negative meniscus lens whose convex surface faces an image surface. The following conditional expressions (1) and (2) are satisfied:1.4&#x2266;|1|/&#x2266;1.8&#x2003;&#x2003;(1); and1.7&#x2266;2/&#x2266;2.1&#x2003;&#x2003;(2)where f1 is a focal length of the first lens group of the wide angle zoom lens; f2 is a focal length of the second lens group of the wide angle zoom lens; and fw is a focal length of the entire system at the wide angle end of the wide angle zoom lens.

Wide angle zoom lens and image pickup device using the same

The invention relates to a zoom lens which, albeit being of simplified construction, makes sure brightness and holds back fluctuations of astigmatism, and facilitates making sure being fast and the angle of view and the zoom ratio at the wide-angle end. The zoom lens comprises a first group Gof positive power, a second group Gof negative power and a third group Gof positive power, with a stop S between the second group Gand the third group G. Upon zooming from the wide-angle end to the telephoto end, the first group G, the second group G, and the third group Gmoves; the second group Gmoves toward the object side after moving toward the image side; the first group Gand the third group Gare positioned on the object side at the telephoto end with respect to the wide-angle end. The first group Gcomprises one negative lens and one or two positive lenses, and the second group Gcomprises a first negative meniscus lens convex on its object side, a second negative lens wherein the image side surface is larger in the absolute value of a curvature than the object side surface, and a third positive lens wherein the object side surface is larger in the absolute value of a curvature than the image side surface. Upon focusing from a far distance to a near distance, the second group Gmoves.

Growing community of inventors

Machida, Japan

Takeshi Hosoya