Abstract: Provided is an eyepiece optical system including at least three lenses disposed in order from an observation object (Ob) along an optical axis. A final lens disposed closest to an eye point (EP) (corresponds to the third lens (L3) in FIG. 1) is fixed when adjusting the diopter, and the following conditional expressions (1) and (2) are satisfied: 2.2<|fe/fa<6.0??(1) 0.5<|Re2/fa|<5.0??(2) where fe denotes a focal length of the final lens, fa denotes a focal length of the total eyepiece optical system (EL), and Re2 denotes a radius of curvature of the eye point (EP) side lens surface of the final lens. When an optical surface is aspherical, a paraxial radius of curvature is used for calculation.

Abstract: Provided is an eyepiece optical system including at least three lenses disposed in order from an observation object (Ob) along an optical axis. A final lens disposed closest to an eye point (EP) (corresponds to the third lens (L3) in FIG. 1) is fixed when adjusting the diopter, and the following conditional expressions (1) and (2) are satisfied: 2.2<|fe/fa<6.0??(1) 0.5<|Re2/fa|<5.0??(2) where fe denotes a focal length of the final lens, fa denotes a focal length of the total eyepiece optical system (EL), and Re2 denotes a radius of curvature of the eye point (EP) side lens surface of the final lens. When an optical surface is aspherical, a paraxial radius of curvature is used for calculation.

Abstract: Provided is an eyepiece optical system including at least three lenses disposed in order from an observation object (Ob) along an optical axis. A final lens disposed closest to an eye point (EP) (corresponds to the third lens (L3) in FIG. 1) is fixed when adjusting the diopter, and the following conditional expressions (1) and (2) are satisfied: 2.2<|fe/fa|<6.0??(1) 0.5<|Re2/fa|<5.0??(2) where fe denotes a focal length of the final lens, fa denotes a focal length of the total eyepiece optical system (EL), and Re2 denotes a radius of curvature of the eye point (EP) side lens surface of the final lens. When an optical surface is aspherical, a paraxial radius of curvature is used for calculation.

Abstract: Providing an eyepiece optical system 10 comprising: an eyepiece system 11; and an optical member 12 having a meniscus shape disposed to an eye side of the eyepiece system 11, the following conditional expression being satisfied: 2.00<|R|/fe<22.00 where fe denotes a focal length of the eyepiece system 11 when a diopter of the eyepiece system 11 is 0 (m?1), and R denotes a radius of curvature of the surface having the meniscus shape, and the optical member 12 with a meniscus shape having a concave surface facing the eye side.

Abstract: Provided is an eyepiece optical system including at least three lenses disposed in order from an observation object (Ob) along an optical axis. A final lens disposed closest to an eye point (EP) (corresponds to the third lens (L3) in FIG. 1) is fixed when adjusting the diopter, and the following conditional expressions (1) and (2) are satisfied: 2.2<|fe/fa|<6.0??(1) 0.5<|Re2/fa|<5.0??(2) where fe denotes a focal length of the final lens, fa denotes a focal length of the total eyepiece optical system (EL), and Re2 denotes a radius of curvature of the eye point (EP) side lens surface of the final lens. When an optical surface is aspherical, a paraxial radius of curvature is used for calculation.

Abstract: An imaging lens SL comprising, in order from an object side: a first group G1 having positive refractive power; an aperture stop S; a second group G2 having positive refractive power; and a third group G3 having negative refractive power; upon focusing from infinity to a close object, the first group and the second group moving independently along an optical axis toward the object side, the first group including, in order from the object side, a front group having negative refractive power, and a rear group having positive refractive power, and the front group consisting of, in order from the object side, a positive lens and a negative lens, thereby providing an imaging lens capable of obtaining excellent optical performance upon focusing from infinity to a close object, with downsizing the optical system with a simple lens construction, an optical apparatus and a method for manufacturing the imaging lens.

Abstract: Providing an eyepiece optical system 10 comprising: an eyepiece system 11; and an optical member 12 having a meniscus shape disposed to an eye side of the eyepiece system 11, the following conditional expression being satisfied: 2.00<|R|/fe<22.00 where fe denotes a focal length of the eyepiece system 11 when a diopter of the eyepiece system 11 is 0 (m?1), and R denotes a radius of curvature of the surface having the meniscus shape, and the optical member 12 with a meniscus shape having a concave surface facing the eye side.

Abstract: An imaging lens SL mounted in a single lens reflex digital camera 1 is composed of, in order from an object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power. Upon focusing on a near-distance object from an infinitely distant object, a configuration is that at least any one of the first lens group G1 and the second lens group G2 is moved to the object side to vary a distance between the first lens group G1 and the second lens group G2. Accordingly, a downsized imaging lens having a small moving amount upon shooting a close range object, in which various aberrations are well corrected is provided.

Abstract: An imaging lens SL mounted in a single lens reflex digital camera 1 is composed of, in order from an object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power. Upon focusing on a near-distance object from an infinitely distant object, a configuration is that at least any one of the first lens group G1 and the second lens group G2 is moved to the object side to vary a distance between the first lens group G1 and the second lens group G2. Accordingly, a downsized imaging lens having a small moving amount upon shooting a close range object, in which various aberrations are well corrected is provided.

Abstract: An imaging lens SL comprising, in order from an object side: a first group G1 having positive refractive power; an aperture stop S; a second group G2 having positive refractive power; and a third group G3 having negative refractive power; upon focusing from infinity to a close object, the first group and the second group moving independently along an optical axis toward the object side, the first group including, in order from the object side, a front group having negative refractive power, and a rear group having positive refractive power, and the front group consisting of, in order from the object side, a positive lens and a negative lens, thereby providing an imaging lens capable of obtaining excellent optical performance upon focusing from infinity to a close object, with downsizing the optical system with a simple lens construction, an optical apparatus and a method for manufacturing the imaging lens.

Abstract: A single lens reflex camera has a finder optical system that observes an image formed on a reticle by an objective lens, and a photometric device that measures light transmitted through the reticle via at least a part of the finder optical system, at a position shifted from an optical axis of the finder optical system. The finder optical system comprises a Fresnel lens surface which transmits light from the objective lens, and the Fresnel lens surface is positioned so that the center of the Fresnel lens surface is shifted in a direction to cross the optical axis of the finder optical system according to a position of the photometric device.

Abstract: A single lens reflex camera has a finder optical system that observes an image formed on a reticle by an objective lens, and a photometric device that measures light transmitted through the reticle via at least a part of the finder optical system, at a position shifted from an optical axis of the finder optical system. The finder optical system comprises a Fresnel lens surface which transmits light from the objective lens, and the Fresnel lens surface is positioned so that the center of the Fresnel lens surface is shifted in a direction to cross the optical axis of the finder optical system according to a position of the photometric device.

Abstract: An eyepiece lens includes first lens group G1 having a negative refracting power including a negative meniscus lens with a concave surface facing eyepoint E.P side, second lens group G2 having a positive refracting power including a lens with both convex surfaces on both ends, and third lens group G3 having a negative refracting power including a negative lens. The first–third lens groups are arranged in an order from eyepoint E.P side, and the eyepiece lens is capable of varying a diopter by moving the second lens group along an optical axis. The eyepiece lens is configured by aspherical surfaces to make the positive refracting power weak while at least one surface of the convex surfaces of the lens deviates from the optical axis. Further, conditions of a following formula are satisfied: 1.6<f1/f3<2.5 ?0.

Abstract: An eyepiece lens includes first lens group G1 having a negative refracting power including a negative meniscus lens with a concave surface facing eyepoint E.P side, second lens group G2 having a positive refracting power including a lens with both convex surfaces on both ends, and third lens group G3 having a negative refracting power including a negative lens. The first—third lens groups are arranged in an order from eyepoint E.P side, and the eyepiece lens is capable of varying a diopter by moving the second lens group along an optical axis. The eyepiece lens is configured by aspherical surfaces to make the positive refracting power weak while at least one surface of the convex surfaces of the lens deviates from the optical axis. Further, conditions of a following formula are satisfied: 1.6<f1/f3<2.5 ?0.

Abstract: In order to provide an eyepiece lens which has a sufficiently long eye relief and a high magnification, there is provided an eyepiece lens for observing an image formed by an objective lens through an erect system, at least comprising a first lens group 4 having a positive refracting power and a second lens group 3 having a negative refracting power in this order from the side of an observer, and satisfying the following condition: −3<SF1<−1  (1) where SF1 indicates a shape factor of the first lens group 4, and SF indicates a shape factor of the lens group, which is defined by: SF=(Rs+RE)/(Rs−RE), where Rs indicates a radius of curvature of a lens surface which is closest to the object side and RE indicates a radius of curvature of a lens surface which is closest to the observer side.

Abstract: In order to provide an eyepiece lens which has a sufficiently long eye relief and a high magnification, there is provided an eyepiece lens for observing an image formed by an objective lens through an erect system, at least comprising a first lens group 4 having a positive refracting power and a second lens group 3 having a negative refracting power in this order from the side of an observer, and satisfying the following condition:

Abstract: A real image viewfinder of an optical device includes an eye piece through which an optical axis may be viewed with respect to a target frame. The target frame may be used for centering an optical image on an image forming plane and also for autofocus of the optical device. The real image viewfinder includes a first prism for redefining an optical axis within the optical device. The first prism has a pair of reflective planes joined about a first ridge line. The first ridge line generally includes a number of manufacturing flaws which are noticeable by the photographer. Thus, viewfinder components are shifted by a predetermined amount to present the first ridge line in an area of the viewfinder which is different from the target frame as viewed through the eye piece. Likewise, the real image viewfinder includes a second prism having a second ridge line which is also shifted away from the target frame as viewed through the eye piece.

Abstract: A real-image zoom finder has an objective lens having a positive refractive power, and an eyepiece lens which is used for observing a real image of an object formed via the objective lens and has a positive refractive power. The objective lens includes, in the order from the object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power, and attains zooming by moving at least the second lens unit along the optical axis. The objective lens satisfies the following conditions:-0.6<(R2+R1)/(R2-R1)<00.3<.vertline.f3.vertline./fT<0.

Abstract: An underwater wide angle lens is provided, in succession from the object side, with a fore group comprising a first lens group having negative refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power, and a rear group comprising a fifth lens group having positive refractive power and a sixth lens group having positive refractive power. Preferably, the fifth lens group and/or the sixth lens group is a cemented lens and focusing is effected by one or more of the second to sixth lens groups. Preferably each of the first lens group, the second lens group and the third lens group is a meniscus lens having its convex surface facing the object side.