A lens barrel in which a lens can be moved in a direction parallel to an optical axis includes: a first frame having a cam follower and a cam follower base that holds the cam follower; and a second frame that has a cam groove engageable with the cam follower. The first frame and the second frame are moved relatively to each other along the optical axis. The cam follower base has a first end connected to the main body of the first frame via at least one thin portion, and a second end not connected to the main body. The thin portion is formed such that a thickness of the thin portion in a radial direction of the lens barrel is smaller than that of the cam follower base.

Provided is a collapsible lens barrel including a base barrel, a drive device including a linear motion member reciprocating in an optical axis direction and a drive source for driving the linear motion member, a cam frame provided with a cam groove, a drive device frame that is engaged with the cam groove and causes the drive device to reciprocate in the optical axis direction, a focus lens group frame that holds a focus lens group, and a contact part and an arm that extend from the focus lens group frame toward an object side and are engaged with the linear motion member to cause the focus lens group frame to reciprocate in the optical axis direction.

Pop-out lens systems for compact digital cameras, comprising an image sensor and a lens with a field of view FOV>60 deg and having i lens elements L1-Li starting with L1 from an object side toward an image side, each lens element Li having a respective focal length f.sub.i, the lens elements divided into two lens groups G1 and G2 separated by a big gap (BG), the lens having a pop-out total track length TTL<20 mm in a pop-out state and a collapsed total track length c-TTL in a collapsed state, wherein BG>0.25TTL, wherein either G1 can move relative to G2 and to the image sensor for focusing or G1 and G2 can move together relative to the image sensor for focusing, and wherein a ratio c-TTL/TTL<0.7.

Pop-out lens systems for compact digital cameras, comprising an image sensor and a lens with a field of view FOV>60 deg and having i lens elements L1-Li starting with L1 from an object side toward an image side, each lens element Li having a respective focal length f.sub.i,, the lens elements divided into two lens groups G1 and G2 separated by a big gap (BG), the lens having a pop-out total track length TTL<20 mm in a pop-out state and a collapsed total track length c-TTL in a collapsed state, wherein BG>0.25TTL, wherein either G1 can move relative to G2 and to the image sensor for focusing or G1 and G2 can move together relative to the image sensor for focusing, and wherein a ratio c-TTL/TTL<0.7.

A lens barrel in which a lens can be moved in a direction parallel to an optical axis includes: a first frame having a cam follower and a cam follower base that holds the cam follower; and a second frame that has a cam groove engageable with the cam follower. The first frame and the second frame are moved relatively to each other along the optical axis. The cam follower base has a first end connected to the main body of the first frame via at least one thin portion, and a second end not connected to the main body. The thin portion is formed such that a thickness of the thin portion in a radial direction of the lens barrel is smaller than that of the cam follower base.

A lens barrel in which a lens can be moved in a direction parallel to an optical axis includes: a first frame having a cam follower and a cam follower base that holds the cam follower; and a second frame that has a cam groove engageable with the cam follower. The first frame and the second frame are moved relatively to each other along the optical axis. The cam follower base has a first end connected to the main body of the first frame via at least one thin portion, and a second end not connected to the main body. The thin portion is formed such that a thickness of the thin portion in a radial direction of the lens barrel is smaller than that of the cam follower base.

Pop-out lens systems for compact digital cameras, comprising an image sensor and a lens with a field of view FOV>60 deg and having i lens elements L1-Li starting with L1 from an object side toward an image side, each lens element Li having a respective focal length f.sub.i,, the lens elements divided into two lens groups G1 and G2 separated by a big gap (BG), the lens having a pop-out total track length TTL<20 mm in a pop-out state and a collapsed total track length c-TTL in a collapsed state, wherein BG>0.25TTL, wherein either G1 can move relative to G2 and to the image sensor for focusing or G1 and G2 can move together relative to the image sensor for focusing, and wherein a ratio c-TTL/TTL<0.7.

Pop-out lens systems for compact digital cameras, comprising an image sensor and a lens with a field of view FOV>60 deg and having i lens elements L1-Li starting with L1 from an object side toward an image side, each lens element Li having a respective focal length f.sub.i,, the lens elements divided into two lens groups G1 and G2 separated by a big gap (BG), the lens having a pop-out total track length TTL<20 mm in a pop-out state and a collapsed total track length c-TTL in a collapsed state, wherein BG>0.25TTL, wherein either G1 can move relative to G2 and to the image sensor for focusing or G1 and G2 can move together relative to the image sensor for focusing, and wherein a ratio c-TTL/TTL<0.7.

The imaging optical system consists of a first optical system and a second optical system along an optical path in order from an enlargement side to a reduction side. An intermediate image is formed between the first optical system and the second optical system. The imaging optical system satisfies a conditional expression of 1.73<tan m<5 regarding a maximum half angle of view m of the enlargement side. The imaging optical system satisfies predetermined conditional expressions regarding a curvature radius of an LA lens disposed adjacent to the reduction side of a longest lens spacing that is a longest spacing among spacings on an optical axis between lenses in the imaging optical system and a curvature radius of an LB lens disposed adjacent to the reduction side of the LA lens.

Pop-out lens systems for compact digital cameras, comprising an image sensor and a lens with a field of view FOV>60 deg and having i lens elements L1-Li starting with L1 from an object side toward an image side, each lens element Li having a respective focal length f.sub.i, the lens elements divided into two lens groups G1 and G2 separated by a big gap (BG), the lens having a pop-out total track length TTL<20 mm in a pop-out state and a collapsed total track length c-TTL in a collapsed state, wherein BG>0.25TTL, wherein either G1 can move relative to G2 and to the image sensor for focusing or G1 and G2 can move together relative to the image sensor for focusing, and wherein a ratio c-TTL/TTL<0.7.