Abstract:
An imaging optical system includes a first lens group having positive power, a second lens group, and a third lens group. The first lens group includes a sub-lens group G1A, an aperture stop, and a sub-lens group G1B. The sub-lens group G1A includes a lens L1A1 and a lens L1A2. An object-side surface of the lens L1A1 is convex toward an object. The third lens group includes a lens L3E having negative power and a lens L3P located adjacent to, and closer to the object than, the lens L3E.
Abstract:
A single focal length lens system includes, in order from an object side to an image side, a first lens unit having positive optical power and a second lens unit including a lens element that moves in a direction of an optical axis with respect to an image surface in focusing from an infinity in-focus condition to a close-object in-focus condition. The first lens unit includes an aperture diaphragm and a lens element A located on the object side of the aperture diaphragm. A lens element B having positive optical power and a lens element C having negative optical power are located on the image side of the aperture diaphragm. Abbe numbers of the lens elements A, B, and C to the d-line and partial dispersion ratios of the lens elements A, B, and C for the g-line and the F-line satisfy a predetermined relation.
Abstract:
An imaging optical system includes: a front group having positive power; an aperture stop; a single lens Fn arranged adjacent to the aperture stop and having negative power; and a rear group having power. The front group includes: a first lens having positive power; a second lens having negative power; and a lens LG1R having positive power. The rear group includes a lens LGnR having negative power and located closest to the image. While focusing to make a transition from an infinity in-focus state to a close-object in-focus state, neither the front group nor the rear group moves but the single lens Fn moves along an optical axis toward the image. The imaging optical system satisfies the inequality: 0.38
Abstract:
An imaging optical system, in order from an object side to an image side, includes: a first lens unit having positive optical power; and a second lens unit. In focusing from an infinity in-focus condition to a close-object in-focus condition, the first lens unit moves along an optical axis, and the second lens unit is fixed with respect to an image surface. The imaging optical system is compact, sufficiently suppresses occurrence of various aberrations, has high resolution from the infinity in-focus condition to the close-object in-focus condition, is bright and highly efficient, and is suitable for wide-angle photographing.