Abstract:
A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group. Upon zooming from the short to long focal length extremities, the distance between the first and second lens groups increases, and the distance between the second and third lens groups decreases. The following conditions are satisfied: 0.30
Abstract:
An imaging optical system includes a positive first lens element having a convex surface on the object side, a negative second lens element having a concave surface on the image side, a third lens element, a positive fourth lens element, a fifth lens element, and a negative sixth lens element provided with at least one aspherical surface that has inflection points other than at an optical axis thereof. The following conditions (1) and (2) are satisfied: 0.86
Abstract:
A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, each of the first through fourth lens groups move along the optical axis thereof. The following conditions (1) and (2) are satisfied: 1.05
Abstract:
An imaging optical system includes a positive first lens element having a convex surface on the object side, a negative second lens element having a concave surface on the image side, a third lens element, a positive fourth lens element, and a negative fifth lens element provided with at least one aspherical surface that has inflection points other than at an optical axis thereof. The following conditions (1) and (2) are satisfied: −0.80 60 (2), wherein r11 and r12 designate the radius of curvatures of surfaces on the object side and image side of the first lens element, respectively, and νd1 designates the Abbe number with respect to the d-line of the first lens element.
Abstract:
An objective optical system for information recording/reproducing, at least one of optical surfaces of the objective optical system comprising a diffraction surface including a first region contributing to converging first, second and third beams and including a diffraction structure formed such that use diffraction orders for the first, second and third beams are 1st-orders and a condition 0.03