Patent ID: 8712232

Claim:
A real-image zoom viewfinder substantially consisting of, in order from an object side, a variable-magnification objective lens system having a positive refractive power, an erect optical system, and an eyepiece lens system having a positive refractive power, wherein the variable-magnification objective lens system substantially consisting of, in order from the object side, a first lens group that includes a first lens having a negative refractive power and a reflective member arranged in this order from the object side and is fixed during magnification change, a second lens group that has a positive refractive power and is moved during magnification change, and a third lens group that has a positive refractive power and is moved during magnification change, the erect optical system has at least one reflective surface for converting an inverted image formed by the variable-magnification objective lens system into an erect image and is fixed during magnification change, the eyepiece lens system has a positive refractive power and is fixed during magnification change, and conditional expressions (1), (2A) and (3) below are satisfied at the same time: 1.5 <U 2 /U 1<3.0 (1), 1.76 ≦|f 2 /f 1|<2.0 (2A) and 1.0 <f 3 /f 2<5.0 (3), where U1 is a distance from an object-side lens surface of the first lens to a most object-side lens surface in the second lens group along an optical axis in a state where zoom setting is set at a telephoto end, U2 is a difference between the distance from the object-side lens surface of the first lens to the most object-side lens surface in the second lens group along the optical axis in a state where the zoom setting is set at the telephoto end and a distance from the object-side lens surface of the first lens to a most image-side lens surface in the third lens group along the optical axis in a state where the zoom setting is set at a wide-angle end, f1 is a focal length of the first lens group, f2 is a focal length of the second lens group, and f3 is a focal length of the third lens group.