Variable magnification optical system and imaging apparatus

A variable magnification optical system consisting of, in order from an object side:

• a first optical system that includes two reflecting mirrors having reflective surfaces arranged to face each other and remains stationary with respect to an image plane during changing magnification;
• and
• a second optical system that includes at least two positive lenses and at least one negative lens,
• wherein the two reflecting mirrors consist of
• a first reflecting mirror that has a reflective surface concave toward the object side and reflects light, which is originated from an object, toward the object side, and
• a second reflecting mirror that has a reflective surface convex toward an image side and reflects the reflected light, which is reflected from the first reflecting mirror, toward the image side,
• wherein the second optical system includes, successively in order from a position closest to the object side,
• a first lens group that consistently moves to the object side during changing magnification from a wide-angle end to a telephoto end and has a positive refractive power, and
• a second lens group that moves in a direction of an optical axis with a locus different from a locus of the first lens group during changing magnification and has a positive refractive power,
• wherein an intermediate image is formed between the second reflecting mirror and the first lens group, and the intermediate image is re-formed through the second optical system, and
• wherein assuming that
• an average value of partial dispersion ratios of all the positive lenses in the second optical system between a g line and an F line is θgFp, and
• an average value of partial dispersion ratios of all the negative lenses in the second optical system between the g line and the F line is θgFn,
• Conditional Expression (1) is satisfied,
• −0.04<θgFp−θgFn<0.1 (1).