Variable magnification optical system and imaging apparatus

A variable magnification optical system consisting of, in order from an object side to an image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, an intermediate group, and a final lens group having a refractive power,

• wherein the intermediate group consists of two or more and five or fewer lens groups,
• during changing magnification, a spacing between the first lens group and the second lens group changes, a spacing between the second lens group and the intermediate group changes, a spacing between the intermediate group and the final lens group changes, and all spacings between adjacent lens groups in the intermediate group change, and
• in a case where a back focus of the variable magnification optical system as an air conversion distance at a wide angle end is denoted by Bfw,
• a focal length of the variable magnification optical system in a state where an infinite distance object is in focus at a telephoto end is denoted by ft, and
• a maximum half angle of view in the state where the infinite distance object is in focus at the telephoto end is denoted by ωt,
• Conditional Expression (1) is satisfied, which is represented by
• 0.4
• <
• Bfw
• /
• (
• ft
• ×
• tan
• ⁢
• ω
• ⁢
• t
• )
• <
• 1.7
• .
• (
• 1
• )