Patent ID: 11940606
Assignee: CANON KABUSHIKI KAISHA
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 19:
20. An imaging apparatus comprising:
an optical system; and
an image sensor configured to receive an image formed by the optical system,
wherein the optical system includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a first focus lens unit having a negative refractive power, and a second focus lens unit having a positive refractive power,
wherein the first lens unit is fixed during focusing,
wherein the first focus lens unit and the second focus lens unit move so that a distance between the first focus lens unit and the second focus lens unit changes during focusing,
wherein the first lens unit includes a single lens which is disposed closest to an object and has a negative refractive power, and
wherein the following inequality is satisfied:

2.20<ff2/bf<12.00, where ff2 is a focal length of the second focus lens unit, and bf is a back focus of the optical system.