Patent ID: 11960066
Assignee: CANON KABUSHIKI KAISHA
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 12:
13. An apparatus comprising:
a zoom lens; and
a sensor configured to receive an optical image formed by the zoom lens,
wherein the zoom lens includes four or more lens units including, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a positive refractive power,
wherein a distance between adjacent lens units varies during zooming from a wide-angle end to a telephoto end,
wherein the first lens unit moves during zooming,
wherein a distance between the first lens unit and the second lens unit widens during zooming from the wide-angle end to the telephoto end,
wherein a distance between the second lens unit and the third lens unit narrows during zooming from the wide-angle end to the telephoto end,
wherein the first lens unit consists of three or less lenses,
wherein the second lens unit consists of, in order from the object side to the image side, a first single lens as a spherical lens having a negative refractive power, a cemented lens in which a lens having a negative refractive power and a lens having a positive refractive power are cemented, and a second single lens as a spherical lens having a negative refractive power, and
wherein following inequalities are satisfied:

1.35≤|f2|/skm≤5.00

3.1≤d21/d22≤6.0

48≤νBC≤80

3.5≤|f1/fw|≤10.0

where skm represents a minimum value of a back focus in an entire zoom area of the zoom lens, f2 represents a focal length of the second lens unit, d21 represents a distance on an optical axis between a lens surface on the image side of the first single lens and a lens surface on a most object side of the cemented lens, and d22 represents a distance on the optical axis between a lens surface on a most image side of the cemented lens and a lens surface on the object side of the second single lens, and νBC represents an average value of an Abbe numbers for a d-line, f1 represents a focal length of the first lens unit, and fw represents a focal length of the zoom lens at the wide-angle end.