Optical system and imaging apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorMakoto Nakahara
Life of this patent
Estimating the term…
Abstract
An optical system includes, in order from an object side toward an image side, a first lens unit having positive refractive power, and a second lens unit having negative refractive power. A distance between consecutive ones of the lens units changes when focusing is performed. The first lens unit is stationary during focusing. The second lens unit is moved toward the image side when focus is changed from an object at infinity to an object at a short distance. Lateral magnification β2 of the second lens unit when focusing on the object at infinity, focal length f1 of the first lens unit, and focal length f2 of the second lens unit are set appropriately to satisfy predetermined mathematical conditions.
Claims12
An optical system comprising, in order from an object side toward an image side:
- a first lens unit having positive refractive power;
- and
- a second lens unit having negative refractive power,
- wherein a distance between consecutive ones of the lens units changes when focusing is performed,
- wherein the first lens unit is stationary during focusing, and the second lens unit is moved toward the image side when focus is changed from an object at infinity to an object at a short distance, and
- wherein the optical system satisfies the following conditional expressions:
- 3.00<|1−β22|<8.00
- 0.20<|f1/f2|<0.59
- where β2 denotes lateral magnification of the second lens unit when focusing on the object at infinity, f1 denotes focal length of the first lens unit, and f2 denotes focal length of the second lens unit.
An imaging apparatus comprising:
- an optical system;
- and
- an imaging device configured to receive an image formed by the optical system,
- wherein the optical system comprises, in order from an object side toward an image side:
- a first lens unit having positive refractive power;
- and
- a second lens unit having negative refractive power,
- wherein a distance between consecutive ones of the lens units changes when focusing is performed,
- wherein the first lens unit is stationary during focusing, and the second lens unit is moved toward the image side when focus is changed from an object at infinity to an object at a short distance, and
- wherein the optical system satisfies the following conditional expressions:
- 3.00<|1−β22|<8.00
- 0.20<|f1/f2|<0.59
- where β2 denotes lateral magnification of the second lens unit when focusing on the object at infinity, f1 denotes focal length of the first lens unit, and f2 denotes focal length of the second lens unit.
Dependencies are inferred from the claim text.