Fixed focal length lens and image pickup apparatus
AssigneeCanon Kabushiki Kaisha
InventorsAkihiko Yuki, Shohei Kikuchi
Life of this patent
Estimating the term…
Abstract
A fixed focal length lens including, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit and a third lens unit, wherein the first lens unit does not move for focusing, at least the second lens unit moves for focusing, a distance between each pair of adjacent lens units changes for focusing, and the first lens unit includes two negative lenses disposed in succession from the object side, and wherein a focal length of the fixed focal length lens, a focal length of the first lens unit, and a combined focal length of the two negative lenses of the first lens unit are appropriately set.
Claims10
A fixed focal length lens comprising, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit, and a third lens unit, wherein the first lens unit does not move for focusing, at least the second lens unit moves for focusing, a distance between each pair of adjacent lens units changes for focusing, and the first lens unit includes two negative lenses disposed in succession from the object side, and wherein
- conditional expressions
- 1.0<f1/f<6.5, and
- 0.05<|f1n|/f1<0.22
- are satisfied where f represents a focal length of the fixed focal length lens, f1 represents a focal length of the first lens unit, and f1n represents a combined focal length of the two negative lenses of the first lens unit.
An image pickup apparatus comprising:
- a fixed focal length lens comprising, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit, and a third lens unit, wherein the first lens unit does not move for focusing, at least the second lens unit moves for focusing, a distance between each pair of adjacent lens units changes for focusing, and the first lens unit includes two negative lenses disposed in succession from the object side, and wherein
- conditional expressions
- 1.0<f1/f<6.5, and
- 0.05<|f1n|/f1<0.22
- are satisfied where f represents a focal length of the fixed focal length lens, f1 represents a focal length of the first lens unit, and f1n represents a combined focal length of the two negative lenses of the first lens unit, and
- an image pickup element arranged on an image plane of the fixed focal length lens.
Dependencies are inferred from the claim text.