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US 2006/0077569 A1Published application
Lens system and optical device having the same
AssigneeCanon Kabushiki Kaisha
InventorAkira Harada
Life of this patent
Estimating the term…
Abstract
A lens system has a plurality of lenses, a stop, and a diffractive surface, the entire lens system moves during focusing, and the lens system satisfies the condition of β≧0.5, where β is a maximum photographic magnification.
Claims13
1-27. (canceled)
A lens system comprising;
- a diffractive surface, and
- a first lens unit of a positive optical power, a second lens unit of a negative optical power disposed on the image side of said first lens unit, and a third lens unit of a positive optical power disposed on the image side of said second lens unit,
- wherein during focusing from an object at infinity to an object at a near distance, said first lens unit is fixed, said second lens unit moves toward an image side, and said third lens unit moves toward the object side, and
- wherein the following condition is satisfied by said lens system:
- |β|≧0.5,
- where β is a maximum photographic magnification.
3 more elements
(canceled)
37-55. (canceled)
57-58. (canceled)
Dependencies are inferred from the claim text.