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US 2011/0234882 A1Published application
Image forming optical system and electronic image pickup apparatus using the same
AssigneeOlympus Corporation
InventorsKanato Adachi, Takayuki Mimura
Life of this patent
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Abstract
In an image forming optical system which includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power, a refractive index for a d-line of a positive single lens having the largest refractive power among all lenses in the second lens group, is the smallest of a refractive index of lenses in the second lens group.
Claims8
An image forming optical system comprising in order from an object side:
- a first lens group having a positive refractive power;
- a second lens group having a negative refractive power;
- a third lens group having a positive refractive power;
- and
- a fourth lens group having a positive refractive power, wherein
- a refractive index for a d-line of a positive single lens having the largest refractive power among all lenses in the second lens group, is the smallest among all lenses in the second lens group.
3 more elements
Dependencies are inferred from the claim text.