Imaging optical system and image pickup apparatus using the same
First Claim
1. An imaging optical system comprising in order from an object side thereof:
- a front lens unit having a negative refracting power;
an aperture stop; and
a rear lens unit having a positive refracting power, whereinthe front lens unit having a negative refracting power includes in order from the object side, a first lens having a negative refracting power, andthe rear lens unit having a positive refracting power includes in order from the object side, a second lens which is a positive lens, a third lens which is a negative lens, and a fourth lens which is a positive lens, andthe imaging optical system satisfies the following conditional expressions (1) and (2)
1.6<
|fG1|/FA<
5
(1)
1.2<
fG2/FA<
5
(2)where,FA denotes a focal length of the overall imaging optical system,fG1 denotes a focal length of the front lens unit having a negative refracting power, andfG2 denotes a focal length of the rear lens unit having a positive refracting power.
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Accused Products
Abstract
An imaging optical system includes in order from an object side thereof: a front lens unit having a negative refracting power, an aperture stop, and a rear lens unit having a positive refracting power. The front lens unit includes in order from the object side, a first lens having a negative refracting power. The rear lens unit includes in order from the object side, a second lens which is a positive lens, a third lens which is a negative lens, and a fourth lens which is a positive lens. The imaging optical system satisfies conditional expressions (1) and (2): 1.6<|fG1|/FA<5 . . . (1); 1.2<fG2/FA<5 . . . (2); where FA denotes a focal length of the overall imaging optical system, fG1 denotes a focal length of the front lens unit, and fG2 denotes a focal length of the rear lens unit.
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Citations
13 Claims
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1. An imaging optical system comprising in order from an object side thereof:
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a front lens unit having a negative refracting power; an aperture stop; and a rear lens unit having a positive refracting power, wherein the front lens unit having a negative refracting power includes in order from the object side, a first lens having a negative refracting power, and the rear lens unit having a positive refracting power includes in order from the object side, a second lens which is a positive lens, a third lens which is a negative lens, and a fourth lens which is a positive lens, and the imaging optical system satisfies the following conditional expressions (1) and (2)
1.6<
|fG1|/FA<
5
(1)
1.2<
fG2/FA<
5
(2)where, FA denotes a focal length of the overall imaging optical system, fG1 denotes a focal length of the front lens unit having a negative refracting power, and fG2 denotes a focal length of the rear lens unit having a positive refracting power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An imaging optical system comprising in order from an object side thereof:
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a front lens unit having a negative refracting power; and a rear lens unit having a positive refracting power, wherein the first lens unit having a negative refracting power includes in order from the object side, a first lens having a negative refracting power, and the rear lens unit having a positive refracting power includes in order from the object side, a second lens which is a positive lens, a third lens which is a negative lens, and a fourth lens which is a positive lens, and an aperture stop which determines an F number is provided between the front lens unit and the rear lens unit, and the F number is 1.8 or less. - View Dependent Claims (11, 12, 13)
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Specification