Optical: systems and elements – Lens – Selective magnification by exchanging or adding a lens...
Patent
1993-12-01
1996-01-02
Epps, Georgia Y.
Optical: systems and elements
Lens
Selective magnification by exchanging or adding a lens...
G02B 1502
Patent
active
054814049
ABSTRACT:
A zoom lens having a super wide angle has a first lens group having positive refracting power and arranged on an object side of the zoom lens; a second lens group having negative refracting power and arranged on an image side of the zoom lens; and a converter lens having positive refracting power and detachably attached between the first and second lens groups. A focal length of the zoom lens is changed by changing a distance between the first and second lens groups. The distance between the first and second lens groups is set to be wide on a wide angle side in a zooming region and narrow on a telescopic side in the zooming region. The focal length of the zoom lens at the super wide angle is set to be shorter than that at a wide angle end in the zooming region by mounting the converter lens on the wide angle side. In accordance with this structure, the super wide angle at a focal length shorter than that at a normal wide angle can be realized by adding the converter lens to the zoom lens composed of the first positive lens group and the second negative lens group without substantially increasing an entire length of the zoom lens.
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Epps Georgia Y.
Lester Evelyn A.
Ricoh & Company, Ltd.
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