| 摘要 |
PURPOSE: To provide a wide-angle, high-magnification and highresolution zoom lens composed of a few lenses by adopting optimum lens configuration and optimum non-spherical form. CONSTITUTION: This zoom lens is composed of a first lens group 1 of a fixed group composed of a negative refracting power lens, positive refracting power lens and meniscus positive refracting power lens successively from the side of an object, second lens group 2 provided with non-spherical faces more than one at least and composed of a negative refracting power lens, both-face concave lens of negative refracting power and positive refracting power lens in order to take the charge of a magnifying operation while moving, third lens group 3 of a fixed group provided with positive refracting power including one non-spherical face at least, and fourth lens group 4 provided with non- spherical faces more than one at least so as to move while following up magnification and physical point movements. When a wide angle end field focal distance is defined as fw, an image angle at the wide angle end is defined asω, the focal distance of the first lens group is defined as f1 and the focal distance of the second lens group is defined as f2, this video camera satisfies an expression as follows; 0.1<(fw.tanω)/(f1.|f2|)<1/2> <0.35.
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