| 摘要 |
A wide angle lens system of an inverted telephoto type is provided. The lens system comprises six separate lens groups comprising, consecutively from the object to the image side a negative meniscus lens element; a positive doublet; a positive meniscus lens element; a biconcave single lens element; a positive lens element and a rear positive lens element. One of the lens elements of the fifth and sixth groups is a single lens element while the other is a doublet. The lens is capable of providing an aperture ratio greater than F/2.0, a field angle of approximately 64 degrees and a back focal distance greater than the focal length of the system.
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