| 摘要 |
PURPOSE:To reduce the size over the entire system by constituting a converter lens of the 1st lens of negative refracting power and the 2nd lens of positive refracting power successively from the object side and forming these lenses in such a manner that the refracting powers thereof satisfy the prescribed conditions. CONSTITUTION:This lens is the converter lens C of negative refracting power which is mounted on the image face side of a main lens system S to change the focal length of the entire system. Such converter lens C is constituted, successively from the object side, of the two lenses; the 1st lens of negative refracting power and the 2nd lens of positive refracting power and is so constituted as to satisfy the conditions expressed by equation when the refracting powers of the glass of the 1st and 2nd lenses are respectively designated as N1, N2. The size over the entire part of the lens is thereby reduced and the converter lens C having good optical performance is obtd.
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