PURPOSE: To provide a compact photographic lens with large aperture which is excellent in drawing property by specifying the space on the optical axis between the first lens from a subject side and the second lens, the core thickness of the third lens from the subject side, and the synthetic refraction force of the whole group.
CONSTITUTION: A photographic lens is divided into a front group and a rear group from a subject side, the front group consists of a positive lens, a negative lens, and both convex lenses, and the rear group consists of at least one positive lens and a negative meniscus lens whose convex surface is turned on the image side, and satisfying the conditions of the expressions I-III. In the expressions I-III, D2 is the space on the optical axis between the first lens from the subject side and the second lens; D5 is the core thickness of the third lens from the subject side; (f) is the focus distance of the whole system; F is the synthetic reflection force of the front group; is the refraction force of the whole system. Thus, a compact photographic lens with large aperture (F-number is about 1.7) having good drawing property can be provided.
| WO/2013/003276 | OPTICAL ARRANGEMENTS FOR USE WITH AN ARRAY CAMERA |
| JPS5451826 | PHOTOGRAPHIC LENS |
OSAWA SATOSHI
OKUDAIRA SADAO
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