| 摘要 |
PROBLEM TO BE SOLVED: To provide a photographic lens with four lens groups as a whole, and provided with a good optical performance within an extent from unmagnification to five-power as for photographing magnification by making a good use of a floating effect. SOLUTION: The photographic lens is constituted of a 1st lens group L1 whose refractive power is positive, a 2nd lens group L2 whose refractive power is positive, a 3rd lens group L3 whose refractive power is negative and a 4th lens group L4 whose refractive power is negative in order from an object side, and in accordance with the increase of the photographing magnification, the 1st lens group L1, the 2nd lens group L2 and the 3rd lens group L3 are moved toward the object side with reference to the image field.
|
