| 摘要 |
PURPOSE:To set up a zoom ratio to about three times and to reduce the variation of aberration by constituting a relay lens system satisfying specific conditions by a front group consisting of two positive convex meniscus lenses and a negative lens on the object side and rear group consisting of a negative convex meniscus lens and a positive lens on the image side. CONSTITUTION:The relay lens system R is constituted of the front, group IVconsisting of two positive convex meniscus lenses and the negative lens on the object side and the rear group V consisting of the negative convex meniscus lens and the positive lens on the image side and satisfies the following conditions. (1) 0.7<f4/fR<0.85, (2) 0.9<phi4s.fR<1.7, (3) 30<nu4n, (4) 40<nu5p, (5) 0.167< f4p1/f4p2<6.0, (6) 1.7<(n4n+n5n)/2<1.9. Provided that fR is the focal distance of R, F4 is the focal distance of the front group IV of the R, f4p1, f4p2 are the focal distances of the positive lenses of the object and image sides of the front group IV respectively, phi4s is the 1st side power of the positive lens of the front group IV, n4n, n5n are refractive indexes of the negative lens of the front group and the negative lens of the rear group repectively, nu4p, nu5p are Abbe numbers of the negative lenses of the front group IV and rear group V in R respectively. |
