the present invention spherical aberration remains in a position between the wide angle end and the intermediate focal length in order to perfectly correct the aberration it is preferable that the second lens group is composed of three groups of three lens pieces the third lens group is provided with an aspherical surface or the fourth lens group is provided with an aspherical surface the values of conditions 1 and 2 are as follows in each example ______________________________________ example 1 example 2 example 3 example 4______________________________________condition 1 0 04 0 00 0 09 0 00condition 2 1 33 1 33 1 32 1 33______________________________________ in the following tables r is a radius of curvature of each lens surface d is a central lens thickness or a lens interval n is a refractive index of glass v is an abbe 39 s number f is a focal length of the entire lens system 2 u03c9 is an angle of view fno is an f number y is a maximum image height and a b c d and e represent the moving distance of each lens group at the wide angle end intermediate focal length and telescopic end wherein the object distance is 1 m in a focusing operation in these examples a glass block corresponding to bk7 is disposed behind the fifth lens group and this glass block was assumed to be a filter when the lens system was designed ______________________________________example 1f 4 63 54 80 fno 1 85 2 262 u03c9 69 69 u00b0 6 22 u00b0 y 3 03surface no r d n u03bd______________________________________ 1 57 648 0 80 1 80518 25 4 2 24 840.