To provide sufficient back focus and peripheral light quantity and to reduce coma flare, the curvature of field and chromatic aberration to obtain high image forming performance.
This lens is constituted of 1st and 2nd lenses L1 and L2 having positive refractive power, a 3rd lens L3 having negative refractive power, a 4th lens L4 having the negative refractive power and a 5th lens L5 having the positive refractive power which are bonded each other, and a 6th lens L6 having the positive refractive power in order from an object side. When it is assumed that Σd is the distance from the 1st surface to the final surface, (f) is the focal distance of a lens system, di is the distance between each surface of the successive lenses from the object side and ri is the radius of curvature of each surface of the successive lenses from the object side, the lens satisfies conditions; (1) 0.35<Σd/f<0.51, (2) 0.30<(d6+d7)<Σd<0.55, (3) 0.14<(r5-r4)/(r5+r4)<0.42.
Next Patent: SHIFT TILT LENS