A lens system comprising a first lens group with a negative refractive power,
a
second lens group with a positive refractive power, and a third lens group with
a positive refractive power arranged in this order from an object side, wherein
a focal length f2 of the second lens group, a focal length f3 of
the third lens group and a radius of curvature Rm of an object side-surface of
a lens that is closest to the object side in the second lens group satisfy following conditions
0.30Rm/f20.45
0.8f2/f31.2.
The present invention provides a lens system with favorable telemetric characteristics
for a digital camera and a sufficient aberration performance using a total of just
seven lenses without using an aspherical lens.
