a lens system and a for a capsule endoscope includes a first lens having a concave aspheric surface having a radius r2 and a second lens having a convex aspheric surface having a radius r3 facing the first lens . a third lens has a convex aspheric surface having radius r6 . the lens system satisfies the following conditions : r2 / gap & gt ; 1 and abs & gt ; 1 . 28 ; 1 & lt ; abs & lt ; 1 . 1 and r6 & lt ; 0 ; and v2 & lt ; v1 and v2 & lt ; v3 ; wherein : i ) gap is a distance from a center of curvature of the concave aspheric surface of the first lens to a center of curvature of the convex aspheric surface of the second lens ; abs denotes absolute value ; and v1 is an abbe number of the first lens , v2 is an abbe number of the second lens , and v3 is an abbe number of the third lens .