The present application provides an optical lens
system, comprising: five lenses, the five lenses comprising a first lens to a fifth lens in sequence from an object side to an image side; a plurality of spacers, the plurality of spacers comprising a fourth spacer located on the image side of the fourth lens and in contact with the image side surface of the fourth lens; a lens
barrel for accommodating the lenses and the spacers; the
Abbe number V4 of the fourth lens and the
Abbe number V5 of the fifth lens satisfy: -40 < V4-V5 < -30; the effective
focal length f4 of the fourth lens, the effective
focal length f5 of the fifth lens, the inner
diameter d4s of the object side surface of the fourth spacer, the outer
diameter D4m of the image side surface of the fourth spacer satisfy: -1 < (d4s*D4m) / (f4-f5) < 3; the curvature
radius R7 of the object side surface of the fourth lens, the curvature
radius R8 of the image side surface of the fourth lens, the thickness CP4 of the fourth spacer, the air gap T45 of the fourth lens and the fifth lens on the
optical axis, the central thickness CT5 of the fifth lens satisfy: -40 < (R7+R8) / (CP4+T45+CT5) < -18. The present application solves the problem that the rear-
end system of the optical lens
system in the prior art is prone to
stray light.