Imaging lens including seven lenses of +−+0+−−,+−+0−+− or +−+0++− refractive powers

An imaging lens comprising in order from an object side to an image side,

• a first lens with positive refractive power having an object-side surface being convex in a paraxial region,
• a second lens with negative refractive power in a paraxial region,
• a third lens,
• a fourth lens being a double-sided aspheric lens,
• a fifth lens,
• a sixth lens having an image-side surface being concave in a paraxial region, and
• a seventh lens with negative refractive power having an image-side surface being concave in a paraxial region, wherein the image-side surface of said seventh lens is an aspheric surface having at least one pole point in a position off the optical axis, an image-side surface of said first lens is concave in a paraxial region, said third lens is formed in a meniscus shape in a paraxial region,
• an object-side surface and an image-side surface of said fourth lens are plane surfaces in a paraxial region, an image-side surface of said fifth lens is convex in a paraxial region, an object-side surface of said seventh lens is convex in a paraxial region, and the following conditional expressions (2) and (4) are satisfied:
• 1.80<νd3/νd5<4.00 (2)
• 10.00<νd4<29.00 (4)
• where
• νd3:
• an abbe number at d-ray of the third lens,
• νd5:
• an abbe number at d-ray of the fifth lens, and
• νd4:
• an abbe number at d-ray of the fourth lens.

An imaging lens comprising in order from an object side to an image side,

• a first lens with positive refractive power having an object-side surface being convex in a paraxial region,
• a second lens with negative refractive power in a paraxial region,
• a third lens,
• a fourth lens being a double-sided aspheric lens,
• a fifth lens,
• a sixth lens having an image-side surface being concave in a paraxial region, and
• a seventh lens with negative refractive power having an image-side surface being concave in a paraxial region, wherein the image-side surface of said seventh lens is an aspheric surface having at least one pole point in a position off the optical axis, an image-side surface of said first lens is concave in a paraxial region, said third lens is formed in a meniscus shape in a paraxial region,
• an image-side surface of said fifth lens is convex in a paraxial region, an object-side surface of said seventh lens is convex in a paraxial region, and the following conditional expressions (2), (4), and (9) are satisfied:
• 1.80<νd3/νd5<4.00 (2)
• 10.00<νd4<29.00 (4)
• 1.00<(T3/TTL)×100<4.00 (9)
• where
• νd3:
• an abbe number at d-ray of the third lens,
• νd5:
• an abbe number at d-ray of the fifth lens,
• νd4:
• an abbe number at d-ray of the fourth lens,
• T3:
• a distance along the optical axis from an image-side surface of the third lens to an object-side surface of the fourth lens, and
• TTL:
• a total track length.