Imaging lens system

The invention provides a way to maintain the optical performance and are able to achieve small lightweight and camera lenses to improve manufacturing efficiency. From the side of the camera lens in turn equipped with convex head for Coke-side of the bump 1th 3 lens 2, aperture of the lens, convex bump on the imaging side 2nd lens 4. Its meet following the conditions type, 1.25xf1 ≥ l ≥ 0.8xf1, and 1.26xf1 ≥ F1 ≥ 0.85xf1, and 0.8xd1 ≥ D2 ≥ 0.35xd1, and l ≤ 6.25mm, and D1 ≥ 0.225xf1, and D3 ≥ 0.225xf1 (l for lens system of full length, F1 for lens system overall of focal length, F1 for 1th lens 2 of focal length, D1 for 1th lens of Center thickness, D2 for 1th, and 2nd lens Zhijian of interval, D3 as the 2nd Center thickness of lens).