Patent ID: 7405886

Claim:
A zoom lens device comprising, from an object side to an image side: a negative first lens group; a positive second lens group; and a positive third lens group; with no intervening lenses between the first second and third lens groups; and wherein the second lens group comprises four lenses having a closest-to-object-side lens having an object-side surface that is aspheric and a closest-to-image-side lens having an image-side surface that is aspheric; wherein the second lens group has an overall focal length f G2 and the closest-to-image-side lens of the second lens group has a focus length f L6 , which satisfy the following condition: 2.10 ≤ f L ⁢ ⁢ 6 f G ⁢ ⁢ 2 ≤ 3.20 ; ⁢ and wherein when the zoom lens device varies from a wide-angle condition to a telephoto condition, the second lens group moves towards the object side while the first lens group moves firstly towards the imaging side and then towards the object side, so that the distance between the first and second lens groups is shortened.