Wide angle lens arrangement has negative and positive lens groups, with a specific ratio of focal lengths of negative lens group to overall arrangement

摘要

The wide angle lens arrangement has a negative first lens group (10) and a positive second lens group (20) to which an aperture is attached in sequence from the object side. The focal length f1 of the first lens group and the focal length f of the overall optical arrangement fulfill the relationship that the ratio of f1/f is greater than -1.4 and less than - 1.1.