Patent ID: 7715114

Claim:
A zoom lens, comprising: a first lens group having a positive refracting power; a second lens group having a negative refracting power; a third lens group having a positive refracting power; and a fourth lens group having a positive refracting power; said first, second, third and fourth lens groups being disposed in order from the object side; upon zooming from the wide-angle end to the telephoto end, said first lens group moving so as to increase the distance to said second lens group, said second lens group moving to the image side once and then moving so as to return to the object side, and said third lens group moving to the object side; said first lens group including only a cemented lens including a positive lens, and a negative lens; said positive lens and said negative lens being cemented in order from the object side; said cemented lens having a generally positive refracting power; said first lens group being configured so as to satisfy the following conditional expression (1): 25<ν d11 −ν d12 <50 (1) where ν d11 is the Abbe number of said positive lens of said first lens group and ν d12 is the Abbe number of said negative lens of said first lens group.