Wide-angle zoom lens

A wide-angle zoom lens comprising:

• a first lens group having a positive refracting power and a second lens group having a negative refracting power, which are moved relative to each other along an optical axis so as to attain zooming, a lens in the first lens group which is closest to the object side having a convex surface facing the object side,
• said first lens group being constituted in turn from the object side by a front group having a negative refracting power and a rear group having a positive refracting power, and being constructed so that the spacing between the front group and the rear group is constant during zooming,
• said front group having at least one negative lens,
• said rear group having at least two positive lenses, and
• said zoom lens being constituted to satisfy the following conditions:
• 0.1<D.sub.2 /f.sub.W <0.4
• 0.2<D.sub.3 /f.sub.W <0.4
• 0.75<.vertline.f.sub.F /f.sub.W .vertline.<4;
• f.sub.F <0
• where f.sub.F is the focal length of said front group in said first lens group, f.sub.W is the focal length of said zoom lens at the wide-angle end, D.sub.2 is the axial distance from a lens surface at the extreme image-side end in said front group to a lens surface at the extreme object-side end in said rear group in said first lens group, and D.sub.3 is the central thickness of said positive lens at the extreme object-side end in said rear group in said first lens group.

A wide-angle zoom lens consisting of:

• a first lens group having a positive refracting power and a second lens group having a negative refracting power, which are moved relative to each other along an optical axis so as to attain zooming,
• said first lens group being provided with a lens surface convex to the object side and positioned nearest the object side, and being constituted in turn from the object side by a front group having a negative refracting power and a rear group having a positive refracting power, and being constructed so that the spacing between said front group and said rear group is constant during zooming,
• said front group having at least one negative lens,
• said rear group having at least two positive lenses, and
• said zoom lens being constituted to satisfy the following condition:
• 0.1<K/f.sub.W <0.4
• where f.sub.W is the focal length of said zoom lens at the wide-angle end, and K is the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction.