A projection lens disposed between a screen side and an image side and including a first lens group and a second lens group is provided. Refractive powers of the first lens group and the second lens group are respectively negative and positive. The first lens group includes a first lens, a second lens, and a third lens arranged in sequence from the screen side to the image side, and refractive powers thereof are respectively negative, negative, and positive. The second lens group is disposed between the first lens group and the image side and includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens arranged in sequence from the screen side to the image side, and refractive powers thereof are respectively positive, positive, negative, negative, negative, positive, and positive. A projection apparatus is provided.

A zoom lens includes a front unit having a negative refractive power and a rear unit having a positive refractive power, which includes an aperture stop, and the front unit includes a first lens having a negative refractive power, and the first lens has a meniscus shape of which a convex surface is directed toward the object side, and the rear unit includes a first lens unit A and a second lens unit B, and at the time of zooming from a wide angle end to a telephoto end, a distance between the front unit and the rear unit changes.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. A distance between adjacent lens units changes during zooming. The first lens unit includes two cemented lenses and each of the two cemented lenses includes a positive lens. Predetermined conditions are satisfied by the zoom lens.

A beam-shaping lens includes a first surface including a smooth-shaped concave surface; and a second surface including a convex surface substantially similar in shape to the concave surface. The beam-shaping lens converts a first light beam that is parallel light incident on the first surface and having a light intensity distribution that continuously increases from an outer periphery toward a center, into a second light beam that has a flatter light intensity distribution than that of the first light beam.

A zoom lens includes a first lens unit having negative refractive power and disposed closest to an object, and a rear group including three or more lens units and disposed on an image side of the first lens unit. A distance between adjacent lens units changes during zooming. The first lens unit moves toward the image side during zooming from a wide-angle end to a telephoto end. Predetermined inequalities are satisfied.

A zoom lens is provided which has a wide angle of view and is bright and in which the entire lens system is compact and which can achieve high optical characteristic over the entire zoom range.

A zoom lens includes, in order from an object side to an image side: a first lens unit having a negative refractive power; and a second lens unit having a positive refractive power, the interval between the adjacent lens units varying during zooming. The configuration of the first lens unit, the focal length f1 of the first lens unit, and the back focus Sk at the wide angle end are appropriately set.

A zoom lens arranged along an optical axis includes a first lens group and a second lens group. The second lens group has at least one aspheric lens. The first lens group moves toward an image side and the second lens group moves away from the image side along the optical axis during zooming. The first lens group is moved for focusing, and the second lens group is moved for zooming.

A zoom lens including a first lens group and a second lens group is provided. Refractive powers of the first lens group and the second lens group are respectively negative and positive. The first lens group includes a first lens, a second lens, and a third lens arranged in sequence from an object side to an image side. The second lens group is disposed between the first lens group and the image side, and includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in sequence from the object side to the image side. The zoom lens satisfies 2.4<f1/f.sub.w<1.0, wherein f1 is the effective focal length of the first lens group, and f.sub.w is the effective focal length of the zoom lens at a wide end.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, and a rear unit having a positive refractive power as a whole. A distance between the first lens unit and the rear unit is changed during zooming. The rear unit includes a subunit that is moved in a direction having a component of a direction orthogonal to an optical axis during image stabilization. The first lens unit includes, in order from the object side to the image side, three or more negative lenses. A predetermined condition is satisfied.