Zoom lens and image capturing apparatus

An inner focus type zoom lens comprising:

• a first lens group that has positive refracting power and is normally located at a fixed position, a second lens group that has negative refracting power and is movable in an optical axis direction for zooming, a third lens group that has positive refracting power, and a fourth lens group that is movable for correction of a focal position due to the zooming and for focusing, in order from an object side,
• wherein the first lens group includes a negative lens, a first positive lens, and a second positive lens arranged in order from the object side,
• wherein a first face of the negative lens has a shape of a concave surface turned on the object side, and
• wherein the zoom lens satisfies the following conditional equation (1):
• (1) −10.0<G1R1/fw<−3.0, where G1R1 is a curvature radius of a lens surface closest to the object side, and fw is a focal length of the overall lens system at the wide-angle end.

An image capturing apparatus comprising:

• a zoom lens that includes a plurality of lens groups and performs zooming by varying distances between the plurality of lens groups;
• and
• an imaging device that converts an optical image formed by the zoom lens into an electric signal,
• wherein the zoom lens is an inner focus type zoom lens including a first lens group that has positive refracting power and is normally located at a fixed position, a second lens group that has negative refracting power and is movable in an optical axis direction for zooming, a third lens group that has positive refracting power, a fourth lens group that is movable for correction of a focal position due to the zooming and for focusing, and a fifth lens group that has positive refracting power, in order from an object side,
• wherein the first lens group includes a negative lens, a first positive lens, and a second positive lens arranged in order from the object side,
• wherein a first face of the negative lens has a shape of a concave surface turned on the object side, and
• wherein the zoom lens satisfies the following conditional equation (1):
• (1) −10.0<G1R1/fw<−3.0, where G1R1 is a curvature radius of a lens surface closest to the object side, and fw is a focal length of the overall lens system at the wide-angle end.