Patent ID: 8804249

Claim:
A zoom lens comprising in order from an object side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a positive refractive power; and a fourth lens unit having a positive refractive power, wherein at the time of zooming, the first lens unit moves, and the zoom lens satisfies the following conditional expressions (1-1a), (1-2a), and (1-3a) 0.43<(β 2T /β 2W )/(β 3T /β 3W )<0.68 (1-1a) 0.4<(Δ 1G /f 1 )/(Δ 4G /f 4 )<2.3 (1-2a) 2.1 <f 3 /f W <4.1 (1-3a) where, β 2W denotes a lateral magnification at a wide angle end of the second lens unit, β 2T denotes a lateral magnification at a telephoto end of the second lens unit, β 3W denotes a lateral magnification at a wide angle end of the third lens unit, β 3T denotes a lateral magnification at a telephoto end of the third lens unit, Δ 1G denotes an amount of movement of the first lens unit at the time of zooming from the wide angle end to the telephoto end, Δ 4G denotes an amount of movement of the fourth lens unit at the time of zooming from the wide angle end to the telephoto end, f 1 denotes a focal length of the first lens unit, f 3 denotes a focal length of the third lens unit, f 4 denotes a focal length of the fourth lens unit, and f W denotes a focal length of the overall zoom lens system at the wide angle end.