Zoom lens and photographing apparatus including the same

A zoom lens comprising:

• a first lens group having a positive refractive power;
• a second lens group having a negative refractive power;
• a third lens group having a positive refractive power;
• a fourth lens group having a negative refractive power;
• and
• a fifth lens group having a positive refractive power,
• wherein the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group are arranged sequentially from an object side to an image side of the zoom lens,
• wherein the first lens group comprises a doublet lens and a lens having a positive refractive power,
• wherein the second lens group comprises a first sub-lens group having a negative refractive power and a second sub-lens group having a negative refractive power that is arranged to perform a focusing function,
• wherein each of the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group is arranged to move when the zoom lens is zoomed, and
• wherein the zoom lens satisfies the following condition:
• 0.4<BFw/FLw<1.1,
• where FLw denotes a total focal length of the zoom lens when the zoom lens is in a wide-angle mode and BFw denotes a back focal length of the zoom lens when the zoom lens is in the wide-angle mode.