I have been photographing more and more real estate and needed a lens that could help me capture everything in a room without cutting anything out, complete ceiling to floor, wall to wall action. So I borrowed the Sigma 10-20mm lens from Borrowlenses.com for only $29 for 3 days! Here is a quick comparison with my iPhone vs the Sigma:

My cell phone photo

Photo using the Sigma

Now you can tell just by comparison that the Sigma completely blew my iPhone out of the water. The whole kitchen, living room and bedroom were captured in one shot. The ultimate benefit of using a wide angle lens with real estate photography is to be able to fit into tight spaces, capture everything in the room and also give the illusion that the space is a little larger than it actually is. Being able to show both the floor and the ceiling helps with this. If you need a cheap, high quality wide angle lens I would highly suggest the Sigma 10-20mm.