Hi, I have a Sony A33 camera body and I am looking to upgrade from my Sony 18-55mm lens. I was told that I could buy an adapter and use the Sigma 28-105mm f2.8-4 lens. Any suggestions on if this would be a good purchase? Would I lose quality? Do you know of a better lens at an affordable price?I am using it for basic music video production and photography. Thanks in advance!