Hi, I have an a700 and have loaned it to a friend of mine who was teaching english in Tunisia. She has been using a Sigma 70-300 and has noticed a great deal of blue fringing on her photos. She also gets a lot of red fringing when using the sony 70-300 but non on the sony 18-250. All the photos are taken in bright light and the Sigma is especially grainy. I can only hazard a guess that she may need to invest in better lenses. She also uses CS3. Any information would be greatly appreciated, Thanks.