Hi, I am quite interesting in buying the Sigma 24-70mm DG EX HSM lens (for Canon). I tested one which belong to a friend and I noticed it blurs a little bit the right side at 70mm. So wanted to know if it is a particular behavior to the lens I tested or if it is a lens fault? Since I do panoramic and high-definition images, this detail is important for me. If someone owns this lens, please give me your opinion of this. Thanks.