Is my Lens having Focusing Problems? Front Focus?

[Cpalmer03]

Hey everyone! I just bought a new lens for my T1i, it is a Sigma 24-70mm F2.8 but I am wondering if the lens is having trouble focusing or it is operator error. I am only having focus problems @ F2.8 and at 24mm. When zoomed in, all focus works perfectly. Great focus at F4.5

Check out these images I took to test focal plane.
Trying to focus on the golf ball @ 24mm and 48mm

24mm


48mm


Trying to focus on the golf ball. (But focus is on the front battery)


Here were some other focus issues I was having...
Switching focus from battery to lego...twice, when i focus on lego it is out of focus, but when i focus on battery it is in focus.



Any help would be great. Thanks.