Freezing Issue with my XSI

this has happened before, but recently seemed to get a little worse.

Out of no where, the camera kinda freezes, i can't shoot nor focus. i can't even shoot if i put it on manual focus. the only way to fix it is to turn it off for a couple seconds and turn it back on. but recently it took longer for the camera to come back to normal state.

is this a common thing or?

Im using a Sigma 17-70 OS 2.8-4 and a opteka grip (camera doesnt work if i use the shutter button on the grip or the camera)

am i the only one having this issue?

redfire2002 wrote in post #10564870
am i the only one having this issue?

That appened on my xsi too a couple times,the only solution was taking off the battery.
I think it was something to do with the lens.