when i was cleaning my mirror by blowing the dust off with the hand pump blower, i've experienced shutter problem right afer. the first 2 shots i took on my 5d2, on the display i have noticed dark bar all the way on the side, looks like shutter curtain. after changing the shutter speed it went away and it has been good since. i got a little scarred. maybe next time i should send it in to canon for cleaning. is this bad?? the camera has about 5k clicks. i still have one little tiny spot showing up in my pictures that i can't remove.