Blurry 7D Group Photos
normally move the focus button off the shutter button by using Cfn settings.
Go into Auto focus and drive settings select number 2 AE Lock.
that will move your focus button to the asterick on the right side of the back of your camera.
During focus you will be able to focus with this button and hold it on the subject as you press the shutter also check your Aperture and make sure you are not shooting at too low a speed.