my friend's T4i makes a constant focus noise when autofocusing

[soccerballtux]

is this normal? it's like the servo is just bouncing between two focus settings

he doesn't seem very technically aka 'why it is doing what it is doing' inclined so I'm concerned that he may need to warranty it

 

[Nohr]

Is the auto focus set to AI Servo? That's for keeping focus on a moving subject. If the camera is in Full Auto mode (green A+ on the dial) it may be automatically switching AF to AI Servo if it detects the subject is moving. AI Focus will do this as well.

The AF setting for still subjects is One Shot. It'll focus just once and beep when it's focused. Have to take the camera out of Full Auto mode to change the AF settings however.

It also might bounce around trying to focus if it's too dark or if you're too close to the subject.

 

[EOM]

does the lens have IS turned on? My Nikon lens with VR is a bit loud sometimes with the VR turned on and active, even after i release the shutter/focus