i had recently brought a new XT1 yesterday and had updated with the latest firmware including my 14mm.... When i try to do a prefocus with half press the shutter button i notice there is some sound like spring compress sound coming out from the camera.... when i release the shutter button to exit from prefocus the sound came out again...

Is it normal ? I used before XE1 and XE2 with the same lens but never encounter the sound before....