I just got my X5 and have installed it correctly. I'm prompted to calibrate the lens...pointing it at a high contrast object 50m away...(160'). I'm assuming I need to be in auto focus mode to do this and that I should have the camera in a fixed, stable position on the ground? Is the 50 meters a critical distance, or do I just need to pick something out fairly far away for the calibration. Is there a message give indicating the calibration is successful? I was planning on shooting in manual focus mode...the manual says "always set the camera lens to AF mode." Not sure why the manual says to do this? Thanks for you help.