Auto Focusing should be more of a difference of lighting conditions, and how the image lines up with the autofocus points.


Manual focusing is all of you []


The depth of the focus will depend on distance and aperture settings, which depend on your position and the camera setting, which controls the aperture of the lens.


There's not much to control the lense with the exception of IS.


Auto Focus/Manual focus should be pretty self explanatory. Unless your camera is in AI servo mode, you can always override the initial autofocus with the focus ring.


Image Stabilization on/off. Image stabilization helps the lens hold steady optically. It's very visible through the viewfinder, if you turn it on or off. It's really handy, though it can have a startup jump to position that may mean you want it off if you're taking quick shots and have plenty of light for fast exposures anyway.


Mode 1 is image stabilization for stationary shooting. You press the camera picture taking button down halfway to engage the image stabiliztion and autofocus. When you've got what you want squeeze.


mode 2 is for panning, following a moving object. You press the button down (and probably have AI servo auto focus on), and squeeze when you want your shots.


That's really all there is to it, in terms of lens controls, I think.