I have recently bought a second hand Canon 100-400 IS L zoom lens which I am extremely pleased with. However, there was no manual with the lens and I am cannot figure out through use, the difference between Mode 1 and Mode 2 in terms of the IS function. They both seem to do the same thing, but there must be a difference.
For the most part I am into airshows and motor racing, so the ability to pan both horizontally and sometimes vertically are the main requirements.
Can anyone help me out here