Boasting the superb build, mechanical and optical quality found in the Canon L-Series Lensesand a widely used range of focal lengths, the Canon EF 24-105mm f/4 L IS USM Lens is one of the best and most popular Canon general purpose lenses made. The Canon EF 24-105mm f/4 L IS USM Lens quickly became one of my favorite and most-used lenses. If I had only one lens, this would be the one. 
 
One of the most important features in a lens is the focal length or focal length range - get it wrong and you might not be able to take the shots you want. And the use for a particular focal length or focal length range varies, of course, depending on the FOVCF of the body being used. That said, this lens gives us a very nice general purpose focal range to work with. On a full frame body, 24mm is very wide. On a 1.6x body, 24mm is only moderately wide (equivalent of 38.4mm). And the advantage or disadvantage - whichever it is for you personally - is the opposite on the other end as well.