Have you considered the 24-70L?
If you are shooting outdoors with plenty of light, IS might not be an issue for you. Besides, IS won't help you stop subject movement.
The 24-70L will have better bokeh qualities than the 24-105L. It really depends on how busy the background is. When it is indeed busy, the 24-105L's bokeh can be "distracting" at times. It doesn't have the smooth/creamy bokeh.
Otherwise it's a fine lens. Really, you could also say since you ARE shooting outdoors most of the time, the f4 might be good enough. But I would really think about the bokeh on the 24-105...PLENTY of threads on that!
showtm490 wrote in post #4583149
Mostly I'll be shooting models and 80% of the time its outdoor shoots. I love my Tamron but I keep thinking I'll get more use out of the 24-105. Sadly the Tamron will need to go to cover the cost of the Canon.
Also I'm shooting with a Rebel XT.