Brendan,


While I can not give you any information on the 24-105, I have to defend the 17-55. I have a 50D and my 17-55 is still my most used lens. I also have the 24-70 and when I really need a keeper from only a few shots, I take the 17-55. Granted most of what I do is indoors, I have had zero issues with dust and would dismiss that complaint as an issue. My reason for the 24-70 over the 24-105 was the 2.8 because it is a must for me. Today I took over 200 pictures in church, mostly of our children's choir and all but one were sharp. The one that was not was in a burst where I misjudged movement of the children as they did a dance, but shooting at high speed that is easily done sometimes.


If you shoot in inclement weather or dusty conditions, then sealing is an issue. Since my camera is not sealed on par with the L lenses, that is not a factor for me. If that is not in play for you, then it comes down to what you are doing. If you need to stop action in less that perfect light, as I often do, then you want the largest aperture. If you are shooting still or slow moving subjects in good light then go for the zoom range. With the right lens for the situation I think you would be pleased with results from any of the three. They are the top three recommendations of Bryan.


Good luck choosing. I have been there myself, even when I started asking opinions, I was leaning towards 24-70 and in the end that is what I purchased. For what I do, it has been the right choice. Now, I am debating an upgrade between a 7D and the new 1D Mark IV. Any opinions from your experience with your 7D would be greatly appreciated.


Chris