Hi again,


Here is why I would not bother to drop the $1000 on the 17-55mm if I were going to buy a FF (in the relatively near future) and keep my ASP-C: first, the focal length of the 24-70mm is just fine for me. I currently own the EF 24-85mm f/3.5-4.5 USM and seldom do I find myself wishing that I had a wider angle lens (I am running it on a 10D). Second, my backup camera would seldom cover the same ZOOM range as the FF and would most likely have a fast prime on it, especially if I were shooting a wedding indoors where light is often low. Third, I would want to have my best glass on my best camera. Fourth, (it has been said don't worry about this now as you don't have wx on the 40D but,) weather sealing will eventually be a great thing to have as there are certain shots that you just can't get unless you are in a dusty or wet place. Combine the 24-70mm and the 5D Mk II and you will have a great outdoors weather sealed setup. Finally, it would be just fine with me (if it were feasable) to get the 24-70mm and complement it with the 10-22 on my ASP-C camera. Then you are covering the whole gamut on you ASP-C and later with the FF body you will be able to have a wide lens on your backup and a nice walk-around lens on the FF.


If you are not so keen on having the 24-70mm right away I would again recommend you check out the Tamron 17-50mm review on this site. It may be a good lens to tide you over till you get that 5D Mk II (or whatever you might buy).


Also, Sean, you said, "there isn't a lens comprable to the 17-55mm (at this time) for FF bodies" and I would not thoroughly agree; the 17-55mm covers and equivelent 27-88mm range which is very close to both the 24-70mm f/2.8 and the 24-105mm f/4 IS. Granted I understand that you either have to have a slower lens with IS or the faster one without it, but to me IS is not necessarily the answer. Each person will have to decide on that because one lens can shoot in less light as long as the subject is not moving while the other can shoot at faster. Many of my shots are of moving subjects anyway, (especially when light gets low) so it would not really benefit me too much to have IS. Just a thought.


Hope this makes sense and helps a little,


Samuel