First of all, my gear:
Body: 5d mkiii
All purpose zoom: 24-105mm f/4L IS USM
Tele-zoom: 70-200mm f/2.8L IS mkii
Primes: 8mm Rokinon fisheye & 100mm f/2.8L IS Macro which I am selling and will replace with a 135mm f/2L which will then eventually be replace by an 85mm f/1.2L prime
Speedlite: 430ex mkii and I am in the market for a 90 ex to use as a hotshoe master for off camera triggering.
Now the circumstances I find myself in. I was looking for a backup for my mkiii just incase it decides to flip out one day and I'm stuck without a camera for a week or two (though I know CPS is good about giving you a temporary replacement.
Well... what I did was buy a 17-55mm and a 50D. I previously had a 60D and my lone issue with the 60D was the lack of AFMA. I know AFMA is less of a concern at f/4 and above, but as discussed above, I'm looking at f/2 and eventually f/1.2. And yes, I will more often than not use those lenses on the mkiii, but you never know.
Part of the reason I wanted the 17-55 is to get a sense of the focal length. On the 50D, the focal length is roughly 27-88. If I have the focal length, then I know I won't care for the 24-70 f/2.8L USM mkii. Also, the extra stop would be nice... but again... if I'm going to an indoor event... I can't imagine taking the 50D over the mkiii.
So am I going to use the lens? I'm almost leaning towards no. I have it up on Amazon, so if it sells the decision is out of my hands... Dang EF-s...