So long story short...my temporary/seasonal position turned into a permanent job. For this job we have a 5dii, which I will be the only one that ever uses it and only use it on 5 or so occasions a year. Which means I have access to this camera year round and as long as I dont break it, can use it whenever I want.

Which is great because its a heck of a step up from my 50d. But that's where my question starts.

The dilemma is this,

My personal gear is
50d
17-55mm 2.8
100-400mm

work gear is:
5dii
28-135(You can probably see where the issue is already.)

I think it makes sense to keep using the 50d for all my wildlife photography if not only because of the 6fps. Although it seems silly to use the 50d for landscapes and people(which I'm shooting more and more of) when I have access to a 5dii. Problem is that the only lens we have for the 5d is the 28-135mm (which leaves something to be desired) and obviously my efs 17-55 won't work. So since I will be in this position for the foreseeable future, should I sell the 17-55 and get something that will work on the 5d? I think so, but what? I love my 17-55.... f2.8 is awesome to have and I also use the IS a lot since I often use this lens in low light . Obvious choice is the 24-70mm but I wonder if I will miss the IS. I also sometimes wish I didn't have such a big gap between my lenses from 55mm-100mm, and the 70mm on the full frame will feel like an even bigger gap. so maybe I should consider the 24-105? but then I loose a stop of light.


What else should I be considering? (I've thought about primes but it would take a lot of convincing to get me to actually make the switch) The budget is also limited to what I can sell my 17-55 for, give or take a little.