Go for the 17-55 or 15-85. If you need f/2,8 very often, go for the first one. The second may be slightly sharper on the equivalent apertures and is certainly more versatile.
I held of buying the 24-70 for a long time because of its size/weight and reviews but after trying many other lens in this range ( 28-135, 17-40, 35 1.4, 50 1.4 ) i finally picked up a 24-70 about 18 months ago and love it. Having 2.8 across the range is excellent. Everyone is different but for me this lens just covers a perfect range on a crop body. Its not a small lens but then carrying around a mix of zooms and primes is no fun either. I don't really notice the size or the weight now but i much prefer not having to change lens all the time. If your going to end up with the 24-70 i would go for it now and save yourself money. I've since sold all other lens in this range.
If your eyes are on FF anyways, get the new Tamron 24-70 VC and an APS-C UWA like a Tokina 12-24, that'll have you well covered. YMMV but I never thought 24mm equivalent, let alone the 28mm equivalent of the 17-55 - is always wide enough so you'll be probably wanting something wider a lot of the time. Once you get around to upgrading, you'll sell both the UWA and the camera, and be left with more cash to fund the new body.
17-50 is a great lens, IS and 2.8 are great for low light--more useful than faster primes for my purposes. I shoot at 17 a lot so 24-XX options wouldn't work.
BiggHarry wrote:
My suggestion would be 17-55 unless you are planning to switch to the FF very soon.
I use my 17-55 on my 7D a lot and it is great lens. While 15-85 is more versatile outdoor, indoor 17-55 is a king.
same here, or if budget is a concern the Sigma 17-50 or Tamron 17-50 2.8
