Are there any lenses that any of you use for low-light photography that aren't L glass? Don't get me wrong, I love L lenses, but they're a little over my budget right now. I've been eyeing the 24-70 for a while, but right now I can't afford it - plus i'd still like something wider.
I've looked up the Tamron 17-50 2.8 and was sold until I saw someone said it doesn't focus well in low light. I currently have the Sigma 17-70 IS and that also doesn't do well in low light, so i'm looking to sell it and get something better.
Any suggestions? I tend to mostly just shoot for fun, but I do do some concert photography here and there and a lot of night photography, so i would like to build up some lenses that will work well for that since that's where a lot of my interest is.
Thanks! 



