My husband and I are planning on buying a Canon T2i and I was wondering what the difference is between the 18-135mm lens and the 55-250mm lens. I have two kids and I'm tired of taking blurry pictures because they don't hold still long enough to take the picture. I want a camera that has a fast shutter speed that can take a good bright picture inside and out without being blurry every time someone moves. We also don't want to spend a ton, no more than $700 probably. Curious what your recommendations are.