I'd like to replace my 18-70mm (kit lens) with a fast lens (2.8). I don't like to use flash, so that's the main reason. Don't care too much about the wide-angle (I don't photograph too much of lansdscape). I saw that most of the standard zooms start at 24mm. That's ok. I'd rather have a more zoom in the end. I often hear that you should buy the same brand as your camera (faster focus). Is it true? Any suggestions? I am waiting for my yearly bonus to come in, wo why not buy something new for my camera?