Okay, instead of comparing lens models, how about this: I'm going to photograph some live butterflies at an indoor botanical garden at the Indianapolis Zoo later this month. I have a Canon 40D. I want to capture clarity and color. Which lens should I use? The 24-105 mm? The 24-70? I know from experience I'll need to do a little zooming in, so the 100 macro is out. What are your thoughts?