I just got the Rebel Ti and I presume im going to need a better lense then the one it came stock with. I will be traveling to italy and as you all know italy is filled with great country side, amazing art, buildings, and great statues and much more. What I need some help with is how to decide waht lense to get? and any Ideas? Could someone also explaing like when i see 28-9mm/1.8D Im not understanding the 1.8d part thats all. Just throw out some ideas thank you