what do you want to photograph  thin beast? Different kind of photography needs different kind of lens. Share what you want to take pictures of mostly, then people will be ab;e to answer you mroe precisely. 

just looking at your post, I see you have a 18-55mm lens. If you just want to own another lens, I suggest any 55-200(300) mm will complement your current lens. This is just my general suggestion. Thanks. 


Sparrow