A school outing

A：What are you doing? Bob?
B：I'm looking for my lunchbox. Where is it?
A：Is this one your lunchbox?
B：No, it isn't. It’s John's lunchbox. My lunchbox is blue, but his lunchbox is green. 
A：What's that under the map?
B：Yes! It's my lunchbox. Thank you, Mary.
A：That's all right. By the way, where is our camera? I want to take some photos, it's so beautiful here.
B：Look there! Our camera is in John's hand.
A：Let's go there and take some photos!
B：Good idea!