The camera lens has three functions:like a fish eye, it is thicker in the middle, surrounded is thiner; 

 

it can widen horizons; and it has a macro,so it can see things clear far away.When you want to take a more clear photo, see more clear in distance, or you want to take for more scene.

 

The ordinary lens can't do it,but this one can. 

 

And it is not too big,very easy to carry. it is popular and fashion now.