I bought one on Amazon for $30 (brand is AUKEY) and used it with my iPhone on a recent hiking trip. You have to be careful of aligning it perfectly, but it's a

I bought one on Amazon for $30 (brand is AUKEY) and used it with my iPhone on a recent hiking trip. You have to be careful of aligning it perfectly, but it's a huge help when photographing landscapes with a phone. You can capture a noticeable amount more of the scene.