Focal length – The shorter, the wider
Focal length manifests a camera lens’ ability to converge the light, or in a simpler way, how hard it bends the light. If it’s better at converging the light, the beams from different angles will meat each other faster, leading to a shorter focal length. Besides, the stronger ability enables it to squeeze more content into the image frame, so you will get a wider angle. On the contrary, a longer focal length will result in a narrower view and a close-up of details.