\(power \ of \ a \ lens \ (D) = \frac{1}{focal \ length \ (m)}\) A lens has a power of -3.33 dioptres. Calculate the focal length and state what type of lens it is.

But you can also see some distortion on the left of the image due to the lens being poorly placed; I include this to show how easy it is to accidentally mess up a shot on the lens (and I excuse ...