Eyes

Pinhole eye

The pinhole eye is an "advanced" form of pit eye incorporating several improvements, most notably a small aperture and deep pit. It is only found in the nautiloids Without a lens to focus the image, it produces a blurry image, and will blur out a point to the size of the aperture. Consequently, nautiloids can't discriminate between objects with an angular separation of less than 11°. Shrinking the aperture would produce a sharper image, but let in less light.