制作你自己的相机

A pinhole camera from a paper bag

Walking in the pinhole world

An orthographic camera from straws

The tradeoff that motivates the lens

A camera made from a bundle of long, thin, black-lined straws produces an upright image in which objects at different distances appear at the same size. Which explanation of the straw camera's geometry is correct?

A paper-bag pinhole camera shows a dim but reasonably sharp image. The maker enlarges the hole to four times the area. What happens to the image, and why?

A straw-bundle camera projects orthographically at unit scale, $k = 1$, so image size equals world size. An object of height $Y = 3$ stands anywhere in front of the bundle. Write the height of its image on the screen.