He was observing the distant birds with binoculars.

He was observing a three-dimensional image using a stereoscope.

In physics class, I learned about the properties of convex mirrors.

This magic mirror came from China.

He attached a new reflector to his bicycle.

The speculum of this bird has a very beautiful color.

He was observing the stars with a telescope.

The bird called Ruanjing that appears in Chinese mythology is known for its beautiful appearance.

He conducted an experiment using a spherical lens.

This Tang mirror is a gift from China.