Koushirou is my best friend.

Kou Sennen is my best friend.

Photochemistry is a branch of science that studies how chemical reactions proceed under the influence of light.

The photoelectric effect is a phenomenon where a material emits electrons after absorbing light.

He has a collection of stamps.

There were many people gathering, and the park was bustling.

My new camera comes with a zoom lens.

A Fresnel lens is very effective at gathering light.

This lighthouse is using a Fresnel lens.

I'm looking forward to taking landscape photos with my new wide-angle lens.