Underwater Photography Glossary

A diopter is a magnifying element that screws on to the front of your lens. They come in multiple sizes and strengths. For macro photography, diopters can decrease the focal lengnth for super macro images. For wide angle zoom lenses, often diopters help to compensate for minimal diffraction to create sharper images. High quality diopters are the ones with two lens elements - single element diopters should be avoided.