noun
conversion lens; converter lens
Photography term for a lens attachment that changes the focal length or other optical properties of the primary lens.
このコンバージョンレンズを使うと、広角レンズが望遠レンズに変わる。
Using this conversion lens turns a wide-angle lens into a telephoto lens.
Variant with interpunct; less common but still seen in some contexts.
Borrowed from English 'conversion lens'.