documentarian

[ dok-yuh-men-tair-ee-uh n, -muh n- ]
/ ˌdɒk yə mɛnˈtɛər i ən, -mən- /

noun

Movies, Television. a filmmaker, producer, etc., who specializes in documentaries.
a writer, photographer, or other artist whose work constitutes a document or documentary of an aspect of life.
Also doc·u·men·ta·rist [dok-yuh-men-ter-ist] /ˌdɒk yəˈmɛn tər ɪst/.

Origin of documentarian

First recorded in 1940–45; document(ary) + -arian

British Dictionary definitions for documentarist

documentarian
/ (ˌdɒkjʊmənˈtɛərɪən) /

noun

mainly US a person who makes documentary films