Just when the fashion magazines have gone back to using a lot of drawings, along comes an announcement of shows by photographers who have had a major impact on fashion photography.

The first major retrospective in more than 20 years of Irving Penn's work will open at the Museum of Modern Art in New York on Sept. 13. His remarkable portraits, fashion editorials, advertising work, nudes and still-life photography, as well as some of Penn's early unpublished works, will be included. (The Penn show will be at the Corcoran Gallery in 1986.)

The International Center for Photography in New York will exhibit the works of Horst P. Horst, a German-born photographer, and an American citizen since he served in the U.S. Army in World War II. Horst started working in Paris in the 1930s for Conde Nast and is best known for his work in Vogue and House & Garden. Among the well-known portraits to be included in the show are those of Coco Chanel, Luchino Visconti, Janet Flanner and Marlene Dietrich. Like the Penn exhibit, the Horst show will feature some unpublished works, including some of Horst's nudes and nature studies.

Additionally, an exhibition of photographs by Richard Avedon, called "In the American West," will open in Fort Worth in a year and come to the Corcoran in December 1985. Avedon's fashion photographs, which have dominated fashion magazines for more than 35 years, have been the subject of a retrospective at the Metropolitan Museum of Art.