[citation needed] In his late twenties, Feinstein was hired as a production intern at Columbia Pictures, later a studio photographer.

[7][6][5] He subsequently became a photographer in Hollywood, where he worked with Marlene Dietrich, Judy Garland, Charlton Heston, Jayne Mansfield, and Steve McQueen.

[citation needed] His photos of celebrities, as well such politicians as John F. Kennedy and Richard Nixon, appeared in national publications, including Time, Esquire, and Newsweek.

[citation needed] In 1966, Feinstein accompanied Bob Dylan on his tour of England,[8] and shot the cover photos of numerous albums by Janis Joplin, George Harrison, the Rolling Stones, and others.

[5] During Mardi Gras in late February 1968, Feinstein, Les Blank, Baird Bryant and others were in New Orleans as part of the original "underground filmmakers"[9] crew of Easy Rider that produced the acid trip segment of the movie on 16 mm film, but was replaced afterwards by a more experienced crew with 35 mm movie film.