What was it like to travel with Led Zeppelin?

And what really doomed Jim Morrison to an early death?

Rock photographer Robert Knight plans to reveal all during a rare appearance from 6 to 9 p.m. Friday.

“Jim Morrison was self-destructive” Knight said, “the drugs were whacking him out. He scared me. I shied away from shooting him.”

But Knight didn’t hesitate to photograph other rock legends including the Rolling Stones, Eric Clapton, Stevie Ray Vaughan and Elton John, during a career that spanned 40 years, beginning in the ‘60s.

More than 40 famous photos from his collection will be part of a free showing. Included are the last photos taken of Vaughan, just hours before his tragic death in a helicopter crash.

“The next day, Rolling Stone magazine and everyone called me (for the photos), and I wouldn’t let them out,” he said.

“I couldn’t do it. They were my friends.”

Knight attributed much of his success as a photographer to his access to the stars, many of whom he befriended.

“Actually, Elton John let me come right up to the piano. The point of view I had was better than any other photographer.”

Staying off drugs also was a plus for Knight.

“I never so much as smoked a join,” he said, explaining that his interest in psychic research made “the idea of staying pure” appealing to him.

All of which contributed to his uncanny ability to capture rock icons during what were often chaotic, riotous concerts.

“Knight’s photos are in credible,” said Michael Dunn Gallery owner.

“and when you realize the stories behind the photos – what was going on backstage, on stage, during a tour or intimate photos off tour – then we have a wonderful appreciation and understanding of what was just a photograph.