Nick Oliveri and Hank von Hell… and captions!

Captions. What is a good caption? How long should it be? Does it have to explain everything? Very often I don’t write much, maybe just the person, place and date.

Nick Oliveri and Hank von Hell

Nick Oliveri, known from Queens of the Stone Age, does a guest appearance with Turbonegro, the Norwegian death punk band playing their album Apocalypse Dudes from start to end at Øya Festival 2008, Oslo, Norway 2008-08-07. Oliveri sang "Back to Dungaree High" and "Nervous Breakdown," the latter a Black Flag cover. Copyright Espen Stranger Seland / seland.org

Any good tips to what makes a good photojournalistic caption?

Maybe this example with Nick Oliveri and Hertis is a tad too much, but maybe not. Feel free to leave some comments or links.