From this story on CBC News:
A B.C. filmmaker says he’s lucky to be alive after narrowly avoiding a grizzly attack while filming in the Robson Valley, southeast of Prince George. Leon Lorenz, who lives in Dunster, B.C., was filming grizzly bears in a nearby valley last Monday evening when he spotted a bear and her cub. Lorenz said he was attempting to film the bears without disturbing them, but the mother bear picked up his scent.

_She turned suddenly, he said, and looked him right in the eyes. Then, roaring, she charged through the trees right at Lorenz. He recalls thinking, “This is for real. This is ∑ no bluff charge.” Lorenz set the camera down on a tripod, capturing everything on film, and grabbed his handgun with the hopes of firing a warning shot to scare the grizzly off.

Crouched behind the tree, he aimed his gun high and pulled the trigger ˜ just as the grizzly burst through the branches of the tree, a few feet from where he was hiding. Lorenz said the shot spooked the bear, which he estimates weighed between 400 and 500 pounds, and she ran off with her cub. “I knew if I would have run, I wouldn’t be here,” he said. “If I didn’t have my handgun, even if I would have fired a shot a quarter of a second later, the blast would have been too late. She would have been on me.”_

Watch the video. Just make sure you watch it from somewhere you can change your pants afterward…