I would get a #10 (or more depending whats being welded) 4"x5" welders filter glass and put it in front of the lens. It's dead cheap, you can buy that for under $10 at any welders supply shops like BOC gases.
I have no idea if the cameras sensor will be damaged without a filter, but I would not take the chance.
As a bonus, you'll be able to use it to photograph/stare at the next solar eclipse
(actually NASA recommends a #14 filter for eclipse watching, but I've used a #10 in the past)
Pat
EDIT: It is not EVER safe to look at an arc welding operation without eye protection, the arc is bright enough to blind you, and tiny droplets of metal splatters! Protect your eyes (and lens!)