A welding arc is extremely bright, but because it’s brief and localized it’s generally less of a camera risk than something like prolonged sun exposure. Damage is unlikely in normal use, though caution is sensible: avoid pointing the camera at the arc longer than necessary, and keep some distance from heat and sparks. A clear protective filter can help protect the front element from debris; an ND filter may reduce light, but many photographers shoot welding without one.

The main challenge is exposure. The arc will usually blow out, so expose for the surrounding scene and accept the weld point as a bright highlight. Auto exposure may underexpose everything else, so manual settings are often easier. If you want more detail in the environment, add fill flash or shoot in strong ambient light. You can also partially hide the arc behind the workpiece so the glow remains visible without dominating the frame.

For sparks and arc trails, try longer shutter speeds; for a more natural-looking process shot, use shorter exposures. Experiment with aperture: a range of apertures can work, and letting sparks move from in-focus to out-of-focus can look good.