Here's an interesting one, well to me anyway.

For various reasons I may have a need to film the act of TIG welding (a form of arc welding). Now the intensity of light given off by this is phenomenal, and I'm wondering if I need to go serious ND filters, or will it be OK? Not only for the image point of view, but for the safety of the camera.

My heart says I need filters, lots of them

I would only considor this filming through welders galss or a myler sun filter.

An arc makes the sun look like a candle.

And mind your self too - I burned all the skin on my forearms from welding once - UV burns.

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In the same way that you should never point an unfiltered camcorder at the sun you should be just as careful with point sources like arc welding. Your lens is gonna focus that light onto a minute point on the sensor which could (if you're unlucky) kill a few pixels or, at worse, ruin the whole chip.

Yes that was my fear, I've got some glasses from a welding hood somewhere, I guess I'll pre-focus on the weld zone and then apply the filter before the guy strikes an arc.

Filmed arc welding a few times using appropriate ND filter. Either use auto iris which is quicker than your hand when the arc strikes, or alternatively, close your iris and set on a test weld. Film from a safe distance to avoid spatter on your cam and lens, but zooming in to get the 'flashy' close ups.

I was planning on using my cameras macro zoom facility, to keep a safe distance etc, I'll also be peering thorugh a welding screen for my own safety.

I wish I could adjust the iris, not that sophisticated yet! LOL!

I think I'll see if a light meter tells me anything, I've no idea how light readings transfer over on to video, but it might give me a pointer, either way I'll start with lots of filter protection and remove it as necessary to get a result, I might even use one of my older cameras just in case. It's only for few seconds of footage, so it's no biggy if it doesn't work out, it would just be nice if it did.

Thanks for the advice guys, I've enough to be getting on with now .

make sure your shield is at least a #10 or #12. TIG is a different process then ARC or MIG and the light intensity is much higher. Using a #8 which is standard for MIG will still make your footage (where the arc is) to bright to see the wire and tungstan working.

Yep, thanks for that, I would have used what the workshop has, which would be the ones you mention I guess.