RED and welding flash

[Ryan Damm]

Hey all,


Any thoughts on shooting welding (and protecting the chip)? I'm thinking about shooting through standard welding glass (cut to fit in a filter holder), but I'd love to hear from someone who's done it before -- either on RED or another video camera (I suppose film experience would be interesting, too).

Thoughts?


-Ryan

[Jeff Kilgroe]

Weld glass will definitely work... But may leave the surroundings a bit too dark, depending on what you're trying to shoot.

Strong ND is the way to go, doesn't have to be as dark as most welding glass, which is also available in different types and densities, BTW. Most welding glass these days is actually polycarbonate or will have polycarbonate layers over glass. Polycarbonate blocks UV rays very efficeintly.

Do you know what type of welding you will be shooting and what materials? Tig, mig, heliarc, etc.. produce various levels of UV and you may be able to get away with lower ND levels on some. How close will you be to the arc? You may need an IR cut filter for this too, also depending on what welding process.

...I haven't shot any welding with the RED One yet. Did shoot some with the HVX200 and I took apart a LCD welding helmet. They type where the helmet will detect the initial flash and darken the LCD. I mounted the glass / sensor element over the camera lens, so I could go from shooting surroundings and then directly to the weld arc.

FWIW, I don't recommend such welding visors to anyone for regular use -- after you use them a bunch, you'll quickly see that the weld flash is indeed faster than the LCD system and you get nailed with full weld arc for about 1/2500th of a second or so every time. Hard on the eyes if you do it every day. But worked great for the camera -- I guess I didn't care about taking the vizor apart because I hated it anyway. Besides, there's much better solutions to protect eyes there these days.

[Mike Harrington]

those helmets are ok for regular use...
i worked in shops for like 10 years, and the response time is 1/25000-1/30000 of a second for most moden helmets...10 times the speed of the factest lcd moniters...probably have a bigger risk of injury from neck strain with the old style helmets then you do eye injury with the new ones

http://www.diytrade.com/china/4/products/4498922/Auto-darkening_Welding_Helmet_Sensitivity_Delay_Time_Ad justment.html

walk downtown bankok....or some of these other countries, i saw guys weld by squinting, and wearing sunglasses....all while barefoot and sqauting....seriously like 5 guys.....one guy had glass from a welding helmet stuck on the end of a stick, but he was the only one.......the welds were a little ugly too

that was 5 years ago...there probably blind by now

[Michael Brennan]

My experience has been thta CCD cameras don't have a problem I would expect CMOS to be the same.

But a prolonged locked off shot of a robot welder isnt prudent.
Try different shutter speeds to explore how the sparks are captured. A ND will be handy as well


Mike Brennan

[Jeff Kilgroe]

those helmets are ok for regular use...
i worked in shops for like 10 years, and the response time is 1/25000-1/30000 of a second for most moden helmets...10 times the speed of the factest lcd moniters...probably have a bigger risk of injury from neck strain with the old style helmets then you do eye injury with the new ones

Yeah, the guys at the welding supply stores and sales reps from most companies tell me the same thing about their vizors. But after I spend 8-10 hours a day in one for a couple weeks straight, I still end up with red and irritated eyes and visible UV burn (sun burn, but from a weld arc). So I've done away with those vizors. I guess they're OK, depending on usage, but when I'm exposed to a couple hundred arc flashes in a day, those 1/25000-1/30000th of a second must add up. I've gone to the vizors that sync with the welder rather than off a flash-sensor. That way, there's a 1/1500th of a second delay going the other direction, vizor dark, then arc.

BTW, I have my own welding fab shop and started welding when I was 11 or 12 years old. My background is all heavy construction / demolition. I do this filmmaking stuff as a hobby and have only recently started trying to make money with it. Not sure if I like actually doing it as a business... Much easier to make money by tearing down bridges and moving mountains.

I might try shooting some welding stuff with RED this next week if I have time. It's on my to-do list.


walk downtown bankok....or some of these other countries, i saw guys weld by squinting, and wearing sunglasses....all while barefoot and sqauting....seriously like 5 guys

hehe... Sounds like one of the old guys that used to work for my grandfather. He would be standing on his head under a piece of heavy equipment, welding a plate on something or whatnot. usually wearing nothing more than shorts, flip-flops and a pair of cheap sunglasses he bought at the gas station. I used to ask him to put some clothes on, to which he would respond, "what? and ruin a perfectly good shirt?"

My personal favorite is cuttong on something overhead and you get a glob of molten steel down your neck. The ones that go all the way down your shirt and into the crack of your ass. Wooohoo! ...I don't weld in shorts and flip-flops, but I'm no fan of all the protective hoods and other gear that some guys wear. Can't move or breath in that stuff. I usually just wear a welding cap, vizor, shoulder leathers and good gloves. And that's for the big stuff I'm welding or cutting. For small jobs, just the gloves and a vizor will do, especially if I have the luxury of working on a table and not underneath some large piece of equipment or hanging from a bridge girder.

[Mike Harrington]

My personal favorite is cuttong on something overhead and you get a glob of molten steel down your neck. The ones that go all the way down your shirt and into the crack of your ass. Wooohoo! ...

sound like fun

the worst i ever got was in the ear, you can hear it crackle over your own screams!!
up the nose is annoying as well

one time i cut a bolt off with a torch, the glowing red chunk fell into my jeans pocket and melted it's way through the crotch of my jeans.....never touched the jewels thank God

i was an ironworker for like 15 years...getting out after they force us to tie off and ride a manlift instead of climbing
safety nazis

[Ryan Damm]

Wow, good war stories, guys. And great advice.

Here's what I'm doing -- I'm shooting some welding videos for the startup I work at -- TechShop... we're going to video MIG, TIG, oxy-acetylene, and plasma cutting, so I'll probably be using a range of welding glass.

I'm really looking for two kinds of shots -- the pretty ones (probably using a little less welding glass than I would for my eyes, to retain some detail outside the weld pool), and the functional ones (showing exactly what you'd see if you were welding).

I'm glad to hear that there probably isn't a huge danger to the sensor -- I'll be stacking a UV filter inline, and though I'm not super-concerned about IR, I'll shoot some careful tests first.

Thanks, all!

[Brian F Kobylarz]

I've shot a lot of welding and cutting: carbon arc, lasers, plasmas, TIG, MIG, electron beam, GMAW, etc. in my career. Everything from a series of tapes on welding inspection for AWS to filming the construction of nuclear subs and many other industrial applications.

My advice:

Before anything else - start with expendable glass at the front of the filter line-up. There is nothing worse than finding small droplets of metal that have fused into the coatings of a good filter or expensive lens. You might as well throw the glass back into a desert.
The molten metal that can damage your equipment is not only the weld spatter you see as the sparks, it is also in a small cloud around the weld bead. I watched on a monitor as the lens on a lipstick camera slowly fogged over while capturing some laser welding - no spatter - just hot metal particles floating in the air.

Make use of ND versus welding glass. Plenty of it. Filming a normal arc requires a smaller aperture than a broadcast or film camera lens can achieve. Start with a .9 at a minimum. I usually stacked two of them.
If you use the shutter, the visual effect of the "sparks" will change. Some people like the trails - but technically, you don't want them during welding - that weld spatter can cause quality issues.
Rather than chase the f-stop, preset the exposure and focus where the weld is going to start. Then let the welder start - while some glass is designed to react, nothing reacts as fast as that burst of light when the arc is struck.

The amount of light that a welding arc produces is intense. Sometimes you just want to see the welding bead - if you expose just right, you can get some interesting visuals - I remember capturing some keyhole welding shots where the molten metal formed a small whirlpool just behind the arc before it filled back in - another shot where silica was dancing on top of the pool - but I digress.

If you want to see the area surrounding the weld bead, you need to begin thinking of it in terms of a dynamic range issue. How many stops difference between the arc (which is a light source) and the adjacent metal? Since the arc is a light source, there is plenty of illumination right next to it, but it falls off fast. That's great for the close ups, but if you need to see more, you will need to hit it with a lot of lighting - Spotting a couple of 1.2K HMI PARS is a good start.

For the medium shots showing the welder in action, let their glove or body block the arc and expose normally.

Really important:
Protect your own eyes. Do not watch the welding process without proper protective gear. Welding flash is real. It doesn't hit you right away - but a few hours later you will feel as though someone scratched your cornea with sandpaper. Over twenty years later I still remember that lesson.
Do not use the LCD as your monitor - it does not give you the protection. However, you can watch the welding arc through the viewfinder. With RED or other video cameras, it is not an optical path - so you are in effect - watching it on TV. Not so with many film cameras (and some video such as the ARRI D20) - if there is an optical path, you need to protect your eyes.

[Brian F Kobylarz]

Note: I posted this on 08/23 - it showed up in one area, but not in the thread - trying again... If this shows as a duplicate, my apologies

---------------------------

I've shot a lot of welding and cutting: carbon arc, lasers, plasmas, TIG, MIG, electron beam, GMAW, etc. in my career. Everything from a series of tapes on welding inspection for AWS to filming the construction of nuclear subs and many other industrial applications.

My advice:

Before anything else - start with expendable glass at the front of the filter line-up. There is nothing worse than finding small droplets of metal that have fused into the coatings of a good filter or expensive lens. You might as well throw the glass back into a desert.
The molten metal that can damage your equipment is not only the weld spatter you see as the sparks, it is also in a small cloud around the weld bead. I watched on a monitor as the lens on a lipstick camera slowly fogged over while capturing some laser welding - no spatter - just hot metal particles floating in the air.

Make use of ND versus welding glass. Plenty of it. Filming a normal arc requires a smaller aperture than a broadcast or film camera lens can achieve. Start with a .9 at a minimum. I usually stacked two of them.
If you use the shutter, the visual effect of the "sparks" will change. Some people like the trails - but technically, you don't want them during welding - that weld spatter can cause quality issues.
Rather than chase the f-stop, preset the exposure and focus where the weld is going to start. Then let the welder start - while some glass is designed to react, nothing reacts as fast as that burst of light when the arc is struck.

The amount of light that a welding arc produces is intense. Sometimes you just want to see the welding bead - if you expose just right, you can get some interesting visuals - I remember capturing some keyhole welding shots where the molten metal formed a small whirlpool just behind the arc before it filled back in - another shot where silica was dancing on top of the pool - but I digress.

If you want to see the area surrounding the weld bead, you need to begin thinking of it in terms of a dynamic range issue. How many stops difference between the arc (which is a light source) and the adjacent metal? Since the arc is a light source, there is plenty of illumination right next to it, but it falls off fast. That's great for the close ups, but if you need to see more, you will need to hit it with a lot of lighting - Spotting a couple of 1.2K HMI PARS is a good start.

For the medium shots showing the welder in action, let their glove or body block the arc and expose normally.

Really important:
Protect your own eyes. Do not watch the welding process without proper protective gear. Welding flash is real. It doesn't hit you right away - but a few hours later you will feel as though someone scratched your cornea with sandpaper. Over twenty years later I still remember that lesson.
Do not use the LCD as your monitor - it does not give you the protection. However, you can watch the welding arc through the viewfinder. With RED or other video cameras, it is not an optical path - so you are in effect - watching it on TV. Not so with many film cameras (and some video such as the ARRI D20) - if there is an optical path, you need to protect your eyes.