Camera/sensor safety taking photos of welding arcs?

Kit Lens Jockey

EOS 7D MK II
Nov 12, 2016
501
174
Does anyone know if it's considered safe for a camera sensor to take a photo of a welding arc with no special filter? I've seen multiple instances of lasers taking out sensors, and obviously prolonged photos of the sun is a non-no, but does anyone know with welding arcs?

I can say that I have actually done this before with a Rebel T3i. I was too inexperienced with photography to know any better, and I set up the camera on a tripod with it zoomed right in on where I would be welding, and triggered the camera remotely. The photos were really neat, and it doesn't seem like it damaged the camera or sensor, but did I just get lucky? I would love to do this again now that I'm more experienced and could probably take better photos, but is it safe for the camera? (Obviously I know that looking at a welding arc through a DSLR would be dangerous, but I would not be framing the shot at the same time that welding was actually taking place.)
 

Don Haines

Beware of cats with laser eyes!
Jun 4, 2012
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Canada
I have never shot active welding, but my first instinct would be to put a ND filter on the lens out of paranoia.
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
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Damage to the sensor would come from a long exposure, not a still photo with a fast shutter. However, the shutter itself could be damaged and possibly fail much earlier than normal.

Why not use a proper filter and not have to worry about eye damage if you inadvertantly look at the arc thru the lens.

A telephoto lens would likely be a bigger concern than wide angle.
 

koenkooi

EOS 7D MK II
Feb 25, 2015
437
261
For humans the danger from welding arcs is mostly the amount of UV light that gets emitted, so this might be one of the few cases where a UV filter can actually serve its intended purpose :)

Also, if you're close by and it's MIG or stick welding, pay attention to weld spatter, you don't want that on anything that you can't easily replace.
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
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For humans the danger from welding arcs is mostly the amount of UV light that gets emitted, so this might be one of the few cases where a UV filter can actually serve its intended purpose :)

Also, if you're close by and it's MIG or stick welding, pay attention to weld spatter, you don't want that on anything that you can't easily replace.
Canon sensors have a UV filter on them, thats why one is normally not needed .
 

Kit Lens Jockey

EOS 7D MK II
Nov 12, 2016
501
174
Why not use a proper filter and not have to worry about eye damage if you inadvertantly look at the arc thru the lens.
I'm not even sure what the "proper filter" for this would be. I've never heard of any filter designed for taking photos of welding. I assume maybe the closest thing would be a solar filter, but those cut down on the amount of light entering the camera massively, about 16 stops, so that's not desirable unless all I want is a photo of the arc itself surrounded in blackness.

I'm the person also doing the welding, so the possibility of inadvertently looking at the arc through the lens is not an issue. The photo would be framed beforehand and then triggered remotely or on a timer.
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
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I'm not even sure what the "proper filter" for this would be. I've never heard of any filter designed for taking photos of welding. I assume maybe the closest thing would be a solar filter, but those cut down on the amount of light entering the camera massively, about 16 stops, so that's not desirable unless all I want is a photo of the arc itself surrounded in blackness.

I'm the person also doing the welding, so the possibility of inadvertently looking at the arc through the lens is not an issue. The photo would be framed beforehand and then triggered remotely or on a timer.
There will be no issue with the sensor due to the short exposure time. The issue is damaging the aperture in the lens, melting lubricants, etc, so use a throw away lens if you don't use a filter and the exposure to the arc is more than a couple of seconds. The camera shutter blades can also be damaged by exposure to the arc. That's why a filter is a good idea, they can be rigged up for under $10 and protect everything. Welding filters are generally not as strong as solar filters, and can be purchased from a welding supply company. They are basically filters for welding helmets.They filter out the super strong UV, which is what does a lot of the damage.

The downside is color correcting the image due to the tint.

You can tape the filter over a lens or glue/tape it to a cylinder that fits over the lens.




 

Kit Lens Jockey

EOS 7D MK II
Nov 12, 2016
501
174
I was trying to figure out how dark welding filters actually are in terms of stops. They measure them in shade numbers which I can't find any correlation to anything. However I ran across this thread.

https://photo.stackexchange.com/questions/38502/how-do-welders-glass-shades-translate-to-stops-when-used-as-an-nd-filter

A welding filter is still very dark... Looks like at least 10 stops. Really designed to protect your eyes rather than to photograph through. Again I'd rather have a reasonable amount of light coming into the camera rather than something extremely dark that lets very little light through even if it's guaranteed to protect the camera.

I will probably just use my Rebel and a cheap lens. If anything gets damaged, it's not the end of the world. I still don't really understand what you're getting at with regard to the shutter being damaged. When is the shutter even exposed to what's coming through the lens? Are you talking about the tiny amount of time between when the mirror flips up and the shutter opens, or between when the shutter closes and the mirror drops back down? That can't be more than a few hundredths (thousandths??) of a second. I'd be surprised if anything would get damaged in that time.

I'm also thinking about the possibility of just moving the camera away from the welding and using a telephoto lens to capture it. If I'm not mistaken, UV light and the potential for damage from it falls off just as quickly as visible light. So at a certain distance, there would not be enough UV light reaching the lens or camera to do significant damage, even if there's a telephoto lens zoomed in on it.
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
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You are right about the shutter. A telephoto lens concentrates the light, so its harder on the camera and lens. A ND filter does not stop the strong UV, but does add some protection. Yes. welding filters are very dark. Welding arcs are extremely bright and concentrated. You can get by with a weaker filter for a camera.

Odds are that it will be just fine, the lens aperture would be the most likely thing to see damage, I'd stick with a ~50mm lens and not a telephoto. Damage to a aperture would only happen after a long period of exposure.

Example of a Telephoto lens with sun damage due to no filter.

 

Kit Lens Jockey

EOS 7D MK II
Nov 12, 2016
501
174
Is that one of the photos from the lensrental article on equipment damaged by the solar eclipse? I'm guessing that lens was trained on the sun for quite a while in live view, and/or had a ton of successive photos taken in a burst. For the amount of time the lens actually stops down to take a photo, I can't believe any amount of light short of a nuclear explosion would be that damaging to aperture blades.

Anyway, I took a few shots earlier this evening. I just used my Rebel T3i and my cheap-o 75-300 lens in case anything did get damaged. The darker areas of the photo have a little noise, and I'm sure a 5D or EOS R would do much better, but the Rebel still does pretty well at ISO 100. Well enough to not want to put a $2000 camera on the line.

184010
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
15,421
674
Good Job. Yes, that image is from Rogers article. And, Yes, it was likely from a long exposure to the sun, a short exposure it unlikely to hurt, but you really can't tell if the lubricant was melted and broke down.