I am new to photography and am helping out at work taking photos of manufacturing steel, primarily welding.
I was wondering if anyone could help me in what are the bests camera setting for this kind of work.
The workshop is reasonably lit but most photos i take he worker is in good focus and colour but the weld is really bright.
I am using a canon 700D with an 18-135mm lens.
any advice will help.
There is nothing particularly special about photographing welding... it is very much like photographing fireworks.
The main thing is to stay back and use longer focal lengths to get the composition. Use smaller apertures like f/11 for adequate depth of field, and slower shutter speeds of around 1/125 to get spark trails. Use a tripod and remote release (not looking through the viewfinder) and shoot in small bursts. I would also be using full manual settings for this.
If you photograph the welder from the arc side the brightness of the arc will also illuminate the welder to nearly the same brightness and equalize your exposure. If you photograph the welder from the dark side the ambient and the arc will be very dissimilar; and you would need to add additional lighting on the welder (using flash)... this will actually help freeze/focus the welder in combination with the long SS for the spark trails, but complicates the setup and the work environment (you might need to add a lot of light from a short distance).
In any case you may need to use a fairly strong neutral density filter to allow slow enough shutter speeds. You can make a variable ND by stacking two linear polarizers which you can usually find used for cheap... they're not good for SLR camera's metering/autofocus systems and have largely been replaced by CPL's; but they are fine for a manual exposure/pre-focused situation like this, and they're fine for mirrorless use/cameras (i.e. live view photography).
You can also use welding glass as an ND filter, just secure it to the lens with rubber bands... #8 is about 10 stops, and #10 is about 13 stops. But it will have a strong color cast that will have to be corrected in post.
As long as your exposure is controlled there is little risk of equipment damage... the primary risk to humans is the strong UV emitted; but the glass of a lens, and the UV/IR sensor filter, eliminates most of that risk.
My first thought was that there should be a bonus for anyone who manages to write an answer that can be interpreted in multiple ways, and could either describes welding photography or wedding photography. :-)
I've never tried shooting welding, personally, so this is just a gut reaction.
My first concern would be for the safety of the camera. Welding produces light intense enough to damage your eyes, which means it can probably damage the sensor, too. To protect your gear, I would suggest using special lenses that are almost black, letting in only a tiny bit of light, similar to what folks used when shooting solar eclipses.
And if you're darkening the lens down that much, you'll also need massive amounts of light to see anything. Multiple floods pointing straight at it from as close as people can deal with might work, but the best approach would probably be to shoot outside at high noon and use multiple foil reflectors to concentrate the sunlight.
Good luck.
The difference in brightness between the normal scene and the welding arc makes this hard. I would start by asking the purpose of the photos to assess what you should do. If they are safety posters telling people not to look at the arc it is probably OK to let the welding arc blow out. Use the same settings you would use without the arc and the big blown out spot will look dangerous and get your message through. If they are publicity photos saying "look how hard and dangerous this work is" you can again let the arc blow out as it carries your message. It may offend you as a photographer to blow out some of the frame, but if the shot does what you want you should accept that.
If you want to make a photo for training welders what an arc should look like you need to make the conversion between welding shade and fraction of light transmitted, then translate that to f stops. I did some searching and failed at the first point. I found recommendations for the welding shade depending on the type of welding being done but could not change that to transmission level. You probably need an ND filter for your lens. You can then do something like HDR. Take one shot that gets the environment right and one shot with much lower exposure that gets the arc right, then load them as layers into Photoshop and mask the top layer to only cover what it should.
Sometimes, when I try to give an answer to a question, I end up with more questions.
Is a welder the primary focus of the shot? Or is it a big welding machine with an operator?
Are the photos instructional, so you need to see the proper position of the hands, distance to the weld, etc?
I could ask a bit more, but I am assuming some of that.
If you have a bright spot compared to other zones of the image, you can do one of two things.
Lower the intensity of the bright part or pump the light on the darker zone.
As the first option is (almost) out of the question, the thing to do is to pump the light on the other zones.
Use a flash
You can have it on camera bounced somewhere, or for more pleasant and controlled lighting, remotely triggered. This option could mean having an assistant holding the flash.
An assistant can be also useful for not shooting it into the eyes of the worker, so you do not distract him.
That will automatically balance the lighting on the scene.
One obvious thing is that the welding is already lighting the worker's face, so use the flash to illuminate him as a ring light, or sidelight.
Probably to illuminate the background, to give context to the scene, to the place.
Speed
Now, we must think of the aesthetics of the photo. Do you want to see sparks as dramatic lines? you need to use a slow shutter speed. Try 1/15s - 1/2s. You probably should configure the flash as rear sync. But I think is not too important.
Aperture
This again depends on the aesthetics. As in all portrait photography, you can have a wide aperture so you blur the background.
ND filter This is very important. As you are probably not using the aperture to control the light, you need to reduce it, especially with a combination of high aperture and slow speed. You need a high number ND filter (Probably 1000).
Preparation
A very important step.
As you are involved in the project, you could set up a safe place to put a tripod, and determine the distance, therefore determining the focal length you need.
You need to previously determine the focus because once a filter is on, you can barely see.
Communication
This is the most important step. For safety, but also to get the results, even if you do not have a flash or ND filter.
You can instruct the welder to only deliver a super short spark, and stay in position for one instant more. That way you could use a bit longer exposition with no extra spark illuminating the scene.
You can also sync the "action" with the "camera", so you do not need to look at the spark yourself.
You can also have time to let the smoke disapear.
Remember that I said that it is almost out of the question to reduce the intensity of the light? If the photo is only for promotional purposes, you can obstruct the bright spot itself with a prop or choose a different angle.
Know your settings
It have being ages since I did that. But you should make some tests to determine the useful EV settings and combinations with the ND filter, and exposure times.
Start with very safe values for the sake of your sensor. Low aperture, and 1/125 s (thinking of implementing a normal flash). If you need faster shutter speeds, like 1/1000, think about an HSS flash. (But people have been taking photos of welding before that technology)
If you have a mirrorless camera, do not leave it with the live view on. I would prefer an optical viewfinder. But that is just me.
Post
Remember. If you shoot in RAW, you can compensate a bit on post, lifting the dark areas. Just do not blow the white zones of the weld. You even can find details you did not notice before.
