Digital camera type for welding and oxy cutting?

[Grahame Collins]

Hi Guys,
If I may be so bold,I would ask a question of you?
Those of you that know me,will recognize my name name from the metalwork forums.

My question concerns photographing the oxy cuttin process with a digital camera. I have tried to photograph the lighted torch (flame) with the aged school Sony Mavica camera.

While the Mavica gives very good results in other close ups ( thats macro isn't it?) - all that I can manage to do is get a rather flared image of the of the flame.

What I am wanting to do is obtain a clear photo of the flame and the spatial relationship of how close it must be to the plate to be oxy flame cut.

Naturally ,this is not satisfactory when the flame image is all blurred ,fuzzy and renders no visible image at all, of what I want to display.

Down the track, at around retirement time or there abouts I will purchase a camera with these capabilities. I wish to produce a DVD or CD to provide for schools,the basics on stick welding, Mig welding and Oxy cutting and brazing /silver soldering. Thats the sort of work I have in mind for such a camera.
Is some kind soul able to tell the sort of digital camera make and model,that I should be asking for?

Thanks in anticipation,
Grahame Collins

[Ianab]

Tricky.

The problem is the welding/cutting flame is about 1000 times brighter than surrounding stuff.

Sorta like trying to take a photo of the sun.

Only thing I can thing off is to take two pics, one over exposed and one under, then combine them digitally with photoshop. Same idea as with the Lunar eclipse pictures.

Cheers

Ian

[Big Shed]

The problem you are experiencing is overexposure, the camera probably cannot stop down the lens enough and/or set a fast enough shutter speed.

So what you have to do is cut down the amount of light entering the lens. You can do that by putting a neutral density filter on the lens (ND4 or ND8) or even using a polariser, that will have the effect of an extra 2 f stops.

Hope that is clear, if not please feel free to ask.

[Harry72]

Try putting a white back ground behind the flame?(it may help the camera exposure settings)

[Grahame Collins]

Thanks Gentlemen,
Please understand that with a camera I am the complete bumbling amateur mumby. I did and still own a Canon 35mm T50 SLR and found it relatively easy to drive ,but these digital doohickeys are a whole new can of worms for me.

I will try the white background thing.

I don't think the Sony Mavica can accept another lens ,it appears that it is fixed, or can the other lenses friction fit over the existing one.?

I suspect what you are really saying that is I will have to go to one of those SLR digital cameras. Ones that take attached lenses as the Canon did. That is no problem.I would expect to use the new camera for near and close up work to illustrate my CD's.
I expect of course to spend some serious money but as this will illustrate some professional work I am seeking a quality unit. I am expecting to offer the CD,s to most high schools in the country

I would prefer to be guided by friends here than some sales shark at the camera shop.
Thanks again
Grahame

[Master Splinter]

Just sticky tape a normal welding filter over the lens as a test.

Way too much light can throw off the autofocus (not enough edge detail for the autofocus to work on) which could explain the blurryness. You may need to set the focus manually. (A tripod will help).

Could also be the amount of infra-red light - unlike the human eye, digital cameras are sensitive to infra-red and this could throw it off (focuses at a different point). I think the normal welding filters will cut this down.

If you are trying to get more of the surrounds in, the easiest way to do it without doing double exposures (which may not work as there may be too much light flare from the flame) is to simply bring in a half dozen 500 watt floodlights and increase the amount of light on the surrounding area. Yes, it will be hot under all those lights, but think of it as pre-heating the weld area! (or do a quick test outside on a sunny day to see if that improves things).

[Grahame Collins]

Onya Boys

You are all plurry geniuses.

I will give him a try.

Ta Muchly
Grahame

[echnidna]

wonder how you'd go using a camera with an auto arc welding mask

[bsrlee]

You may also find that the digital sensor has a problem with bright point light sources - the older cameras alway had a fit when photographing candles, and you got a streak across the image - usually vertical.

My old Mavica also had focus problems at times as well as the above, the new Sony doesn't (fingers crossed).

If you are going to buy a new camera for a specific purpose & its a fair bit of $$$, see if you can 'borrow' a demo model (on 'deposit')from the retailer or importer to test - assurances from sales men change with the wind, and they will be reluctant to put anything in writing.

[joe greiner]

The "film" for digital cameras is so cheap, you can afford to experiment a lot. Use a tripod for support, so you can combine pics as Ian suggests.

With arc welding, you may need to use full manual mode for exposures anyway. High electromagnetic fields can drive the camera's exposure circuitry nuts. Years ago (before digital), I took some pics in the generator room at Hoover Dam in Arizona; the needle wouldn't stand still. Pics came out OK, though.

Joe

[Ianab]

Yup, whatever you end up with make sure it has full manual controls for exposure and focus, and a decent optical zoom so you can keep the camera away from the smoke and sparks. Most of the cheaper digicams just have auto settings and wont know what to make of the lighting in a welding scene.

I have a Sony H7 camera that would probably do what you want. It's not a SLR, but it does have full manual settings option for everything. Means you can deliberatly under or over expose shots to highlight what you need to see.

The idea of welding under a couple of 500w floods would probably help too.

Here are a few pics to show what I mean. Not having a welder here in the lounge I used a halogen desk lamp as a subject.

Number 1 is the little desk lamp, just shot on auto. The lamp itself is totally overexposed as you would expect. F2.7, ISO 320, 1/40 sec was what the auto mode decided on.

2nd is the same sceen with manual settings F4, ISO 100, 1/2500 sec set manually.

3rd is a crop of the 2nd pic to show the detail.

4th pic is getting up close and personal with the lamp, just on auto again.

With a full auto camera shot one is all you are going to get.

Cheers

Ian