photo and video welding

[Broccoli1]

Sorry, the shutter speed vs. aperture was my mistake.

Dave

Dave you had it correct- changing the aperture will change the Depth of Field

Shoot the 1st shot at say f8 and whatever shutter speed (fast) to get the exposure for the Arc.

Shoot the 2nd shot at f8 and then whatever shutter speed (slow) to get the exposure for the surrounding area.

[Broccoli1]

Here it is

[Rocky D]

So easy, a cave baby could do it!

[Sully2]

Who has done closeup work with welding? We tried a couple filter plates but there is huge improvements needed, anyone done this or know someone who has?

You need a center weighted neutral density filter(s). A light reading ( using a hand held light meter) of the ambient light..AND of the "spark" of the welding operation. By comparing the two, that tells you how many stops of filter you need to cut the center portion ( the sparc) down.

It looks like from the "rays of light" that are spurious in the pics..you may also need a polarizing filter.

If the difference in "stops" are too drastic..you will need BRIGHT lights to bring UP the light of the "background".

If you dont have a SLR ( digital or film) that you can set to fully manual...adjusting shutter speed / apeature based on the light readings and the "film" ISO...basically...your screwed!

[JimYo]

my daughter took this one with some sun light and the arc hidden a little by the vicegrip... nikon with no filter
Jim

[enlpck]

I'v had some success with a point-and-shoot digital using a gold filter in from of the lens, forcing the focus (setting for macro and positioning at the maximum distance for the macro setting) and using LOTS of extra light... several halogen heads, for example.

The camera I use picks exposure from the center of the frame, so I can either force the exposure to show the arc and pool (sort of), or the background, depending on if I aim dead on or a little off center.

No pics handy on this computer... I'll see if I can find some later.

[Sully2]

my daughter took this one with some sun light and the arc hidden a little by the vicegrip... nikon with no filter
Jim

Yepper! Sunlight brought up the ambient light..but of course the welding arc is still FAR over exposed

[Sberry]

I am familiar with the basics of photography, the ideal thing for us would be to do macro video of actual puddle. I was considering gold lenes also but didint have a large one around, might try an 8 in that.

[DrIQ]

As suggested setup several halogen lights to add to the ambient light.

For your filter use a light oxy filter lens as your primary and then cut a small round secondary filter shade 10 at a diameter to cover the actual arc and center it on the oxy filter. You will be able to see the weld puddle very well using this process.

The challange is getting the secondary filter the right diameter to just cover the arc.

The process worked well for the welding process training films that were made at the Hobart Institute 30 years ago.

[Sully2]

I am familiar with the basics of photography, the ideal thing for us would be to do macro video of actual puddle. I was considering gold lenes also but didint have a large one around, might try an 8 in that.

The welding DVD I have here shows that. The instant the arc is struck..the lights go totally dark...and thus the "proper exposure" is based on the arc light itself. Shows clearly.. As soon as the arc STOPS...the ambient lighting comes back on