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Science Forum Index » Engineering - Joining (Welding) Forum » Cameras for welding
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| Ipeak |
 Posted: Tue Jan 02, 2007 3:09 pm |
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| Ernie Leimkuhler |
| Posted: Wed Jan 03, 2007 2:19 am |
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In article <1167764986.418388.156700@h40g2000cwb.googlegroups.com>,
"Ipeak" <pgtaw@hotmail.com> wrote:
Some of these are very cool, but way too much $.
I just need to figure out how to rent or borrow one. |
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| Potblak |
| Posted: Wed Jan 03, 2007 3:14 am |
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Just use a regular camera and shoot through a #13 lens and filter
Workd fine! Been using it for years. Film AND digi.
"Ipeak" <pgtaw@hotmail.com> wrote in message
news:1167764986.418388.156700@h40g2000cwb.googlegroups.com...
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| Richard Smith |
| Posted: Wed Jan 03, 2007 5:28 am |
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Ernie commented
Quote: Some of these are very cool, but way too much $.
I just need to figure out how to rent or borrow one.
and
"Potblak" <Invalid@Invalid.net> writes:
For Ernie - Simple logical point, surely:
These "fancy" methods including the "narrow-pass filter" are to remove
the arc from the picture and see the metal transfer and liquid metal
behaviour. Product development tool.
That isn't what someone welding sees. What the weldor sees is the
point of the video. So the big-$$$ systems aren't at all the thing
here.
With a clean welding filter of the correct grade, you see the weld
area in colour vision. Surely the assistance you need is from a
friendly experienced photographer - they know how to use filters and
use them all the time to manipulate what becomes the "point" of a
picture, don't they?
I remember a photographer saying about a metallographic specimen "If
you can see it, we can photograph it".
Richard Smith |
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| Ernie Leimkuhler |
| Posted: Wed Jan 03, 2007 10:25 am |
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In article
<459b57bd$0$2608$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
"Potblak" <Invalid@Invalid.net> wrote:
Quote: Just use a regular camera and shoot through a #13 lens and filter
Workd fine! Been using it for years. Film AND digi.
Source?
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| John Husvar |
| Posted: Wed Jan 03, 2007 11:04 am |
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In article <stagesmith-E12A65.22194702012007@news.west.earthlink.net>,
Ernie Leimkuhler <stagesmith@mindspring.com> wrote:
Ernie,
Hope I'm not telling you something you already know.
Before you go to the expense of renting one of those, try putting one or
two neutral density filters in front of the lens. You can get them at
any decent photography supply. They're usually in 1/3 stop increments.
(or were lo, these many years ago) They preserve color very well,
having no color bias.
You can get them as gels and a gelholder isn't very expensive. To avoid
heat damaging them, can you shoot from a few feet away and zoom in?
http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/filter/filter-ND.html
Would that help?
--
Bring back, Oh bring back
Oh, bring back that old continuity.
Bring back, oh, bring back
Oh, bring back Clerk Maxwell to me. |
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| Grant Erwin |
| Posted: Wed Jan 03, 2007 12:56 pm |
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Ernie Leimkuhler wrote:
Quote: In article
459b57bd$0$2608$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
"Potblak" <Invalid@Invalid.net> wrote:
Just use a regular camera and shoot through a #13 lens and filter
Workd fine! Been using it for years. Film AND digi.
Source?
I read that to mean a regular welding filter in shade #13. Maybe I got it wrong.
GWE
--
Posted via a free Usenet account from http://www.teranews.com |
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| Potblak |
| Posted: Wed Jan 03, 2007 7:56 pm |
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"Grant Erwin" <grant@NOSPAMkirkland.net> wrote in message
news:459bd372$0$4775$88260bb3@free.teranews.com...
Quote: Ernie Leimkuhler wrote:
In article <459b57bd$0$2608$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
"Potblak" <Invalid@Invalid.net> wrote:
Just use a regular camera and shoot through a #13 lens and filter
Workd fine! Been using it for years. Film AND digi.
Source?
I read that to mean a regular welding filter in shade #13. Maybe I got it
wrong.
You got it right. |
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| Ernie Leimkuhler |
| Posted: Thu Jan 04, 2007 12:39 am |
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In article
<jhusvar-9B79D9.10041703012007@newsclstr03.news.prodigy.net>,
John Husvar <jhusvar@sbcglobal.net> wrote:
I will try it.
I am going to try a few different gel filters, like cobalt. |
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| Martin H. Eastburn |
| Posted: Thu Jan 04, 2007 11:51 pm |
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Why can't you put the camera behind a gold welding wall ?
Color will be shifted - but won't it cut the light back
to the extent you need ?
Seems like it works for people eyes, it should work for you.
My telescope uses a gold cover for the front of the tube so to look
at the sun. From there the eye or the camera is aok.
Martin
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/
Ernie Leimkuhler wrote:
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----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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| Ernie Leimkuhler |
| Posted: Fri Jan 05, 2007 12:07 am |
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In article <1167969186_39577@sp6iad.superfeed.net>,
"Martin H. Eastburn" <lionslair@consolidated.net> wrote:
Quote: Why can't you put the camera behind a gold welding wall ?
Color will be shifted - but won't it cut the light back
to the extent you need ?
Seems like it works for people eyes, it should work for you.
My telescope uses a gold cover for the front of the tube so to look
at the sun. From there the eye or the camera is aok.
Martin
The problem is that a gold or tinted welding curtain doesn't filter
enough light, and a welding hood blocks too much.
What I am going to work on are cobalt filters, color correction filters
and high-pass filters.
The idea is to block the unwanted wavelengths, while leaving the correct
ones.
The human eye is an amazing instrument, capable of an enormous range of
light perception.
My camcorder is a simpler beast. |
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| Pete Keillor |
| Posted: Fri Jan 05, 2007 9:02 am |
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On Fri, 05 Jan 2007 04:07:17 GMT, Ernie Leimkuhler
<stagesmith@mindspring.com> wrote:
Quote: In article <1167969186_39577@sp6iad.superfeed.net>,
"Martin H. Eastburn" <lionslair@consolidated.net> wrote:
Why can't you put the camera behind a gold welding wall ?
Color will be shifted - but won't it cut the light back
to the extent you need ?
Seems like it works for people eyes, it should work for you.
My telescope uses a gold cover for the front of the tube so to look
at the sun. From there the eye or the camera is aok.
Martin
The problem is that a gold or tinted welding curtain doesn't filter
enough light, and a welding hood blocks too much.
What I am going to work on are cobalt filters, color correction filters
and high-pass filters.
The idea is to block the unwanted wavelengths, while leaving the correct
ones.
The human eye is an amazing instrument, capable of an enormous range of
light perception.
My camcorder is a simpler beast.
How about a Nexgen on the grinder setting?
Pete Keillor |
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| John Husvar |
| Posted: Fri Jan 05, 2007 9:24 am |
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In article <stagesmith-B2B148.20074304012007@news.west.earthlink.net>,
Ernie Leimkuhler <stagesmith@mindspring.com> wrote:
Quote: In article <1167969186_39577@sp6iad.superfeed.net>,
"Martin H. Eastburn" <lionslair@consolidated.net> wrote:
Why can't you put the camera behind a gold welding wall ?
Color will be shifted - but won't it cut the light back
to the extent you need ?
Seems like it works for people eyes, it should work for you.
My telescope uses a gold cover for the front of the tube so to look
at the sun. From there the eye or the camera is aok.
Martin
The problem is that a gold or tinted welding curtain doesn't filter
enough light, and a welding hood blocks too much.
What I am going to work on are cobalt filters, color correction filters
and high-pass filters.
The idea is to block the unwanted wavelengths, while leaving the correct
ones.
The human eye is an amazing instrument, capable of an enormous range of
light perception.
My camcorder is a simpler beast.
One of the first lessons our color photography instructor used at Good
ol' Kent State (Yep, that one.) was to assign a set of pictures of a
color test scale. That was to illustrate how the brain "corrects" color
when a light variation isn't enough to overwhelmingly influence
perception.
He had us take the pictures with daylight balanced color slide film in;
full daylight, sunrise, sunset, indoors under tungsten lighting, indoors
under fluorescent lighting, (both with no flash) and in the darkroom
under its monochromatic safelights. (Only that one light frequency
recorded at all.)
Then he had us repeat the series with tungsten balanced film. Then he
started us on filtration, color temperature, etc.
It's pretty surprising how the brain interprets colors under various
lighting conditions. It seems to "color correct" on the premise: "That
_should_ be fleshtone, so, by golly, it's fleshtone!" You have to train
yourself to "see" (i.e. anticipate) color shift.
It's probably a good thing that happens. People's flesh looks really bad
in the old Cool White fluorescent light. They look like all that's
missing is the toe tag. Sure would reduce office romances!:)
--
Bring back, Oh bring back
Oh, bring back that old continuity.
Bring back, oh, bring back
Oh, bring back Clerk Maxwell to me. |
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| Ernie Leimkuhler |
| Posted: Fri Jan 05, 2007 11:44 pm |
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In article <v1jsp21oau25qse3osq1d6co4v55aqbjt2@4ax.com>,
Pete Keillor <keillorp135@chartermi.net> wrote:
Quote: On Fri, 05 Jan 2007 04:07:17 GMT, Ernie Leimkuhler
stagesmith@mindspring.com> wrote:
In article <1167969186_39577@sp6iad.superfeed.net>,
"Martin H. Eastburn" <lionslair@consolidated.net> wrote:
Why can't you put the camera behind a gold welding wall ?
Color will be shifted - but won't it cut the light back
to the extent you need ?
Seems like it works for people eyes, it should work for you.
My telescope uses a gold cover for the front of the tube so to look
at the sun. From there the eye or the camera is aok.
Martin
The problem is that a gold or tinted welding curtain doesn't filter
enough light, and a welding hood blocks too much.
What I am going to work on are cobalt filters, color correction filters
and high-pass filters.
The idea is to block the unwanted wavelengths, while leaving the correct
ones.
The human eye is an amazing instrument, capable of an enormous range of
light perception.
My camcorder is a simpler beast.
How about a Nexgen on the grinder setting?
Pete Keillor
Not enough filtering, tried it. |
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| Pete C. |
| Posted: Sat Jan 06, 2007 12:18 am |
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Ernie Leimkuhler wrote:
Quote:
In article <v1jsp21oau25qse3osq1d6co4v55aqbjt2@4ax.com>,
Pete Keillor <keillorp135@chartermi.net> wrote:
On Fri, 05 Jan 2007 04:07:17 GMT, Ernie Leimkuhler
stagesmith@mindspring.com> wrote:
In article <1167969186_39577@sp6iad.superfeed.net>,
"Martin H. Eastburn" <lionslair@consolidated.net> wrote:
Why can't you put the camera behind a gold welding wall ?
Color will be shifted - but won't it cut the light back
to the extent you need ?
Seems like it works for people eyes, it should work for you.
My telescope uses a gold cover for the front of the tube so to look
at the sun. From there the eye or the camera is aok.
Martin
The problem is that a gold or tinted welding curtain doesn't filter
enough light, and a welding hood blocks too much.
What I am going to work on are cobalt filters, color correction filters
and high-pass filters.
The idea is to block the unwanted wavelengths, while leaving the correct
ones.
The human eye is an amazing instrument, capable of an enormous range of
light perception.
My camcorder is a simpler beast.
How about a Nexgen on the grinder setting?
Pete Keillor
Not enough filtering, tried it.
I'd suggest to start with, get the inexpensive Sunpak UV and ND4 filter
set to fit your camcorder. The 37mm set for my little camcorder was like
$15. Pump as much lighting into the weld area as possible from multiple
angles to eliminate shadows and reduce the extreme contrast from the
arc. Add some light shade welding lenses, like #3 and experiment until
you get decent results.
Eliminating any UV and taking things down four stops to begin with at
the camera should help a lot. The extra lighting will help with the
contrast extremes. Most importantly run the camcorder on manual iris /
exposure as well as manual focus. With the extreme contrast of the scene
the auto iris / exposure has no chance of getting the desired exposure.
On auto exposure the camera will try to adjust for the arc which is
pretty hopeless. You want to adjust for the surrounding area so it isn't
black. This will make the arc clip at peak white, but that's ok since
with a CCD camcorder that clipped area won't spill to adjacent areas
like an old tube camera would.
When I have some time I'll experiment a bit and see what kind of results
I can get in my shop.
Pete C. |
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