White balance at DVinfo.net

Go Back   DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XL and GL Series DV Camcorders > Canon GL Series DV Camcorders

Canon GL Series DV Camcorders
Canon GL2, GL1 and PAL versions XM2, XM1.


Reply
 
Thread Tools Search this Thread
Old March 9th, 2004, 04:28 AM   #1
New Boot
 
Join Date: Nov 2003
Location: Belgium
Posts: 22
White balance

Hey all !

I'm a new owner of an XM-2 and so far I'm impressed. My previous camcorder was a Sony Hi8 and it was pretty old :)

I was messing around a bit with custom white balance yesterday, using a white sheet of paper. But if I understand correctly, it would be better to white balance with a 18% gray card. Somehow I don't understand how you can "white" balance with a gray card. So could someone explain this to me, or am I just wrong? :)
Kris Verstappen is offline   Reply With Quote
Old March 9th, 2004, 04:46 AM   #2
Trustee
 
Join Date: Dec 2002
Location: Gwaelod-y-garth, Cardiff, CYMRU/WALES
Posts: 1,215
Always white balance with white! (well, there are some little tricks you can play with non-white materials, but that's not relevant here) Just make sure that it's not over-exposed when you try to balance.

Robin.
Robin Davies-Rollinson is offline   Reply With Quote
Old March 9th, 2004, 04:55 AM   #3
New Boot
 
Join Date: Nov 2003
Location: Belgium
Posts: 22
Thanks for your answer, Robin.

So if I get it right: gray cards are then only used for light metering. Especially in photography I suppose.

What do you people use for white balancing? Normal paper? Sheep? ;)
Kris Verstappen is offline   Reply With Quote
Old March 9th, 2004, 06:23 AM   #4
Warden
 
Join Date: Mar 2002
Location: Clearwater, FL
Posts: 8,267
A grey card contains equal parts of red, green and blue. You can WB to a grey card and many people do to avoid the over exposure problem Robin mentions. You will get color shifts if you WB to colors that do not contain equal parts of R, G, and B.
__________________
Jeff Donald
Carpe Diem




Search DVinfo.net for quick answers | Where to Buy? From the best in the business: DVinfo.net sponsors
Jeff Donald is offline   Reply With Quote
Old March 9th, 2004, 08:32 AM   #5
New Boot
 
Join Date: Nov 2003
Location: Belgium
Posts: 22
Ah great! Like that it does make sense. Thanks to both of you again.
Kris Verstappen is offline   Reply With Quote
Old March 9th, 2004, 02:50 PM   #6
Trustee
 
Join Date: Apr 2002
Location: Auckland, New Zealand
Posts: 1,727
But Jeff, aren't you still telling the camera that gray is now white, so anything looking like that grey card will come out white? And so whites will be, well, not white...or "too" white?.

Aaron
__________________
My Website
Meat Free Media
Aaron Koolen is offline   Reply With Quote
Old March 9th, 2004, 02:59 PM   #7
Warden
 
Join Date: Mar 2002
Location: Clearwater, FL
Posts: 8,267
White is only a mixture of R, G, and B, as is black. The absolute value of white is a product of exposure (aperture, shutter speed and gain). You can WB to any shade of grey, as long as the R, G and B components are of equal value.
__________________
Jeff Donald
Carpe Diem




Search DVinfo.net for quick answers | Where to Buy? From the best in the business: DVinfo.net sponsors
Jeff Donald is offline   Reply With Quote
Old March 10th, 2004, 01:24 AM   #8
Old Boot
 
Join Date: Aug 2002
Location: London UK
Posts: 3,528
. .Just as an aside here . . I recently went to a WB workshop where the "lead" demonstrated the use of a Blue lighting gel placed in front of the lens while WBing to make the shot warmer & reddish . . it worked very well .. Of course I as impressed . . I think others there knew about this "trick" . . BUT, and this is my point, it really drove home to me the value of correct WBing AND where the rules could be broken, for an effective result - yeah?

Grazie
Graham Bernard is offline   Reply With Quote
Old March 10th, 2004, 01:35 AM   #9
Trustee
 
Join Date: Dec 2002
Location: Gwaelod-y-garth, Cardiff, CYMRU/WALES
Posts: 1,215
That's what I meant in my previous post about various little tricks....
Getting back to what type of card, I have never used or seen used a grey card for balancing. In the day job, I use - or if I'm directing, someone else is using - various cameras from dcvam, digibeta to hi-def and we all use a white card. Sometimes it's just a sheet of paper on the PA's note pad.
Any major colour grading is going to be done in post anyway!

Robin.
Robin Davies-Rollinson is offline   Reply With Quote
Old March 10th, 2004, 01:52 AM   #10
Old Boot
 
Join Date: Aug 2002
Location: London UK
Posts: 3,528
. . and this is what Robin "touched-on" in the his previous post . . [ I knew I should have added this ;-) . . . ]

. . The other thing this chap mentioned was that there is no such thing as a colour camcorder . .they are all black and white . .with colour "filters" and they are R,G,B . . . that helped me too .. .

Cards and their "hue" are very important. They are important as a small swing away from the "numbers" can give large chaanges in what you record . . . I've was told by a pro that he WBed straight at a lamp! I would not do it .. . seems a bit drastic . .

Robin, I think some "numbers" are in order here . .yes? What are the numbers and values of R,G,B? Wouldn't this assist? . . This is my "hamfisted" attempt to put some science into the discussion - yeah?

Grazie
Graham Bernard is offline   Reply With Quote
Old March 10th, 2004, 02:04 AM   #11
Trustee
 
Join Date: Dec 2002
Location: Gwaelod-y-garth, Cardiff, CYMRU/WALES
Posts: 1,215
Take a look at this: http://www.help4web.net/webmaster/Color/RGB-Values.html
for values of "different" whites, as well as some other colours!

Robin.
Robin Davies-Rollinson is offline   Reply With Quote
Old March 10th, 2004, 02:13 AM   #12
Old Boot
 
Join Date: Aug 2002
Location: London UK
Posts: 3,528
Robin! That's brilliant! And so fast too . . I'm very impressed . . . I've seen this information in various ways but never so beautifully outlined and easily viewed. . It's a real pleasure to scan through it .. thanks for sharing your knowledge . .

The one thing a immediately scanned was the examples of "white" and the numbers it is made from . .

Thanks again,

Grazie
Graham Bernard is offline   Reply With Quote
Old March 10th, 2004, 06:36 AM   #13
Warden
 
Join Date: Mar 2002
Location: Clearwater, FL
Posts: 8,267
Those colors are only a starting point. The colors mixes they are purposing are not correct for NTSC or PAL video. The site is for web designers and RGB values can be very different from NTSC colors. The site lists black as 0, 0, 0, but for video it is 16, 16, 16.

The problem with white balancing off paper and other products is they contain optical brighteners, which contain a large blue component. The use of grey cards (18% grey used for film exposure) has been discussed extensively here in the past. Do a search on grey cards (gray) and you'll find various detailed discussions on the matter. Custom WB cards has also been discussed.
__________________
Jeff Donald
Carpe Diem




Search DVinfo.net for quick answers | Where to Buy? From the best in the business: DVinfo.net sponsors
Jeff Donald is offline   Reply With Quote
Old March 10th, 2004, 07:38 AM   #14
Old Boot
 
Join Date: Aug 2002
Location: London UK
Posts: 3,528
Hmmm .. I wonder if Robin noticed this too .. I do hope so . . . interesting . . Thanks for the "warning" that this list is a starting point. Of course the other thing is that we are all "viewing" whatever colours through a whole range of decoding devices . . CRTs and LCD TFTs and goodness knows what else! . . ..

Thanks for the Heads-Up on this Jeff,

Grazie
Graham Bernard is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XL and GL Series DV Camcorders > Canon GL Series DV Camcorders

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 03:01 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network