DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   Photon Management (https://www.dvinfo.net/forum/photon-management/)
-   -   White balance beginner mistakes (https://www.dvinfo.net/forum/photon-management/517834-white-balance-beginner-mistakes.html)

Brian Drysdale July 23rd, 2013 10:44 AM

Re: White balance beginner mistakes
 
These days I tend to just use the pre-set or fool the camera's white balance to get the look I want. An alternative is to go into the camera's menu and set up the colour temperature there. I use the monitor to see if the colour in the scene is the way I want - slightly coloured shadows add interest and painter's use that in their work.

Once set I tend not to change the white balance.

Steven Digges July 24th, 2013 12:18 PM

Re: White balance beginner mistakes
 
I have several “tools” for white balancing. Everything from the cards that come with some Porta Brace bags to my go to tool for the last few years. A heavy duty white table cloth I keep in my big case. It is non reflective and can be folded up small or big enough to use at a distance. I can also use it for padding in a case. I like it so much I added a commercial white napkin that came with a ballroom diner, so I have a smaller one. Yes there is a benefit to being forced to eat another bad piece of chicken while sitting at a technicians table. Neither the table cloth or the napkin came with directions and I can’t even find the PDF on the web?

I am in the vertical plane camp, with the light I’m shooting in. Why a manufacturer would say keep light off the card sounds stupid to me. And here is one nobody mentioned yet. After I fill the frame with white I pull the camera out of focus before pushing the button. It evens out the white surface. That’s probably very old school, but hey, it is the way I was trained.

Also, I would caution people against using I-pad apps. Just because they exist does not mean they are good. I have one. It has about 40 “cards” in it. I would never use it to set a camera though. It does not make sense to me to shoot a light source or a reflective surface for balance. An I-Pad is both.

Steve

Al Gardner July 24th, 2013 02:04 PM

Re: White balance beginner mistakes
 
Steve,
All I want to know is where did you get the tablecloth from?

I seem to have had one jump into my bag before.

Josh Bass July 24th, 2013 02:49 PM

Re: White balance beginner mistakes
 
Wouldnt the ipad screen be 5600k no matter what color it was showing?

Al Gardner July 24th, 2013 06:36 PM

Re: White balance beginner mistakes
 
Why would that be?????????

Josh Bass July 24th, 2013 07:30 PM

Re: White balance beginner mistakes
 
I was thinking just cause it's a screen? I haven't tried it with an ipad specifically but if you ever try balancing on a TV/Projector screen, etc. you find that regardless of what's on the screen, your balance is somewhere in that blue family. Maybe it's different with whatever an Ipad uses.

Tom Morrow July 25th, 2013 03:01 AM

Re: White balance beginner mistakes
 
Since the ipad is a light source instead of reflector it would be useless for measuring/calibrating the light falling on the subject. I assume the idea behind the ipad whibal is to allow you to get presets that your camera doesn't expose.

I love Steve's idea of using a formal tablecloth/napkin for target. So long as you verify that it's really white by photographing next to a real white card, big is better. I suspect that small targets are the cause of many whibal errors as people have to move the card closer to the camera than subject position, in order to fill the sensor frame. These days with everyone shooting primes, zooming is often not an option.

James Kuhn July 25th, 2013 12:15 PM

Re: White balance beginner mistakes
 
I'm looking for 'Linen Table Clothes', too. : )

Regards,

J.

Garrett Low July 25th, 2013 12:30 PM

Re: White balance beginner mistakes
 
Quote:

Originally Posted by James Kuhn (Post 1806058)
I'm looking for 'Linen Table Clothes', too. : )

Regards,

J.

Just be careful. Most "white" fabric is not white. If you are truly concerned about white balancing I think it's worth it to invest in a white card or something like the fold out white cards and shoot a few seconds of the card after you do your manual WB. As I said, I also like to have a few seconds of a color reference card.

But I have used just about anything white to get a close read on the color temp then I tweak to what I'm seeing.

As an aside, I worked with a famous interior designer who wrote a book about how there were 200 different colors of white. I'd say that's a little overboard but then again, he was the one who was famous.

Steven Digges July 25th, 2013 01:17 PM

Re: White balance beginner mistakes
 
Tom & Garrett,

How white does white need to be? There are three threads we are all working on and it is getting a little confusing. I think I need the time to read them all again in one sitting. I am particularly confused about the white to grey issue. I always use white, but I want to understand all of this better so I will reread it all later.

So….I got out the table cloth, napkin, Porta Brace white card, Adobe white card, and Adobe grey scale card. They are all white but all different. Do these subtleties matter? Scientifically speaking I’m sure they do. Realistically I doubt it? Some of you are saying you can go all the way to 18% grey and pull a white balance? That is the part I need to reread.

Zebras came up, another thing I have been using for 20 years. I like them, I use them, I set them depending on each type of scene. I never thought I would ask a forum question about a simple tool I thought I knew. My latest camera has a setting for 100+, what the hell is that? Are they saying that at a perfect 100 you have not technically clipped yet but 100+ everything showing is clipped? Zebras are a guide for me, one of several things I use for exposure, not the least of which is experience and taste.

Al, you asked where I got the table cloth. I produce corporate audio visual events as well as corporate videos. Procuring the table cloth involved being nice to a ballroom captain…………..but I am always nice to the people who control the food! All jokes aside, it is a great white balance tool.

Brian Drysdale July 25th, 2013 01:59 PM

Re: White balance beginner mistakes
 
I know that when taking a white balance from various type of "white" paper, a broadcast camera will give different colour temperature readings. Some are "cooler" or whiter looking than others, you can see the difference when placed side by side.

BTW The director's script or schedule often gets used for white balancing.

Seth Bloombaum July 26th, 2013 09:34 AM

Re: White balance beginner mistakes
 
Quote:

Originally Posted by Steven Digges (Post 1806076)
,,,Some of you are saying you can go all the way to 18% grey and pull a white balance? That is the part I need to reread.

Zebras came up, another thing I have been using for 20 years. I like them, I use them, I set them depending on each type of scene. I never thought I would ask a forum question about a simple tool I thought I knew. My latest camera has a setting for 100+, what the hell is that? Are they saying that at a perfect 100 you have not technically clipped yet but 100+ everything showing is clipped? Zebras are a guide for me, one of several things I use for exposure, not the least of which is experience and taste....

The point about 18% grey is that it is widely available, neutral in tint, and bright enough that a cam will not reject it. In the WB process the cam is, um, setting a neutral point between magenta & green, IIRC. So nearly any neutral source between white and middle gray can be used.

As Brian wrote, so many tints of white are available. A purist wouldn't like that... Me, I just try to be careful when using the nearest piece of white paper that it isn't translucent under the light and showing through some skin tones of the person holding it.

What cam shows 100+ as a zebra setting?

We're used to thinking about 0-100% as the luminosity scale, but it isn't. It's -20 to +120 IRE, with detail in the range of 7.5 to 110 IRE. But that was from analog standards. DV went 0-110.

There are some post tricks to pull detail from 100-110, you'd be surprised, sometimes there is detail there!

100+ probably just means the obvious of 100 percent or IRE or above. Maybe there is detail.

But all Zebras refer to ranges...

Tom Morrow July 27th, 2013 01:58 AM

Re: White balance beginner mistakes
 
The color white (or gray) that you want is the one that reflects the light with the same spectral balance as the incident light. There is only one such color, but many may be sufficiently close. Generally high quality copy paper is pretty close, although age and other factors mean it's not reliable to use a random piece of paper.

Tom Morrow July 27th, 2013 02:01 AM

Re: White balance beginner mistakes
 
Quote:

It should be aimed about 45 degrees up, to reflect the sun or whatever the dominant light source is. Theoretically matte surfaces don't need to be aimed but in practice they do.
I shouldn't have said 45 degrees... that was from a poor example of when the light to be balanced was directly overhead like a sun at noon. Good light usually isn't directly overhead.

Instead of 45 degrees, I suggest the angle at which a mirror would reflect the light directly into the camera lense. If a light is 30 degrees above horizontal, then the card should be angled half that, 15 degrees, up from vertical. That's how I really do it in practice, typically 10-20 degrees tilt.

The thorny question is what angle to use with mixed light when your intention is to have the higher temp light go somewhat blue and the lower to go somewhat orange. I am starting to think that custom white balance should be avoided in significantly mixed temp lighting, because you will get essentially random results depending on what angle you hold it. And you might see measurement shift as you move the target about if the lights don't have exactly the same coverage.

Since the goal is to get your shots consistent, and since you get very random results balancing in mixed light, perhaps it's best avoided and presets should be used (ideally consulting a calibrated monitor).

Steven Digges July 27th, 2013 10:07 PM

Re: White balance beginner mistakes
 
The one camera I have with zebra settings from 70 to 100+ is a Sony EA50.


All times are GMT -6. The time now is 09:36 PM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2025 The Digital Video Information Network