white balance

[homera1]

Hi ya,
can I ask all you guys that do studio work how you get your white balance?

leave camera on Auto?
set it to Flash?
set to a Kelvin figure?
Custom white balance via a card or something?

I can't seem to get consistent skin colours and it is bugging me.... I have used Auto which seemed good. Used Flash preset and it was gross.......

thanks

[Gatorboy]

What does your strobes show for white balance? My AlienBees are daylight.

But you can always shoot a gray card to get the proper white balance.

[homera1]

Sorry Gatorboy you have lost me there? my stobes don't have a white balance, there is nothing on there that indicates white balance? or am I missing something?

[steveathome]

Use custom white balance, and I recommend a WhiBal card as a reference.

I have six different grey references and only 2 of them come close to each other, WhiBal being one of them.

Edit:
I note you have a 5D, this is what I use for portraiture / studio . I also shoot in Raw, and SRGB colour space. Are all your strobes from the same manufacturer?

Also if you change a lens mid-shoot then do your CWB again.

[steveathome]

Have a look at some of the video's on this site

http://www.rawworkflow.com/index.html

I got a credit card sized one for about £20 and it took less than a week to arrive. I don't know of any other grey reference manufacturer that goes to the same effort to ensure accuracy.

[homera1]

hey thanks steveathome...... will have a look at that...
I shoot in raw and sRGB too...... but am having problems with the WB....
thanks for the tip.....

[homera1]

any one else care to share? :-)

[OneEyedJack]

if you shoot in RAW then you should be able to fully adjust your WB in your processing, but of course we all want to get it right in camera. I dont own one, but i heard the Expo Disk (http://www.expodisc.com) was great

[Jonathan H]

Not much else to say.... Steve's suggestions are what you should do.

Only the VERY expensive (~$4000 and up) units have user-controllable color temperature. Everything else tends to produce a given color temp for a given light power level. Some of the fairly expensive units (Profoto) have consistent color from lowest power up to full power.

Other lights like Alienbees, Speedotron, DynaLite (i think), and pretty much any of the more hobbyist-oriented lights will have variable color temps as you change power.

Get the WhiBal or any other certified "spectrally neutral" gray card (NOT 18% gray) and just take a quick picture with the card in the frame whenever you change lighting power, lenses, or light modifiers. Then, in post processing, all you need to do is click in the picture on the card with the grey eyedropper to get perfectly balanced white balance.

Definitely check out Michael Tapes' RawWorkflow website.... it explains everything.

Good luck!

[homera1]

thanks one eye and thanks Jonathan... I didn't know flash heads had different colour temps for different power settings..... I thought they might vary slightly, but it would be indistinguishable in the picture.... I have 5 Elinchrom EL500's... so I am hopeing they are all pretty consistent......

do flash tubes go yellower with age?

[Jonathan H]

Can't comment on the Elinchrom's, never owned them. Flash tubes eventually turn brown-ish yellow when they die. There may be a bit of yellowing over the course of their lives too, but I'm not positive either way.

Luckily, as long as you include a quick shot of a grey card each time you change your lighting setup, any changes to the color temp are irrelevant because you can compensate for them

[Gamut]

Excellent reference video! Thanks.

Have a look at some of the video's on this site

http://www.rawworkflow.com/index.html

I got a credit card sized one for about £20 and it took less than a week to arrive. I don't know of any other grey reference manufacturer that goes to the same effort to ensure accuracy.

[steve547]

Flash is usually the same color temperature as 'daylight' but only when you use the flash as your main light source. Unfortunately, none of the Canon auto setting on the camera will let you do that. You have to set the camera to manual and choose a fast shutter speed like 200 or 250 to force the ETTL-2 flash to act as your main light source. Otherwise it will act as a fill-in flash and your white balance will vary with the ambiant light in the room.

[homera1]

Oooo ... now... I may be missing something here.....

so steve547 are you saying that the camera AWB measures white balance based on the ambient light when useing stobes (and a sync cable)? even if I set the whitebalance to Flash?

I am a little bit confused how setting the shutter to 1/200th forces the ETTL-2 to act as main..... and how that fits in with Strobes?

thanks

[steve547]

If you set the camera WB to automatic, it balances the ambient light. If you set it to 'flash' , it sets the color temperature to flash(about 5500 K) and assumes you are using a flash as you main light source.
Setting the camera shutter to 1/200 second prevents the ambient light from exposing the photo since very little ambient light can get into the camera in 1/200th of a second. The camera knows this and therefore commands the ETTL flash to do all the lighting(act as the main light source). That works out well because you set the camera for 'flash' WB(5500 K), and you delivered 100% Flash(5500 K) as your only light source. If you use a slower shutter speed, then the ambient light enters the camera along with the flash and that's no longer 5500K light.

[homera1]

ahhh that explains a few things then.. I have just rechecked my pictures and the ones that are funny are set at 160th..... then the ones that are good are set to 200th.... thanks Steve547 never knew that...... :-)