White Balance with Flash

[Tweek]

Been wanting to ask about this some time ago, cos it always leaves me puzzled.

White balance corrects the colour of the light, but does it work with camera flash? I've had some problems using white balance with flash before, examples are:

This was taken with auto WB. The whole scene is reddish from the street lamps.

I tried taking this shot with tungsten WB, but the result was horrendous! The scene was lit by tungsten bulbs.

My postulation is that if the flash is strong enough to exert colour influence, then stuffs like fluorescent or tungsten WB won't work. And if the ambient light has got more colour influence, then auto WB won't work. But til now, I still have not master the knowledge of when to use what.

Anyone can help?

 

[mpenza]

for my casio cam, I use sunlight white balance as adviced by the manual. it works well.

 

[Goondu]

Most digicams do not have sophiscated algorithms to calculate the AWB.

Refer to this thread for some insight:

http://www.dpreview.com/learn/Glossary/Digital_Imaging/White_Balance_01.htm

 

[Tweek]

thanks, but why is it that when I use tungsten WB (with flash) under tungsten lightings, I get bluish cast?

 

[HOCL]

I always use the "cloud" setting on my C700 ... I like the flesh tones with this setting (with or without flash) ... I rarely have to bother with the WB setting ...

 

[ckiang]

Originally posted by Tweek
thanks, but why is it that when I use tungsten WB (with flash) under tungsten lightings, I get bluish cast?

Different colour temperature of the tungsten lights. You probably have much "bluer" tungsten lights (perceived as "not as yellow"). Halogen lights fall under this category.

I use AWB most of the time on my Coolpix. 2+ years and it still has not failed me.

For mixed lighting, you just have to decide on what's the primary light source to WB to.

Regards
CK

 

[mpenza]

Originally posted by Tweek

My postulation is that if the flash is strong enough to exert colour influence, then stuffs like fluorescent or tungsten WB won't work. And if the ambient light has got more colour influence, then auto WB won't work. But til now, I still have not master the knowledge of when to use what.

Anyone can help?

you're right to say that the flash is strong enough to exert color influence.... especially when you're using a powerful external flash. my camera's manual advised to set the WB to sunlight for the flash, whatever the ambient lighting conditions.

 

[konei]

Originally posted by Tweek
thanks, but why is it that when I use tungsten WB (with flash) under tungsten lightings, I get bluish cast?

The fact is that tungsten is always yellowish. So to compensate for the yellow cast, the camera will choose an opposite to compensate for the yellow so that the yellowish tinge becomes white. In this case, the opposite of yellow would be bluish. Look at the Photoshop colour balance to see the opposing colours.

Either way, if you have mistakenly taken the picture with a wrong WB and cannot take the picture again, you can use photoshop to correct it.

 

[konei]

Forget to say that since the flash is more powerful than the tungsen lighting you have, the flash colour will dominate plus the colour compensation to shift the yellow which is more in the blue region. Also the flash may not be as pure white as you would like.

 

[Tweek]

ok...I think I've got it, thanks for all the help. Maybe next time I should use auto or sunlight WB, plus my external flash for indoor people shots, think the result should be better.

konei, I tried correcting the "red" pic in my first post in photoshop, didn't succeed...maybe I'm too lousy in PS.

 

[konei]

Use this link. http://www.dpreview.com/learn/Image_Techniques/Color_Correction_Speed_01.htm

The author teaches a very easy way to correct white balance.

 

[Tweek]

it works like a charm...thanks!

 

[poseidon]

Some cameras have a special white balance for flash usage...