White Balance and Sodium Lighting

[dubnut71]

You guys have bags more experience at this than me so I will try you for some help!:o

I take quite a few pics under Sodium lighting in gym's or large halls (Photos of Kickboxing mainly when I am fighting or some of the team)

I am using a Sony DSC-P200 and get very blurred or discoloured results (like the white balance is out)

I have just worked out at home that in P or M mode I can change the WB for incandesant or flourescent light but this doesn't work for sodiumsI have found. I have also had a play by setting the WB by going to WB set and taking a pic of the back of the instruction manual (white!):o :o to set the WB , is this acceptable? When I do this with flash selected it seems to "catch" the conditions in my room just now OK but will the same technique work when I try it at the weekend?

Or is it something else thatn the WB thats off?

I have only the basic understanding of depth of field and exposure and am only just beginning to fiddle with the cam off its "point and shoot settings"!!!

Thanks in advance (ps and DSC-P200 users out there?)

Graeme

[parish]

Setting the WB manually as you describe should work, although I've never actually tried it with mine (Canon Powershot A70).

One way to fix the pics afterwards is to equalize them in Photoshop or similar.

This was taken on the Megs stand at the Classic Car Show. The lighting was mercury vapour which is a bright white light yet the pics still come out as though they've been taken under sodium lighting. The second pic is how it looks after equalizing it - it's not perfect but is a whole lot better. I'm not a PS expert but I bet it would be possible to improve it even more, but I'm not sure what to change :confused:

951

952

[Brazo]

FWIW white balance isn't white its 18% grey

[dubnut71]

Setting the WB manually as you describe should work, although I've never actually tried it with mine (Canon Powershot A70).

One way to fix the pics afterwards is to equalize them in Photoshop or similar.

This was taken on the Megs stand at the Classic Car Show. The lighting was mercury vapour which is a bright white light yet the pics still come out as though they've been taken under sodium lighting. The second pic is how it looks after equalizing it - it's not perfect but is a whole lot better. I'm not a PS expert but I bet it would be possible to improve it even more, but I'm not sure what to change :confused:

951

952

Cheers Parish,

Although I cant see the pics attached I am sure there would be a PS "fix" in there for me too. I am not currently a PS user I use photoimpact and PS mayhave to wait for my next PC upgrade as this one may just fall over if I add anything else!

My pics were blurred as well, I am going to experiment with flash and either burst mode on the cam or force the shutter speed down?

GC

[dubnut71]

OK, can see them now, wow what a difference!

Brazo - I bow to your knowledge!!

[parish]

I am not currently a PS user I use photoimpact
Which version? I've just had a look at the website and the current version at least has a WB setting which you can use to correct colours. Judging by the complexity of the program I imagine that if your version doesn't have this feature it will be able to equalize the image - look under Image, Levels, Colour Balance, or something like that.

[dubnut71]

Cheers Parish will do!

[nzgunnie]

Sodium is particulary hard to balance for, since it is different from most artificial light sources. It actually contains only one wavelength of light, orange!

Most light sources use a reasonably wide part of the spectrum, albeit skewed away from daylight, but not Sodium. In the old days of film there was no easy solution, as the standard balancing filters wouldn't work, and unfortunately in the days of digital things have not improved much.

Although you should be able to reduce the strong orange look, a sickly yellow will most likely still be present.

[parish]

Thanks for that tip nzgunnie. I guess that is why sodium streetlights distort car colours so much?

Also, why do mercury vapour lights cause such a heavy orange/yellow cast - see pic of the P1800 above? I guess it's because, although they appear bright white to the human eye, the colour temperature is quite a long way off daylight?

[nzgunnie]

Most artificial lights will look white to the eye, fluro lights do, but take a photo under them and you will se that they are quite green.

I remember learning that it is psychological, they eyes expect a light source to be white, and unless there is a comparison available, the brain will quite happily do it's own whitbalance and make the light source 'look' white.

I can't remember all the different colour temperatures off the top of my head, but the colour of a light is measured in degrees Kelvin, with noon daylight being around 5500k.