Flash WB - What Kelvin Rating?

[jamesward93]

Wonder if anyone can help me out here. I am using a Canon 1ds Mk3 and after looking at a few shots taken in a studio last week, i noticed all of my images seemed a bit warm (orange). I was using bowens flash heads and had the cameras WB set to flash. I always thought that flash WB was around 5500k, but when i check the images in lightroom, the 'as shot' WB is 6100k, hence why i am getting warm looking images.

Can anyone shed any light on this?

 

[Canon Bob]

James,

I'm far from being an expert on these things and rarely use flash except for macro shots. What I can say though is that the specified temperture on a flash is usually at full power....Canon Speedlites are specified as being 5500k but are more like 6200k in reality. If you reduce the power then the temperature increases (to around 6900k at the lowest power settings). To get the actual lighting temperature of the scene being shot you would also have to factor in the other light sources around and their percentage contribution to the overall illumination of the subject.
A tricky assessment to make but studio lighting is likely to reduce the temperature somewhat and your 6100k is probably not too far away if you had some tungsten lamps in the recipe.

Bob

 

[HoppyUK]

Canon cameras do adjust for flash colour balance according to output. I don't know how, or by how much, or what happens when you use studio flash. I use both Canon guns and Elinchrom studio units with my 40D and have never noticed anything but good colour balance, which tends to make me think that maybe the colour shift is not camera related?

As Bob says, if you've got tungsten modelling lamps in there, perhaps turned up high and with relatively low flash power, then even with a short exposure time you'll get a tiny bit of orange in there. If you use a longer shutter speed, then you'll definately get an orange cast. Number one suspect methinks. Also think about reflections from coloured walls etc, not to mention possible contamination from the flash reflectors and brollies.

The other thing is that higher colour temperature is more blue, not orange/red, but are you saying that the camera has logged this and has overcompensated?

If the problem persists, can't you just dial in the colour temperature manually, and adjust it for whatever colour tone you like? Or shoot Raw and adjust in post?