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White Balance help – floodlights
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I’ll be taking my camera along to an outdoor go karting track tonight, which is floodlit. They’ve no probs with my taking pics trackside (incl flash), but can’t confirm what kind of lighting they use, except for “it’s the kind that comes on slowly”. Could this be sodium?
Anyone know what type it most likely would be, more to the point, what is the best WB setting to use? Or what colour temp to set?
Let’s just hope it doesn’t pee down like over the past few days & nights!
Cheers.
What camera are you using?
Personally (if you can) I’d shoot in raw and sort out WB later. Either that or if your camera has a custom white balance option then use it – photograph something white (or grey depending on the camera) at the location, and tell your camera to set WB to that picture. If you don’t know how to do that, either ask on here, or try looking in the manual for your camera. Difficult to give any more detailed advice without knowing the camera make / model. There’s a field you can fill in on your profile to detail this, to save having to specify it in posts, if you didn’t know already.
Hope it helps!
Tim
Thanks Tim, maybe that’s a good incentive to fill in that field!
I’m using a Canon 20D and will read up on setting custom WB. I’ll have my grey/white card with me so that’s probably the way to go. I’ve recently started shooting RAW – and much prefer it tbh – so that’s not a problem for me, and my backup was basically to shoot AWB & clean up later. Naturally it’s nice to get a clean image to begin with plus it all helps in the learning curve (see my avatar!)
The fool proof way of getting correct white balance that I use in very tricky situations is to buy an 18% grey card (Jessops have them), take a photo of it under the lighting, using raw all the time. When you get to converting the files then you can (depending on the RAW convertor) open up the image and click somewhere on the grey card and set the white balance for this point, you can save that WB and apply it to all the rest of the RAW files automatically. I’m sure you can do this with ACR for Photoshop and Elements but cant remember exactly how, I use Nikon’s Capture 4.4 and Capture NX.
You can also get a widget called an ‘expodisk’ that you fit over the lens that does something similar but you just use the WB value for the first photo taken with the expodisk on.
If you can find yourself a lid from a tube of pringles (the frosted opaque plastic lid, not the clear one) you can use that as above and apparently it works almost as well!
Above all, use RAW!
The fact that you describe it as one of those light sources that “comes on slowly” indicates that it’s a gaseous light source. It’s probably going to be either Mercury Vapour, Sodium Vapour, Metal Halide, or High Pressure Sodium, although the latter are rarely used these days. Regardless, whichever it is, you’re screwed! The best you can hope for is a compromise. None of the gaseous light sources are continuous spectrum light sources – instead they produce a series of monochromtic spikes of energy within the spectrum of visible light. This is what has always made them difficult to filter for in the past and they will continue to cause grief with digital cameras white balance settings.
My suggestion would be to shoot raw and take along a grey card and shoot that as your first frame and every half hour or so after that if your there before it get’s fully dark. You can then use this as your white balance reference point in your RAW converter and apply that to the other shots within a given time frame. Of course, if it’s pitch black when you start out you probably only need to take the one shot and can apply the white balance setting from that frame to all the other frames.
The other option is to just shoot flash. You can still let the ambient light show in your exposures, but provided the flash provides the majority of the exposure on your principal subject, then letting the background do what it wants to in terms of WB is OK.
I’ve heard of the expodisc and might invest in one soon though a Pringles lid looks like a good backup – good tip!
Oh, the guy just got back to me, said that they use Philips SonT 400W bulbs. A quick google shows that these are high pressure sodium lamps.
Looks like it’ll be a night of experimentation then (as usual!). It’ll be dark by the time the event starts (7.30pm).
WB and 18% grey???
A grey card is for exposure not white balance. A white card should be used for setting custom white balance.
The job of setting the WB in your situation is bad enough without you having to sort out a custom WB taken from a grey card.
:cry:
Valentia wrote:
WB and 18% grey???
A grey card is for exposure not white balance. A white card should be used for setting custom white balance.
The job of setting the WB in your situation is bad enough without you having to sort out a custom WB taken from a grey card.
:cry:
Yes I’ll be using the white card (which is on the back of the grey card).
As regards exposure I have no idea what the ambient light situation will be, and how much I will be forced to use flash (for example at pitstops/driver changes).
Just out of curiosity, I had a look at the Philips website to see if they had a graph of the spectral output of this bulb – sure enough they do, and an interesting one it is too.
I would imagine the easiest way to correct for this is in photoshop with LAB curves adjustment layer.
Valentia wrote:
A grey card is for exposure not white balance.
Says who?
In fact it rather depends on how you do the custom white balance. A white card is not necessarily always the best solution. I use a WhiBal for custom white balance and that uses a calibrated grey card (not a Kodak 18% grey card) for optimum results.
And from the Canon EOS 20D manual “Instead of a white object, an 18% gray card (commercially available) can produce a more accurate white balance.”
Thorsten wrote:
Valentia wrote:
A grey card is for exposure not white balance.
Says who?
In fact it rather depends on how you do the custom white balance. A white card is not necessarily always the best solution. I use a WhiBal for custom white balance and that uses a calibrated grey card (not a Kodak 18% grey card) for optimum results.
Says me. I’m talking about, as the original poster is, taking the WB with the camera. I don’t know what the WhiBal has to do with this thread?
Valentia wrote:
I don’t know what the WhiBal has to do with this thread?
It has to do with setting White Balance (and the additional fact that one sets it using a grey portion of the WhiBal). And that, as has already been sugested, the OP adjusts the WB in RAW processing after the shoot rather than setting a WB for the shoot itself. When shooting RAW, the WB setting doesn’t really matter, although it’s probably advisable to use a pre-defined WB setting rather than AWB.
Obviously the WhiBal uses a proprietary method of getting WB. Fine if that’s what you are using but confusing the issue when a person is just using their camera’s WB function.
WhiBal is simply a calibrated grey card – I wouldn’t consider that proprietary. I apologise if I caused confusion by referring to it rather than a regular 18% Grey Card in conjunction with Canon’s stated advice that a grey card can produce more accurate custom white balance results (page 52 of the EOS 20D manual). I’ll refrain from making any further posts on this as I have no desire to inflame matters.
I should have known better….. Thorsten :) I mean that in the nicest possible way.
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