I've now done a lot of simple shoots and two major shoots using the Expo Disc. At first glance, I was very skeptical of this pearlescent piece of plastic in a metal ring but the proof, as my granny used to say, is in the pudding.
Most all, or certainly all the ones I've seen, digital cameras have rich white balance controls. Twenty five years ago, I would use a Minolta Color Meter III for critical film shoots to ensure I was going to get colours that were "correct". With digital, white balance is much simpler to achieve but many folks don't ever switch off auto. That's too bad but a topic for a different post.
What I want to talk about here is building a custom white balance for your shoot. It's really easy.
1. Set your camera exposure properly for the light from the sky, and take a photo of a Kodak 18% grey card. Oops. Don't have one handy, or a grey popup reflector in your bag? That's the point of the Expo Disc.
So here's how it works.
1. Put the Expo Disc on to the end of your lens. You can just hold it there or buy the size that fits the largest diameter filter ring you will typically use.
2. Turn autofocus off
3. Point the camera towards your light source with the disc on (like the sky for example) and take a photo allowing your camera to manage exposure.
4. Go into your camera's menu settings and choose Custom White Balance and select it. It will ask you if you want it to use the current image, meaning that greyish white thing you just shot. Select yes.
5. Now that the white balance has been recordedm, make sure your white balance is set to use Custom. Use this white balance until the end of your shoot or the light changes, such as from cloudy overcast to bright sun.
That's it. While it surely is more work than leaving everything on auto or even picking one of the presets for white balance, you will be getting the right white balance for the light where you are.
Now why bother? Although we can do amazing things in our digital post processing, the closer to a great image we are when we start, the better we are when we end. Having taken the 60 seconds to do this for my cameras prior to shoots, when I load the images into my editor, I have found that my editing time is less, and that I have to do a lot less tweaking. And while I believe that the automatic white balance in my cameras is pretty darn accurate, I have shot the same subject at the same time with custom white balance and with auto white balance and for me, i prefer the custom. Your mileage may vary, but if you want to get a really great white balance, the Expo Disc gets the job done well and with consistency.
Keep making photographs