- Use a grey card. These have been used for years as a quick, cheap and cheerful way to set your white balance accurately. Simply place the grey card in the light where your subject is and take a photo, filling the frame with the grey card. You can then use this to set your white balance using the "custom" setting. (see this post on how to use your grey card for more information) You can get large cards like this 8 inch x 10 inch Gray Card which are easier for your subject to hold, or Pocket-Sized Grey Cards that will easily fit into your camera bag. Grey cards can also help you set exposure.
- Use an ExpoDisc . This is so on my "want" list! It does the same job as a grey card, only better, and it also makes the whole process of setting your white balance easier. Instead of having to have someone hold up a grey card, you can simply hold the Expodisc over your lens and take a picture, making sure the lens is completely covered and you are pointing the camera where you are taking the shot. You then set your custom white balance in your camera settings (same as the grey card) and you should have perfect white balance. If you are buying one, make sure you buy a size that is big enough to cover your largest lens - I would recommend getting the 77mm as it will be "future proof" should you get a larger lens at a later date.
- Use a Neutral or White Element Don't have an Exposdisc or Grey Card to hand? you can use something in the scene that you are photographing that is neutral or white to set the white balance. It won't be as accurate as a grey card or an expodisc but will get you reasonably close. This could be a white piece of paper, white socks, a grey sidewalk, or even the white lid of a coffee cup. You set white balance in the same way as using a grey card, by photographing and custom setting the white balance.
(Image from Frost Electric)
Update: A reader also advised of this method: (thanks Brianna!)
- Use a White Balance Lens Cap Essentially this does the same job as a grey card (and the expos disc) in that you use this to set a custom white balance. As this acts just like a lens cap, you should have this with you at all times, and can be easier to than having to take a grey card with you, and is a fraction of the price of the Expodisc!
If all else fails you can always change the white balance later in editing, but it can be a pain to get right later. Use one of these to set your white balance in camera and you're done!