An ExpoDisc is a professional white balance filter. If you remember our white balance comparison guide, auto white balance was not always the best option. Especially in tricky lighting situations with mixed types of light, the preset settings also are not ideal for capturing great WB straight out of the camera. The ExpoDisc is a tool that works with your cameras custom white balance function. "Whether you’re shooting RAW or JPEG, simply read and set white balance with the ExpoDisc before shooting and you’ll reduce or eliminate the need for post-capture color adjustments. Why spend time fixing color if you don’t have to?"
Exterior (natural light + bounce flash)
Left: using auto white balance, Right: custom WB with ExpoDisc