ExpoImaging makes a smart little product that you’ve probably heard mentioned before (it’s been on the market for a few years now)—ExpoDisc. Perhaps you were curious about it but didn’t bother investing in it because you have a reliable gray card you use every time for setting your white balance.
The ExpoDisc is a tool to enable photographers to quickly and easily customize their white balance setting by fitting the disc to their lens and measuring the incident light passing through the ExpoDisc to custom set their white balance.
It’s the determination of the exact color adjustment necessary for a digital camera to render a pure white object so that it appears pure white in the captured image.
If you’re like me, often I just leave my camera’s settings on auto white balance and then adjust the white balance during post-processing in Lightroom. However, by taking a custom white balance reading before each particular lighting situation, I’ll save myself lots of time guessing at the proper white balance for my subject, especially for portraits.
How Does the ExpoDisc Work?
Either snap the ExpoDisc over the front of your lens, or if using a larger diameter ExpoDisc than your lens size, hold the Disc in place.
Prepare your exposure for the shot. Aim the camera so the same light that will be illuminating your subject passes through the ExpoDisc. Tip: Stand where your subject is and point the camera back to the location where you will be shooting from.
When using strobes, point the camera towards the main light source. Set your camera’s exposure first for your shoot, and fire the strobes when you take the custom white balance reading.
Capture the incident light while setting your camera’s custom white balance (refer to your camera manual on how to do this).
Rather than using a gray card, white card or your white sock (um, actually that wouldn’t work anyway), to set white balance, setting the white balance manually using an incident filter instead should be much more accurate.
A situation where the ExpoDisc would have come in handy: I was shooting a presentation/runway event at the Scandinavia House for Fashion Week, NYC. There were really hot lights set up at the end where the photographers and videographers were stationed, and the backdrop for the models walking down the makeshift runway was glass windows with reflection from the lights. Not ideal. I guessed at a custom white balance setting—around 5500K—but had to do additional adjusting of the white balance setting during post processing. Had I used the ExpoDisc, I probably would have been able to more accurately set the white balance by measuring the incident light through the disc.
The ExpoDisc comes in 2 variations: ExpoDisc Neutral and ExpoDisc Portrait (warm), and in a variety of lens filter sizes. It’s probably best to get a 77mm ExpoDisc or larger. While you can snap this onto the front of your 24-70mm lens, you could also just hold it up in front of your smaller lenses and take a light reading.
Accurately set your camera's white balance manually for each type of photography situation, and eliminate time during post-processing.
While lightweight, it's another item to carry in your camera bag.