How to Set a Custom White Balance with the ExpoDisc:
Cover the Lens. Attach the ExpoDisc to the front of your lens (white side towards camera). If your ExpoDisc is larger than your lens filter size, simply hold the ExpoDisc flat over the lens.
Manual Lens Focus (If Necessary). Some cameras require the lens to be in manual focus to capture an exposure through the ExpoDisc. Note: This is not necessary when using Nikon cameras to set a Preset white balance.
Set Camera Exposure. Program or Aperture mode will automatically produce a good exposure through the ExpoDisc when shooting in ambient light. However, if you are shooting in Manual mode you must first set a good exposure prior to capturing your custom white balance reference image.
When Using Flash. You must set your custom white balance using the same shutter speed that you intend to use when photographing your subject. Your flash must fire when setting the custom white balance.
Aim the Camera (Measure Incident Light). With your exposure set and the ExpoDisc covering the lens, aim the camera from your subject’s position back towards your intended shooting position (as if you were using the camera like an incident light meter). From this position press the shutter release button to capture the 18% reference image that you will use to set your custom white balance.
Set the Custom White Balance. Follow your camera’s instructions to select the ExpoDisc's 18% reference image to set your custom white balance.
Finished. Remove the ExpoDisc, and if necessary return the lens to autofocus.
Set a new custom white balance when the light changes.
Note, when using flash you must set our custom white balance using the same shutter speed that you will use to photograph your subject.
ExpoDisc White Balance Tips:
Measure the Incident Light. Understanding that the ExpoDisc is an incident metering tool will help you to use it properly in a variety of shooting situations, including in-studio, outdoor, ambient light, and in certain on-camera flash applications.
Ambient Light (Indoor or Outdoor). Aim the ExpoDisc towards the brightest light source, or area of the sky. It is best to stand in the same light as your subject to set the custom white balance. Note: Direct sunlight poses no risk to the camera’s optics because the ExpoDisc diffuses and passes only 18% of the light through to the camera’s sensor.
Off-Camera Flash. Point the camera towards the main light (key light) to set your custom white balance.
On-Camera Flash (Bounce Flash). Aim the camera and the flash towards the bounce surface (e.g., ceiling) to set your custom white balance.
On-Camera Flash (Direct Flash). We do not recommend setting a custom white balance with the ExpoDisc when directly lighting subjects with on-camera flash. Doing so may create an undesirable colorcast by incorporating back-lighting or side-lighting.
ExpoDisc 2.0 Portrait Warming Filters (optional):
Portrait Warming Filters (gels) attach to the front of the ExpoDisc 2.0 to create warmer images for pleasing skin tones.
ExpoDisc 2.0 includes two levels of custom Warming Filters (gels) which can be inserted into slots on the face of the ExpoDisc. Under daylight balanced studio lights, the +1 and +2 custom warming filters provide 300° and 500° Kelvin warming, respectively.
- ExpoDisc 2.0 Neutral 5900 Kelvin +6 tint
- ExpoDisc 2.0 w/ +1 Warming Filter +300 Kelvin (from 5900 to 6200) +7 tint
- ExpoDisc 2.0 w/ +2 Warming Filter +500 Kelvin (from 5900 to 6400) +7 tint
To use a Portrait Warming Filter, attach the filter to the front of the ExpoDisc (prismatic lens side). The two filter tabs should be placed into small grooves located on the rim of the ExpoDisc.
Note: Your ExpoDisc will not correctly meter 18% incident exposure with the Portrait Warming Filters attached.
Metering for 18% Incident Exposure with ExpoDisc:
To Expose for Evenly Lit Subjects (soft highlights and shadows)
- Attach the ExpoDisc to your camera lens
- Put your camera in Manual exposure mode
- Stand at subject position, then point the camera toward your intended shooting position to measure the incident light illuminating your subject (Note the camera meter as seen through the view finder)
- Adjust aperture, shutter speed, or ISO settings until camera meter indicates a proper exposure
- Take one test shot through the ExpoDisc
- Check the histogram of the test shot. A correct exposure should yield a gray image with a centered spike
- Remove the ExpoDisc to photograph your subject
To expose for highlight detail, follow the steps above then decrease your exposure 1 f/stop.
To expose for shadow detail, follow the steps above then increase your exposure 1 f/stop.
Dust Mapping the Camera Sensor with ExpoDisc:
To check your camera sensor for dust, or to create a dust map for use in image editing software.
- Attach the ExpoDisc to your camera lens
- Place the camera in Aperture exposure mode
- Set the camera aperture to f/16
- Set the lens zoom to 50mm or higher
- Place the lens in manual focus mode
- Aim the camera towards the brightest available light source
- Click the shutter to capture a gray image through the ExpoDisc
- Evaluate the resulting gray image to identify dust spots on the camera sensor
Now you are ready to clean your sensor, or to use the gray frame image to create a dust map in your image editing software.