ExpoDisc 2.0 FAQ
1. Does the ExpoDisc work with digital video cameras?
Yes. White balance principles are the same for both digital video and digital SLR cameras. The ExpoDisc can be used with any digital camera that has the capability to set a custom white balance. This includes digital SLR's, point and shoot, and prosumer fixed lens cameras.
2. Can I use the ExpoDisc to set a custom white balance if the camera manufacturer recommends use of a gray card or white card?
Yes. The ExpoDisc can be used to set an in-camera white balance, or it can be used to capture a reference image for post production color adjustments.
Most photographers discover that white balance targets like gray cards and white cards are inconvenient and awkward to use because they must be positioned precisely while avoiding shadows and reflections.
Small white balance targets are portable, but their small size also makes them difficult to use for in-camera white balance. This often restricts their use to more time consuming post production color correction.
Large white balance targets are simply too big to carry with you all the time.
Keep in mind that printed gray cards and white cards must be replaced often because the inks and dyes used in their production change color when exposed to air and light.
3. What makes the ExpoDisc the best white balance tool?
- Small and lightweight so it's easy to take with you. This means you will have it when you need it.
- No special software and no post processing is required to use the ExpoDisc.
- You only need 10-15 seconds to set an accurate custom white balance with the ExpoDisc.
- Each ExpoDisc is calibrated by hand in our California facility.
- The ExpoDisc is calibrated for color neutrality and an 18% light transmission on a transmission spectrophotometer.
- An ExpoDisc gray frame reference image can be used to batch process RAW images.
- The ExpoDisc can be used to meter an 18% incident exposure.
- The ExpoDisc can be used to check sensor for dust, and to create a dust map.
4. How does the ExpoDisc work as a white balance filter?
The ExpoDisc transmits 18% of light in the visible spectrum through to your camera’s image sensor. The resulting featureless image, or 'gray frame' captured through the ExpoDisc represents the average color temperature of light at the moment of capture. Your digital camera compensates for, and neutralizes the color of light represented in the 'gray frame', resulting in good color balance for that particular light source.
5. How do I know which size ExpoDisc to buy? Do I need an ExpoDisc for each lens?
The ExpoDisc 2.0 is available in 77mm and 82mm filter sizes. The filter size of your lens can typically be found on your lens barrel or inside your lens cap written in the following way: ø77mm, ø58mm, etc…
A larger ExpoDisc can be used with smaller filter size lenses by simply holding the ExpoDisc over the lens during the white balance procedure.
Note, some smaller lenses may benefit from the use of a step up ring. Specifically we have heard feedback from customers that when using an 82mm ExpoDisc over some 72mm lenses, the filter and lens rings do not line up well. In this case a step up ring should resolve the problem.
When using a lens larger than 82mm, the only work around is to set your custom white balance with a smaller lens and then swap over to your 95mm lens.
6. Can the ExpoDisc be used in conjunction with other filters?
Yes. The ExpoDisc can be used in conjunction with most other filters such as polarizing, skylight, ultraviolet, and color balancing filters.
Care should be taken when changing lenses and filters. A color cast can be introduced if a lens filter is attached, or removed from the lens after the white balance has been set.
When using a polarizing filter, you can simply leave it on your lens during the custom white balance with the ExpoDisc.
If you’re using a colored filter, like the yellow #8, then you would want to remove the colored filter when setting the custom white balance to achieve a neutral white balance and then add the yellow #8 back to your lens to create the color effect you are looking to achieve.
7. Do I leave the ExpoDisc on when taking a photograph?
No. The ExpoDisc is only on the lens while performing your camera's white balance or exposure metering procedure. Remove the ExpoDisc after the procedure.
8. Do I need to set a new white balance after switching lenses?
No. Most modern lenses are optically clear and will not add any color cast that would affect the white balance if interchanged on the camera. However care should be taken to note if there are any filters on the lenses you are using.
9. What is the difference between the new ExpoDisc 2.0 and older ExpoDisc models?
We have improved our manufacturing and calibration processes over time. ExpoDisc 2.0 represents the highest quality white balance tool that ExpoImaging has ever offered.
ExpoDisc 2.0 improvements:
- Securely attaches to similarly sized filters and lenses with a push button spring mount design.
- Molded from durable polycarbonate materials that can withstand drops, and will not scratch your other camera equipment.
10. Will the ExpoDisc work with my digital camera?
The ExpoDisc works with all major camera brands, including: Canon, Nikon, Sony, Panasonic, Pentax, Olympus, Samsung, Lumix, and Leica. It can be used with any digital camera equipped with a custom white balance capability, including all digital SLRs and most point & shoot cameras.
11. What kind of warranty comes with the ExpoDisc?
All ExpoImaging products come with a limited warranty to be free of defects in workmanship and materials for a period one (1) year from the date of original retail purchase. If the product proves defective within the warranty period, then it be will replaced.
12. What camera white balance setting do I use when setting a custom white balance?
Nikon cameras instruct the user to place the camera in the PRE white balance setting prior to capturing an in-camera custom white balance "reading".
For most other camera brands, if your custom white balance procedure requires selecting a captured image, i.e. Canon, then we recommend using the designated custom WB setting.
13. My Nikon camera displays the "no good" error message when I set a Preset white balance. What am I doing wrong?
Nikon cameras may produce a "no good" error message during the Preset white balance procedure if the exposure is incorrect (over or under exposed), or if the color temperature of light is out of range of the camera's ability to correct, e.g. campfire light is too warm (yellow).
Generally, most Nikon "no good" white balance errors can be fixed by correcting the exposure during the white balance capture. If shooting in ambient light, set the camera to Aperture Priority and try the Preset white balance procedure again.
14. When I change my camera exposure do I need to set a new custom white balance?
No, if you are photographing in unchanging (constant) ambient light, then you do not need to reset your white balance when you change your exposure.
Yes, if you are using electronic flash, then we recommend resetting the white balance when you change your exposure.
Why? When shooting with electronic flash changes in the shutter speed alter the ratio of ambient light to flash, particularly at shutter speeds slower than 1/125 of a second. For consistent white balance results it is therefore important to photograph your subject with the same exposure (shutter speed) that you set your white balance.
15. Should I save the custom white balance reference image "gray frame"?
If your camera requires selecting a captured image to set an in-camera custom white balance, e.g. Canon, then you only need to select the ExpoDisc reference image in the custom white balance procedure to import the relevant data into your camera's memory. Your camera will save this information until you replace it with a new custom white balance reference.
Once the white balance procedure has been completed, you may change memory cards, or delete the reference photo without losing your custom white balance settings.
If you wish to color balance your images later in photo editing software, then you should save the custom white balance reference image. These reference images may also be useful as markers to indicate changes in lighting if you are post processing your images.
16. How do I use the ExpoDisc with flash?
Off-Camera Flash. Set your custom white balance from the subject position while aiming the camera back towards your main (key) light.
On-Camera Bounce Flash. Aim the camera and flash towards the bounce surface to set your custom white balance. This technique will correct for any changes introduced by the color of the bounce surface itself, e.g. a yellow ceiling or wall.
On-Camera Direct Flash. We do not recommend setting a custom white balance with the ExpoDisc when directly lighting subjects with on-camera flash. The ExpoDisc is an incident light metering tool and requires your ability to aim it directly at the main (key) light source.
17. My pictures have a colorcast after setting a custom white balance. What did I do wrong?
The same color of light that is falling on your subject needs to pass through the ExpoDisc during the custom white balance measurement.
Pictures with a warm colorcast usually result from improperly aiming the camera towards a cooler light source then what is actually illuminating the subject. And vice versa, if your images turns out to have a blue cast when using the ExpoDisc, then it is likely the result of aiming it toward a light source that is warmer than what it actually falling on the subject.
Examples of cool lights include blue sky, electronic flash, shadow / shade, and daylight.
Examples of warm lights include tungsten, halogen, fluorescent, or early morning, and late afternoon sunlight when the sun is low on the horizon.
You need to go to your subjects position and aim the ExpoDisc toward the dominant light that is falling on your subject.
18. How do I set a white balance in mixed lighting?
Digital cameras can only balance to one color temperature of light at a time. In a mixed color temperature shooting environment, we recommend identifying and white balancing your camera towards the predominant light source illuminating your subject.
- If the different sources of illumination on your subject are relatively equal in color and intensity, then stand near the subject and white balance your camera while aiming the camera back towards where you will be positioned when taking the picture.
- In a mixed light environment with warm and cool lights, overall warmer (yellow) image tones will result when the camera is white balanced while aiming towards cooler (white or blue) sources of illumination, e.g. electronic flash, north facing window, blue sky, etc.
- In a mixed light environment with warm and cool lights, overall cooler (blue) image tones will result when the camera is white balanced while aiming towards warmer (yellow) sources of illumination, e.g. tungsten, halogen, late afternoon sun, etc.
- We recommend white balancing towards the cooler illumination in a mixed light environment. For example, photographing under a combination of tungsten and daylight illumination looks best when the camera is white balanced towards the cooler daylight. This is because the correction necessary to color balance the bluish daylight results in warm image tones in those areas illuminated by the already warm tungsten light.
19. Can I use the ExpoDisc to white balance stadium and gym lights?
The ExpoDisc can be reliably used to white balance metal halide lamps, like those commonly used in professional sports stadiums and gyms. Team photographers for professional football, hockey, baseball and basketball have used the ExpoDisc to white balance their cameras for many years.
However, white balancing your camera in the presence of Sodium or Mercury vapor lights is unpredictable because these lights have a discontinuous color spectrum (i.e. they do not contain all the red, green and blue primary colors). Your camera may not be able to compensate for all of the missing color in your source light. Furthermore, the continuous on and off cycling of these lights creates additional challenges because their color temperature fluctuates as they cycle.
20. Why do I need to switch my lens focus when using the ExpoDisc?
When attached to your camera lens the ExpoDisc presents a featureless, out-of-focus image to the camera (most cameras will prevent the shutter from being tripped in auto-focus mode if the camera cannot focus on a subject). Setting the lens focus to manual therefore allows an out-of-focus image to be captured for the white balance procedure. Return the lens to auto-focus mode after setting the white balance.
Note, Nikon camera users do not need to switch their lens focus to manual if they are using the in-camera Preset white balance procedure because the camera's auto focus function is disabled when PRE is blinking in the LCD panel.
21. How do I set the white balance when shooting a landscape?
When using the ExpoDisc to set your custom white balance, you want the same color of light that is falling on your subject to pass through the ExpoDisc during the custom white balance procedure. Where you will aim the ExpoDisc depends on the given shooting situation.
In landscape photography, the best white balance results are obtained by aiming the ExpoDisc towards the sky when photographing under cloudy skies, open shade and deep shade. Under direct sunlight, aim the ExpoDisc so that it captures the sunlight. Note, direct sunlight poses no risk to the camera’s optics because the ExpoDisc diffuses and passes only 18% of the light through the camera’s sensor.
22. How do I set the white balance when the subject has his/her back to the sun or is backlit?
Use the ExpoDisc like an incident light meter. The best results are obtained by standing near your subject and pointing the camera, with the ExpoDisc on the lens, back to where the camera will be positioned when you take a picture. By utilizing this method you will balance your camera to the color of light that is illuminating the front of the subject, not the backlight. This method also works well when the subject is in shade or near a brightly colored, reflective surface.
23. Can the ExpoDisc be used for underwater photography?
Use of the ExpoDisc underwater is not recommended. The properties of light underwater are significantly different than light in the Earth's atmosphere. Major factors influencing light underwater are: the attenuation of light as depth increases; the scattering of light from suspended particles; and, most importantly, reduced color saturation. At a depth of just 20 feet (6 meters) almost all red light has been filtered out by the water. Without special lights, underwater photography using natural light is only possible in very clear water at shallow depths of just a few feet. The ExpoDisc was not designed to address these issues.
CAUTION: The dyes in the special filters used to manufacture the ExpoDisc could be affected by immersion in water or other liquids. Salt water, in particular, is very caustic and could severely damage the ExpoDisc. The ExpoDisc Limited Warranty is void if the filter has been immersed in liquids.
24. What are the temperature shift values of the ExpoDisc 2.0 +1 and +2 Portrait Warming Filters?
ExpoDisc 2.0 Neutral: 5900 Kelvin +6 tint
ExpoDisc 2.0 w/ +1 Warming Filter: 6200 Kelvin +7 tint
ExpoDisc 2.0 w/ +2 Warming Filter: 6400 Kelvin +7 tint
ExpoDisc v1 Portrait Filter: 6450 Kelvin +8 tint
