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"Color Temperature", "Color Balance", "White Balance". People new to photography, digital or traditional, often have a difficult time visualizing what these terms refer to initially. Even those who are familiar with these terms may not have a clear understanding of how they all work together.

This is the second of two lessons on this site focused on color temperature, color balance and white balance. The second lesson, entitled "Using Digital White Balance Outside" examines color balance and lighting outdoors, while this lesson runs through similar techniques for indoor situations.



(Click on any image below for an enlarged view.)

Topics Covered:

  • Defining Color Temperature, Color Balance, White Balance
  • How digital cameras relate to Color Temperature
  • Adjusting the White Balance in a digital camera to various presets
  • Differences between strobe, tungsten, fluorescent lights, and daylight
  • Using light modifiers indoors to control contrast

Equipment Used:
You can click on the blue links below for more info.

 

Color Temperature

In essence, color temperature refers to the frequency of color that can be measured from any particular light source. The efficiency of our own visual experience, however, can make the idea of color temperature somewhat confusing.

This is because our eyes have the intrinsic ability to adjust to color shifts such that a white piece of paper will appear white regardless of what type of light is being cast on it. However, color shifts can be much more apparent in situations where there are two or more light sources of differing color temperatures, like the relatively yellow light that emanates through the windows of a house contrasted against the blue light of dusk.

Color temperature is measured in degrees Kelvin. The most important thing to remember about color temperature is that the higher the Kelvin number, the more blue the light source.

 

The following chart illustrates an approximate color temperature scale (figure 1).



Figure 1

 

Color Balance
Color balance is achieved when a color recording device (like a camera) renders an image close to how the human eye perceives it. White Balance settings, film type, colored filters and gels can all help to assist the device in achieving "accurate" color. Alternately, you can also throw the color balance off to render a different mood or effect to an image.

White Balance
If you shoot with a film camera and want to achieve color balance in a daylight setting, you would use daylight film to match the color temperature of daylight. If you shoot with a film camera indoors with incandescent lighting, you would either choose Tungsten film or place a Tungsten filter over the lens to balance the color temperature. If you are shooting digitally, however, achieving color balance in any lighting situation is just a matter of setting the White Balance (WB) in the camera.

 



Figure 2

In the diagram to the right, you can see how different White Balance settings can affect the color balance of a shot. Remember that if you can match the color temperature of your light source with the correct White Balance setting, you will get color-balanced, or "neutral" results (figure 2).

Click on the image to enlarge if you are having trouble reading the text.

 

To further illustrate how the White Balance function works, we decided to take a series of indoor portrait shots using different color temperature settings. We started by taking a snapshot with a point and shoot digital camera.

Since the built-in flash of any camera (film or digital) is balanced to the color temperature of daylight (roughly 5300 degrees Kelvin), we set the White Balance accordingly. (Most digital cameras have a few White Balance settings that you can adjust manually, as well as an Auto setting.)

 

We activated the flash, set the camera to Program (automatic exposure) and took a shot of our model in front of a sweep of white background paper (figure 3).



Figure 3

 

Although the color temperature is balanced in Figure 3, it also reveals the common problems you get from this type of on-camera flash lighting. Since our light source (the flash) is small and positioned just above the camera, the result is both dimensionally flat and high in contrast. The eyes look darker than they actually are, the reflections in the eyes are unnaturally centered and tiny, and there is a distracting shadow rendered behind the model's head.

To improve the lighting, we decided to light the model with a large, diffused light source for a more natural-looking effect. We also decided to use the Olympus EVOLT E-330 to demonstrate its various White Balance settings. For this next shot, we set up a Large Photoflex Starlite Kit and positioned it to the right of our model at approximately 45-degrees. The Large Starlite Kit uses a 1000-watt Tungsten lamp that's color-balanced to about 3200-degrees Kelvin, about 2100 degrees warmer than daylight or flash.

 



Figure 4

For comparison purposes, however, we decided to use the same WB setting as before (5300K: Daylight). In order to select this White Balance preset, first press and hold down the small WB button at the back of the camera and then turn the Control dial to select the SUN icon (figure 4).

 

Once the lighting was in place, we made a few more adjustments to the camera. Since we wanted the model's eyes to be in sharp focus and for the background to be relatively soft, we set the Exposure and Focus modes to Manual, opened the aperture up to f/4 (the wider the aperture, the more selective the focus), and set the shutter speed to 1/60th of a second to render a good exposure. We then set the ISO to its lowest setting (100), set the Resolution to TIFF, focused and took a shot (figures 5 & 6).

To learn more about adjusting these settings, check out the EVOLT E-330 Basic Startup lesson located on this site.

 

 

The result shows a tremendous difference in the lighting of the shot. The SilverDome soft box from the Starlite Kit had diffused the light to render a soft, wrap-around light on the model's face. The effect is that of a window light. And since the lamp in the Starlite Kit is continuously on, it forces the model's pupils to close down to reveal more color in his irises. Notice the natural-looking catch-light in his eyes as compared to figure 3.

The color of the shot, however, is much warmer than in figure 3 because the camera recorded the relatively warm light from the Starlite (3200K) at a cooler daylight/flash setting (5300K). Remember, the lower the color temperature, the more yellow the light (see charts above).

The closest WB Preset option in the EVOLT E-330 to balance the color temperature of the Starlite Kit (3200K) is the LIGHTBULB (Tungsten) setting, balanced at 3000K. While 200 degrees Kelvin may not seem like a lot, it can noticeably throw off your Color Balance. To get a closer White Balance setting with the EVOLT E-330, you have two options.

 

OPTION 1
If you know the color temperature of your light source, you can select a specific Kelvin number in 100K increments using the CWB (Custom White Balance) option.

To do this, simply press and hold down the WB button on the back of the camera, turn the Control dial to select the CWB option, press and hold the +/- button next to the Shutter button, and spin the Control dial to select a specific color temperature.



Figure 7

Option 2
If you don't know the specific color temperature of your light source, you can still achieve color-balanced results by creating your own White Balance setting. As in most situations, here we decided to use the One Touch WB function to match the color temperature of the Starlite Kit.

To use the One Touch function, first press and hold down the WB button on the back of the camera and use the Control Dial to select the One Touch icon.



Figure 8



Figure 9

Next, point the camera at a white piece of paper or neutral gray card (photo supply stores carry these in various sizes) and fill the frame. Make sure that your exposure settings will allow you to capture a good exposure (one that's not too light or too dark).

Press and hold down the One Touch button on the back of the camera, and then press the shutter button all the way down to record a White Balance setting. If the exposure is good, the screen will prompt you to record the setting. Press OK.



Figure 10

Once we captured a One Touch WB setting, we took another shot (figure 10).

 

In the result, notice how the model's skin tone looks more natural and that the blue in his eyes is truer in color. Remember to use the One Touch WB setting in situations where you don't know the exact color temperature, as it will guarantee you perfect color balance.

To illustrate other Preset WB settings against this Tungsten light source, we first switched the preset to White Fluorescent, measured at 4000K, which is relatively green (figures 11 & 12).

 

When the camera captures light that lacks the green cast, it is stuck with an image that is, in effect, recorded with a magenta filter over its lens. The color wheel to the right illustrates these complementary colors (figure 13).



Figure 13

 

Finally, we took a shot at the SHADE setting (7500K), which would be a good setting to use in the shade of a sunny day. The shade of a sunny day is actually slightly bluer in temperature than that of an overcast day (6500) because the ambient light coming from the sky is blue on a sunny day, rather than gray (relatively neutral) on a cloudy day (figures 14 & 15).

 

 

Notice how warm the shot is now! The White Balance setting is about 4300 degrees cooler than that of the Starlite, making the result extremely warm. And although the color temperature in this image is not rendered "correctly", it does give the shot a different mood. In fact, this image ended up being one of the model's favorites.

As was demonstrated here, it is important to know how to adjust the White Balance of your EVOLT E-330 to render accurate color as well as to create special effects. To see some examples of different WB settings outdoors, check out the lesson on this site entitled "Using Digital White Balance Outdoors".

 

 

White Balance Compensation on the EVOLT E-330
Additionally, the Olympus EVOLT E-330 has a White Balance (WB) Compensation feature to make incremental color shifts from the Auto or Preset White Balance setting. This allows you to create precise color shifts for more artisitic control.

Color shifts, all in seven point increments, are set on two scales. The first scale is R which controls shifts from the red (all + settings) to the blue (all - settings). The second scale is G which controls shifts from the green (all + settings) to the magenta (all - settings).

Setting WB Compensation
To set the WB Compensation from the Main Menu:

  • Press OK to highlight the ISO setting
  • Press the right arrow button once to highlight the WB field
  • Press the right arrow again to highlight the R+/-0 field (this field controls the red-blue shift)
      (Pressing the down arrow from this field will highlight the G+/-0 field which controls the green-magenta shift.)
  • Rotate the Control Dial to the right to shift incrementally to the red (or green in the G field)
  • Rotate the Control Dial to the left to shift incrementally to the blue (or magenta in the M field)

 

 

Check the results of the various settings you make by shooting some images, preferably with some gray tones, to judge the shift in color. A little practice with this feature can help you get results to suit your needs.

 


Equipment Used:
You can click on the blue links below for more info.

Recommended Links

  • To learn more about Photoflex equipment, go to www.photoflex.com
  • For more tips and techniques on lighting and cameras, visit www.webphotoschool.com and sign
    up for access to the Member Lessons.

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