White Balance and ISO
When shooting in open shade, I often set my white balance to the Shade preset. This adjusts the white balance to maintain a flattering look to the skin. Otherwise, if the white balance is left on the AWB or Sunny preset, the subject will look a tad blue, because the area of shade naturally has a bluish colorcast. By setting my white balance for the Shade preset, a little warmth is added to compensate for that coolness in the quality of light.
I also increase my ISO. It may increase to 200 to 400, depending on the quantity of light and what’s happening with my shutter speed. If I’m using the lens and a wide aperture, such as f/4 or wider, I may only need to increase my ISO to 200 in order to achieve a reasonable shutter speed. However, I won’t hesitate to increase it to ISO 400 or even higher if it means that I can use a reasonable shutter speed in order to ensure sharpness. If I fail to increase the ISO, which I unfortunately do forget to do on occasion, the shutter speed will be too slow and there will be a drop in sharpness. It may not be immediately evident when I’m shooting the images, but it will be painfully obvious when I enlarge the image on my computer screen.
If I move the subject into an area of direct sunlight, I set the white balance to the Daylight preset (Figure 4.3) and I may decrease my ISO to 100 or 200. When we move indoors where the illumination is primarily tungsten light bulbs, I’ll change my white balance to the Tungsten light preset and increase my ISO to at least 800. In each situation, I’m evaluating the light that I have to work with, and adjusting the ISO and the white balance accordingly. From there, I can adjust my aperture, making sure that my shutter speed isn’t too slow. If it is, I’ll open up my aperture and/or increase the ISO.
Figure 4.3 By presetting my white balance for the Daylight preset, I was able to achieve accurate color using late afternoon light when photographing these young girls.
With these considerations made, I’m free to focus on my composition and on building a rapport with my subject.