Basics of Digital Exposure and White Balance

 

Deciding how to light your subject.

It is best to avoid dramatic lighting ratios when shooting digital. A 3 to 1 lighting ratio may result in the color temperature on one side of the face to be noticeably different from the other side. As a general rule, the lower the contrast the better. White umbrellas are better than silver and soft boxes (especially for the main light) produce a better “flat” light than umbrellas.

 

Establishing correct exposure.

Use a flash meter to assure that you have the lighting ratio you want. A good reliable flash meter is the best way to get an accurate exposure. Be willing to move and/or adjust your lights to get an accurate reading. It isn’t any more work to set your lights to exactly f 8 than it is to call f 8.2 “close enough”. A single channel histogram can be very inaccurate as a method of establishing correct exposure. If circumstances require that this be your only method of calculating exposure, your lighting should be very even and the histogram of a gray card, positioned at the subject, should display a single line and should be right in the middle of the histogram grid (center line on Nikons evenly between the two center lines on Canons).

 

Selecting the correct white balance.

Most studio lights produce a light that is between 5500 and 6000 Kelvin. On most cameras this is around the “flash” setting and the “cloudy” setting. The most accurate method of selecting the proper color temperature is to custom set your white balance each time your lighting condition and/or location changes. Methods and instructions vary from camera to camera but use a gray card, not a white card, no matter what the manual says. The exposure must be accurate before you can get an accurate white balance. Use the same instructions for positioning the gray card as above and set your white balance to the card.

 

Other settings and information

With a modest lighting ratio, correct exposure and correct white balance all other settings on your camera should be fine at their default settings. Most newer digital cameras adjust contrast, saturation, hue and sharpening automatically. This is usually called something like Dynamic Image Optimization or Picture Style Mode. In many cameras the default setting is called Normal which is really Auto. We have seen much better results, switching this to Custom and setting each independent control to normal. Because all cameras handle this differently, please call if you need help with this. Color Space should always be set to sRGB.

 

The most common mistakes.

• Auto exposure modes will not work with Studio Lights.

• ISO on flash meter does not match ISO on Camera.

• Auto White Balance absolutely does not work.

• Changing an image processing value like saturation or contrast and forgetting to change it back.

• Under exposed is better than over exposed but right on is better than two stops under.