I’m not always getting good flash exposures with my Nikon D5100 and SB-800 Speedlight. Sometimes the photos are too bright, and, in other cases, they are underexposed. Any suggestions?
This is a common question from my students who own other brands of cameras. Randy, you’re using very sophisticated, high-tech equipment with “intelligent” Matrix metering and i-TTL flash metering, so you should be getting excellent flash exposures in many situations. Of course, that assumes that all camera and flash features are at the appropriate settings. For example, make sure that the SB-800 AF Speedlight is set for i-TTL mode and that you have not inadvertently set some Flash Exposure Compensation. Also, check to ensure that the metering pattern on the camera is set to Matrix for the greatest reliability (not Center Weighted or Spot).
Hint: With subjects that are extremely close to the camera—or very far from your position—be sure to check the flash range data on the LCD panel on the back of the flash unit. As you change the ISO level on the camera, the data will also change, indicating the effective flash range at different ISOs.
Using bounce flash or a diffuser—whether the built-in wide flash adapter panel or a light-modifier accessory such as one of the very useful Gary Fong products—will reduce the effective flash range. And if you use the FP High Speed Sync mode, the flash range will be very short. In such situations—or with a distant subject in low light—set a higher ISO level (to make the sensor more sensitive to light) or move closer to the subject. When the subject is unusually close to the camera, however, set the lowest ISO level and also flip the built-in diffuser down over the flash head.
One of the benefits of digital photography is that you can snap a test photo and check the results instantly to see if you need to make any adjustments. The “correct” exposure, especially for fill-flash photos, is often a matter of personal judgment. If you don’t like the results you’re getting at default settings, start experimenting with Flash Exposure Compensation. For a more gentle effect outdoors, try setting a -2/3 level on the flash unit (not on the camera). With very light-toned or highly reflective subjects, however, you may need to set a +1 (or similar) Flash Exposure Compensation level to prevent underexposure.
Practice with basic flash photography at first, but study your owner’s manual or books such as David Busch’s Nikon D5100 Guide and the Nikon Creative Lighting System Digital Field Guide. Similar guides are available for other brands of equipment too. Learn more about the advanced flash options available with your equipment, and begin experimenting with those features and techniques. While getting good flash exposures should not be difficult, you will also be able to achieve some pro-calibre lighting effects—using wireless off-camera flash, for example—after developing a bit of expertise.