Nikon D7000 manual High-Speed FP Sync

Chapter 12 ■ Making Light Work for You 417

I generally end up with sync speed problems only when shooting in the studio, using studio flash units rather than my D7000’s built-in flash or a Nikon dedicated Speedlight. That’s because if you’re using either type of “smart” flash, the camera knows that a strobe is attached, and remedies any unintentional goof in shutter speed settings. If you hap- pen to set the D7000’s shutter to a faster speed in S or M mode, the camera will auto- matically adjust the shutter speed down to 1/250th second as soon as you flip up the flash (or prevent you from choosing a faster speed if the flash is already up). In A, P, or any of the Scene modes, where the D7000 selects the shutter speed, it will never choose a shutter speed higher than 1/250th second when using flash. In P mode, shutter speed is automatically set between 1/60th to 1/250th second when using flash.

But when using a non-dedicated flash, such as a studio unit plugged into an optional accessory hot shoe adapter, the camera has no way of knowing that a flash is connected, so shutter speeds faster than 1/250th second can be set inadvertently. To avoid that prob- lem with studio flash, I strongly recommend setting your camera to Manual exposure, and using the x250 shutter speed, which is located past the Bulb speed when rotating the main command dial all the way to the left. You won’t have to worry as much about accidentally changing the shutter speed to an unusable setting; there is no speed beyond x250th second, and if you nudge the main command dial to the right, you’ll get a Bulb exposure, which will immediately become evident.

Note that the D7000 can use a feature called high-speed sync, described next, that allows shutter speeds faster than 1/250th second with certain external dedicated Nikon flash units. When using high-speed sync, the flash fires a continuous serious of bursts at reduced power for the entire duration of the exposure, so that the illumination is able to expose the sensor as the slit moves. HS sync is set using the controls that adjust the compatible external flash.

High-Speed (FP) Sync

While the D7000 prevents you from using a shutter speed faster than 1/250th second when working with the built-in flash, if you use certain external dedicated Nikon flash units, you have an additional option: high-speed (FP) sync. You don’t need to make any special settings on the flash; the D7000 takes care of the details for you, as I’ll describe in this section.

As I said earlier, triggering the electronic flash only when the shutter is completely open makes a lot of sense if you think about what’s going on. To obtain shutter speeds faster than 1/250th second, the D7000 exposes only part of the sensor at one time, by start- ing the second curtain on its journey before the first curtain has completely opened. That effectively provides a briefer exposure as a slit of the shutter passes over the sur- face of the sensor. If the flash were to fire during the time when the first and second cur- tains partially obscured the sensor, only the area defined by the slit that was actually open would be exposed.