Hello, I am trying to use the rear sync flash on the D7000. I am trying to set it up in M mode on bulb setting or say a 20 second exposure. I have read the manual on page 145 and the flash is set to rear as shown in the LCD display. When I press the shutter the camera fires a small flash at the start of the exposure and a stronger flash at the end of the exposure. I don't want the initial flash firing only the rear curtain at the end of the exposure. Am I missing out on another setting somewhere?
#1. "RE: Rear sync flash" In response to Reply # 0 Mon 25-Feb-13 01:41 PM by jbloom
When using TTL mode, the flash has to fire a metering flash to determine the proper amount of flash power to use. One way to eliminate that is to use a non-TTL flash mode. If you are using pop-up flash, that means going to manual flash (CSM e3). If you are using an external flash, you may have other options, such as having the flash itself adjust exposure.
You can also use FV Lock. That performs the TTL metering flash at the time you push the FV Lock button (whichever control you have configured to be FV Lock). Then you can fire the shutter at any time and get only the illumination flash -- no metering flash. Of course, if you then move the camera to a different distance from the subject the flash exposure will need to be reset via FV Lock.
Edit: I should probably add that the TTL metering flash is performed before the shutter is open -- even before the mirror is raised. So if your concern is that the preliminary flash will expose the image -- it won't. But there are other reasons why you might not want that preflash to happen.