D700's built-in flash fires flashes in commander mode

Discussion in 'Nikon' started by benjaminm, Feb 3, 2010.

  1. My D700's built in flash suddenly began to fire flashes in commander mode. I think the built-in flash shouldn't fire any flashes in commander mode in combination with a SB-800 as remote unit. Am I wrong?
    D700 settings: e3=commander mode, Built-in flash mode= --, Channel=1, group A=TTL, comp=0
    SB-800 settings: remote, channel=1, group=A
    Thanks in advance,
    Benjamin
     
  2. The pop-up always has to flash, so that it can communicate with the slave(s). There will be a couple of metering pulses before the exposure, and a small flash during the exposure. In most cases, it won't matter, since it's not contributing meaningfully to the exposure when you have it set to '--'. But if you're shooting something highly reflective, you might see a specular reflection from the pop-up. It's also possible that you'll get some subject blinking from the pop-up's pre-exposure activity, if they have good reflexes (I see it more in dogs, than people!).

    One solution: the under-$15 Nikon SG-3IR, which blocks all but the infrared emitted by the pop-up. Otherwise, it's an SU-800 in the hot shoe. Or radio triggers.
     
  3. Matt,
    yes, the flash light in '--' mode really differs from the flash light in TTL mode. But as you said, for serious use I'll have to buy an SU-800 unit.
    Thanks,
    Benjamin
     
  4. The pop-up emits mostly visible light both for flash and to communicate. Use the SU-800 if you want a more discrete i-TTL remote system.
     
  5. pge

    pge

    You can always just turn the onboard flash way down to the point where it doesn't effect your exposure much, you will still see it in the eyes but the sb-800 will be much larger, assuming you are taking photos of something with eyes.
     
  6. Built-in flash mode= -- and a shutter speed of 1/320 in FP mode. The built-in commander will send the sync pulse before the first curtain opens and won't appear as highlights anywhere.
    Instead of firing the remotes once when the shutter is fully open, FP mode works by rapidly strobing as the shutter curtain slit moves across the sensor. So the only way the commander flash can send an appropriate sync pulse is to do it before any of the sensor is exposed.
    It's simple to test this by triggering a remote while pointing the camera at a mirror. Shutter speeds 1/250 and below will show the commander flash going off. Shutter speeds above 1/320 won't show the commander flash. You can see some shots I did to demo this at the following posting - http://www.photo.net/nikon-camera-forum/00NjiR
    But as previously mentioned, the SG-3IR and SU-800 are better solutions.
     

Share This Page