Pre-Flash & FV-Lock

[CuriousOne]

I recently just purchased a Sb-700 to use for some off camera lighting for my D7000, and I'm having a hard time figuring out why my camera is pre-flashing once again after I've already set FV-Lock and have already fired to lock in the flash exposure on my speedlight. I have set my on-camera flash as commander with (--) settings so it doesn't interfere with the lighting coming off of the Sb-700. Thanks in advance!

P.S. I was attempting to take a few pics of my cat and trying to prevent him from blinking.

[Manfred M]

Have you have left the "red eye" reduction feature on? That is the only source of noticeable pre-flash I can think of.

Any of the Nikon CLS pre-flash is indistinguishable from the main flash (I shoot with both the SB600 and SB900), and have not used the SB700.

[PhotomanJohn]

I am a little confused but are you referring to the flash that the camera sends to the SB700 to actually trigger it for the exposure? I believe that if you want the internal flash not to affect the exposure then the shutter and the external flash delay slightly from when the trigger flash from the internal flash occurs. But the internal flash has to fire to trigger the external flash no matter what.

Agin, I may be confused as to what is occurring.

John

[Hero]

Set flash to manual. While in ETTL-mode it will still preflash to figure out the amount of flash that is needed. This is independed of the camera's metering settings.

[Mark von Kanel]

John what, i think manfred is saying is that when you use the flash in ttl mode the pre flashes are not distinguishable from the main flash, if you are getting visible pre flashes when using a single on camera flash, it is likely that its because you have red eye reduction mode set on you camera. If you have this set to on, then the flash will emit a number of flashes to try to reduce the subjects pupil size before the main flash fires.

On your camera settings panel on the top right of your camera body, do you have a picture of an eye next to the lightning bolt that says the flash is on? if you do then hold down the flash button (front left of body) and rotate rear cmd dial until it goes. that will remove the red eye reduction and should stop your pre flashes.

If your problem persists it may be because you have the flash in commander mode and its signalling exposure info to imaginary flashes (but i dont know if the sb 700 does this i only have sb900).

get back to us if you need more help

[Manfred M]

Thanks Mark - that is exactly what I meant.

Thinking about it a bit more; CuriousOne could also be referring to the autofocus assist lights; there is a white light one on the camera and a second one that uses red LEDs on the flash itself. I tend to have these "features" disabled on my cameras / flashes because I find that they annoy the subject, so normally don't think about them. If either of these fire up, it would certainly be enough to annoy the cat. The camera one can be disabled via a menu item and the one in the flash can be turned off as well.

There is also another function in the camera; the "modeling light" that should be disabled as well. This fires the flash (both the built in and the off camera flash) to simulate a modeling light found in a studio strobe. If this is one, it will certainly annoy the cat (or any other living creature) and drain your batteries more quickly as well. If this "feature" is enabled, it could be the cause of the issue as well.

I've never used the FV lock; it is a feature that I have never found a use for.

[CuriousOne]

Thanks everyone for your great advice. I think John answered my confusion about triggering the external flash when he said that the internal flash has to be fired to trigger the external flash. I was under the assumption that I don't need to trigger the external flash again after I have activated the FV-lock. As for the red-eye reduction, I was shooting on manual mode and the internal flash is set to fill light which does not interfere with the SB700 because my camera's flash is only set to be the commander.

I was just confused as to why I've been reading that FV-Lock prevents blinking and pre-flash when I would still need to fire the internal flash to trigger the the SB700.