Looking for.

courtany · Post by **courtany** » Tue Jan 14, 2014 12:47 pm

I have been trying to search for a post that explains how to stop a flash operating twice when using mirror lock up on a stackshot. I think it appeared sometime last year in the equipment section but I can't seem to locate it. Thanks for any help.
Cheers Keith

rjlittlefield · Post by **rjlittlefield** » Tue Jan 14, 2014 2:38 pm

Sorry, I don't remember that posting. Let's try this from first principles...

The flash is controlled by the camera, not the StackShot. So apparently your camera is triggering the flash on what you're intending to be just mirror-up. This is definitely strange behavior.

What type of camera and flash are you using? Is the camera in live view when this happens? Have you confirmed that you're getting only one exposure for every two shutter pulses?

--Rik

johan · Post by **johan** » Tue Jan 14, 2014 2:51 pm

Hmmm, a flash operating twice usually indicates a *TTL type exposure I think. Do you have a way of using a different flash mode?

rjlittlefield · Post by **rjlittlefield** » Tue Jan 14, 2014 3:00 pm

Good point. I had assumed the flashes were far apart. Of course even that could also be explained by *TTL combined with a second curtain sync and long shutter time.

For stacking you should be running your flash in manual mode if at all possible. With any metering mode, there is increased opportunity for varying exposure from frame to frame.

--Rik

Yousef Alhabshi · Post by **Yousef Alhabshi** » Wed Jan 15, 2014 4:06 am

I think he's using Nikon camera? I used to face the excat issue with my camera body (D7000).

I can't remember if i managed to get over it or not.. as I'm not using the MLU anymore. I got to check it & confirm.

ChrisR · Post by **ChrisR** » Wed Jan 15, 2014 4:21 am

Well spotted Yousef. Nikon D700.
There's something I also can't quite remember in the Flash settings on the camera. Turn off any "modelling" from the pop-up flash, set everything to manual.

courtany · Post by **courtany** » Wed Jan 15, 2014 7:14 am

Thanks for the replies folks as soon as I read Riks reply I knew what I had done. I left the SB900 set on TTL and that causes the flash to fire when the mirror goes up an again when you take the shot. I use both Nikon D700 and the D800 and the same happens on both of them. So the answer is don't use TTL with mirror up mode especially if your trying a stack. And as I now recall that was the conclusion in the post I was trying to find. Thanks for the help.

Cheer Keith