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Hi --
I'm having a hard time getting consistent flash exposures out of my D4 + SB900 + PW setup. Most of my shots will be properly exposed, but then some (maybe 25-30%) will be totally overexposed, as if the flash is firing on full power. Does anyone else get this? I don't know if this is an equipment issue, a configuration thing, or something in how I'm using them. But it's really annoying, and I've been unable to figure anything out.
An example is below. Both shots were on Aperture priority, f/2.8, EV=0, FEV=0. Matrix metering. Both metered at 1/15th, ISO 400. They were taken within a second of each other. AF-C, with a single focus point set.
But the second one is obviously way overexposed!
At first I thought that the frame shifted a bit, so the flash was metering off of something in the background, rather than the foreground. That would cause a foreground overexposure. But I was unable to force the flash system to overexpose when I was trying to do this intentionally. And my understanding of Nikon flash metering is that it always meters on the foreground / center anyhow, so a minor shift shouldn't change that. (e.g., http://nikonclspracticalguide.blogspot.com/2008/02/8-how-buit-in-flash-metering-works.html).
Then I thought that maybe it was a hardware issue. I used to have full-power exposure on my Canon flashes when they were not fully plugged into the hotshot. But I get the same behavior with both the SB800 and SB900, so that seems unlikely.
Then there's the PW's, which are always a bit dodgy. But there is nothing complex here and they should be able to do the job. I'm not shooting at 1/1000 on hypersync or anything. I'm using two TT5's, with a zone controller. Powering everything down and back up does not fix the problem.
So maybe it's me, or my mis-understanding of how flash metering should work. Ideas?
Thanks,
-Henry
P.S. I've looked at the EXIF data and there is nothing relevant there. The flash power is not listed -- only that it was on and fired.
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