7D + PW Shutter Curtain Mishap???

I just purchased a 7D, got a feel for the settings, then popped on my pocketwizards (miniTT1, flexTT5) using a 430exII speedlight. I took a couple of shots, things were fine and dandy, then sporadically some shots would be dark from top down about midway, almost the same effect as when using a shutter speed faster than the max flash sync speed, hmm...

I have found 2 issues pertaining to this:

1) As I raise my ISO, it shows more prominently.

2) As I tilt my camera upward it shows more prominently, almost as if the curtain is falling.

I think there may be something screwy with the shutter, but I'm sure someone may be able to correct me if I'm wrong

*Note* This only happens when using the PWs. When the 430exII is mounted to the camera, everything works fine.

I'm thinking that I should return the camera and trade it for another, as I just bought it yesterday.

Has anyone ever heard of this happening?

Some radio triggers are a little slow, so you can't get max sync speed out of them. More than likely this is what you are running in to. Amusingly, I had the same experience with PWs but my cheapie Cactus V4s work perfectly at 250 with my 7D.

I doubt it's the camera causing the problem. Probably the pocket wizards are to blame I would guess. I'm guessing that as you raise your ISO or point the camera up (towards the sky I'm assuming), your shutter speed is increasing causing the problem to show up more frequently. Are you allowing the flash to completely recycle between shots?

Oh yeah, get it out of Av mode too. Sounds like that's what you're doing. Put it on M if you're going to be using off camera flash.

Whats your shutter speed?

I guess I should have mentioned that I am using manual mode (including manual ISO setting), shutter speed set to various speeds: 1/30, 1/60, 1/80... I have tried it all. I have varied all sorts of combinations and it doesn't seem to change anything.

I've used my PWs with my t1i and never had this issue, still don't have this issue when I use it on the t1i now.

I'm sitting in my room, used low light, ample light, and no light: still to no avail. I've used it outside as well at late sunset, still to no avail.

Here's another weird part: when I crank the shutter speed up to 1/400 and faster, there are no issues!!! I don't get it.

Is your flash on HSS?

Nope.

Problem Solved!

In the PW Utility, under "misc", the camera was set to t1i, I changed it to auto and everything now works perfectly.

I'm not sure why it worked, but it did correct the problem.

Thanks for the input!

glad that solved the problem... i've got a couple PW's that should be here friday and was planning on running them from my 7d

I have been using my pixel kings and 2 YN560's with my 60D for a couple months, I shot 1000+ pictures without a problem. Today I used 7D first time with the same set-up, one every ten pictures have the same problem. There is a dark (10-20% of the height) area at the top of the pictures.
If it was on the sides (vertical dark strip) I would say synchronization, but as far as I know curtains are moving side ways, not up and down, right ?
Never had any problems with 7D before, but I am using 7D mostly outdoors without flash. (using more than a year)

I am using Manuel mode, shutter speeds less than 1/200.

Any ideas ?