During a recent shoot I noticed this.  I'm thinking it just my sync speed due to my speedlight.  I included the exif to see if anyone can confirm this.  I have never experienced this before.  However, this is the first time I've  used my SB-700 in these conditions.  Any suggestion on weather or not i should have my D7100 serviced or the Promaster 17-50, 2.8f.  I know if it's the camera, it's still under warranty.  But if it's the lens, I'm SOL, because I believe it would cost more to fix than just buying a new lens.  Anyway, Here what happened.

My guess is that the lens has a petal lens hood and that it came loose and slipped by approximately 45 degrees.RegardsPaul

This only happened to 4 photos out of about 175.

rntbot wrote:During a recent shoot I noticed this. I'm thinking it just my sync speed due to my speedlight. I included the exif to see if anyone can confirm this. I have never experienced this before. However, this is the first time I've used my SB-700 in these conditions. Any suggestion on weather or not i should have my D7100 serviced or the Promaster 17-50, 2.8f. I know if it's the camera, it's still under warranty. But if it's the lens, I'm SOL, because I believe it would cost more to fix than just buying a new lens. Anyway, Here what happened.I assume you're speaking to the dark corners. At that wide angle I wonder if your lens hood being on wrong might be the issue. Corners are almost to defined for that, but still the most likely issue. If a shutter blade issue, should show up regardless of flash, I think, at same shutter speeds. I would use manual exposure mode and try to duplicate so you can maybe troubleshoot better.

Make the hood click, may take a little force to do that.Nothing wrong with your lens or your camera. And certainly nothing wrong with the model in the picture

If the longer petals on the lens hood are not top and bottom, the hood is not on properly.remove it and carefully replace it looking at the index marks.  You may need a bit more pressure at the end of the twist but be careful that it is not cross threaded.  The hood should slide on completely and straight to the lens before you twist.

Lens hood is not on completely.  I've experienced this same issue on my Tokina 12-24.

Has the shutter speed of 1/640 exceeded the flash sync speed? (i.e. visible shutter curtains)

Hood is on wrong.

As others have written, it's most likely the lens hood.Therefore why not spend a few seconds doing a little experiment? Turn the hood to an oblique angle and fire off a couple of shots. Then look at the result!It's not rocket engineering.