> How can I be bracketing when I press the button once and I only get one image?
Very easily, since that's actually how bracketing works. It does NOT automatically shoot all shots in a bracket. The exception is if you've set Cl or Ch mode AND press the shutter down AND HOLD IT for the ENTIRE duration of all of the shots. It is VERY common for people to ask about "wildly varying" "random" exposures only to discover that they have bracketing set. Normally when bracketing is on, press the shutter release once and it takes the NEXT member of the bracket. It is a very confusing way to work, actually.
However, that isn't your problem.
The next thing for you to check is to ponder why the exposures are wildly overexposed. I can think of two different ways this could be happening. One would be that the aperture / shutter speed / ISO are set just as they were at 50mm, but you get far more light. That might happen if something about the zoom situation causes the stop-down mechanism to fail. To test this, set the camera in MANUAL exposure mode - at which point spot/matrix/CW doesn't matter. Meter at 24mm and set exposure. Shoot at 24mm, then at 70mm. Are they wildly different?
The other possibility is that the aperture reporting mechanism is broken. If this is the case, then the above test will NOT show any difference between 24mm and 70mm exposure, since in manual mode it does not matter what aperture the camera thinks is set; you're telling it how much to stop down.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!