I experienced a problem with my D70s that I heard reported round these parts. I was clik'n away at an audition when the mirror froze mid-flight blanking my viewfinder and generally freezing my shutter and displaying "ERR" on the top-left corner of the LCD screen. Nothing would release it. Not powering down, not removing the lens, not removing the memory card, nothing. I switched bodies and my brother took my camera and as he was looking at the "ERR" message, it cleared of it's own accord. I did a search here and found another person who experienced the same problem. However, this other person waited until it happened several more times. I called Nikon USA and they told me the following. "It is recommended that the camera come in to Nikon Service for evaluation to determine the cause of the mirror hang. It may be that it may not do this again, but it would be prudent to have the camera checked out to ensure that it will not happen again." I sent it out that day. I was told that the turn-around was seven to ten days. I'm crossing my fingers, I hate being with only one camera and I don't want to break out the film. I don't know if this is a common problem, but I wanted to post this in case it is and so others can benefit from my experience.