Man, I really hope a firmware upgrade could allow 100% zooming to check image sharness on the ZD. I really don't see the point of the current zoom function. Right now, you just have to hope, unless shooting tethered.
I just gave my ZD away for a factory firmware upgrade this morning. I'll get it back on Friday 15th. I am not sure what exactly the latest firmware brings, we'll see.
In fact, I wasn't really sure what the initial firmware level was, only that it wasn't the latest.