I have actually asked the same question in the LR forum... Here it goes:
I have seen this done before but have forgotten how it's done. Scott Kelby showed it in one of his tutorials: He'd zoom in part of the image and then with a combination of keys, he'd "skim over" the whole image, area by area, from top to bottom and left to right.
Does anybody know how to do this? It may be on LR or on PS....
Try your home, end, page up and page down keys with the modifier keys (ctrl, alt, shift or cmd, opt, and shift)
Yes, that did it. I remember now. The issue is that on my iMAC I'm using one of those wireless keyboards and they do not have all the keys, but could do so with the Fn + down arrow key.
Thanks a million buddy,