Originally posted by monochrome What's that glass thing on the upper right of the Fuji?
That sir, is the optical/hybrid viewfinder.
Fujifilm X-Pro1 Hands-on Preview: Digital Photography Review
"The X100's signature optical/electronic 'hybrid' viewfinder is retained, and to help cope with interchangeable lenses it now offers two magnifications. At its lower magnification (0.37x) it covers the field of view of the 18mm lens; when the 35mm lens is mounted, an additional magnifier slides into place to match, giving 0.6x magnification. The 60mm lens uses a smaller frameline within this magnified view. One of the advantages of the hybrid finder, of course, is that it can project suitable frame lines in the optical finder for a wide range of focal lengths, and critically-accurate composition can always be obtained by switching to the EVF."
At least that's what I think it is.