When photographers shot with 35mm film, they would get 24 frames or 36 frames, depending on the number of frames you purchased in a film canister. Someone (Olympus) popularized the half-frame concept in their film PEN models: the cameras exposed only half the frame to get twice the number of shots. So, instead of 24 full-frame or 36 full-frame shots, you’d get 48 or 72 half-frame shots.
But, since Fujifilm has not indicated a return to 35mm film production (except for continuing to produce its successful smaller sized instant films), we surmize this will be a digital camera. This would probably target the creation creators with Fujifilm’s own popular Film Simulations front and center (see the indicator on the left side at the back of the camera touting that the PROVIA film simulation has been selected).
Now, if it is digital, we already have APS-C, which is more or less half-frame already, so it cannot simply be sensor size or capture size. Instead, rumors (and these are only rumors) are that Fujifilm is going to use a 1-inch sensor and mask off (or turn them off or simply throw the light information away) half of the sensor and position it so that the light from the lens falls straight onto the unmasked half. Compose on a vertical LCD display and take a picture so that an image is captured on only the unmasked half (hence “half the Size”). Then, switch to mask off the already “exposed” half and move the sensor so that the other unmasked half is now facing straight at the lens. Take a second photo on the unexposed half (hence “Twice the Story”). The result is one single horizontal picture that is comprised of two vertical images side by side: a diptych image that allows you to tell a story with two similar or related images side by side. (See Banksy’s Girl with Balloon as a creative example.)
Another cheaper and simpler way is to simply place the 1-inch sensor vertically inside the camera. Take two pictures and virtually stitch them together side by side in-camera to create the diptych image… meh, less interesting and dramatic.
Now, of course, photographers could do — and have done — all that diptych-ing in post-processing, but the trend is now to do everything in-camera, and so behold the Fujifilm X-Half! Official announcement will probably be on Thursday May 22.