This latest incarnation of Fujifilm’s Super CCD sensor, used in the FinePix F300 EXR, has an intriguing new trick up its sleeve: it uses some of the photosites on its 12-million-pixel sensor to allow phase-detection autofocus.
Unlike contrast-detection AF, phase detection works by splitting the light entering the lens into two. The two beams of light then create left and right images on the AF sensors. These images are compared and the lens adjusts according to how out of phase they are with each other. For an easy analogy, think of how a rangefinder camera is focused manually, except that in this case two sensors and a motor calculate the point where the two offset images will meet.
However, the ingenuity of the F300 EXR doesn’t stop there. It has a 15x optical zoom lens – the equivalent of a 24-360mm in 35mm terms – made possible through the use of what Fujifilm calls Double Sliding Structured Lens Technology. This basically means that two different internal lenses automatically slide into place to allow the wide or telephoto capabilities.