The Nikon V1 and Nikon J1 are the two debut models for Nikon's latest lens mount, their compact "1" system. Using a smaller sensor—dubbed a "CX" size, compared to the DX (APS-C) and FX (full frame) sensors in their full-size DSLRs—the two Nikon cameras both combine small lenses with a great deal of speed. As with the debut models of competing mirrorless systems, there are some new hitches, both in terms of performance and design, as these two models blaze a new trail for Nikon.
The Nikon V1 and Nikon J1 both incorporate some technologies that are new to interchangeable lens cameras for Nikon. The first is the mirrorless construction. Both cameras work similar to other mirrorless system cameras by displaying the image on the rear finder directly from the image sensor, rather than through an optical viewfinder. The Nikon V1 makes up for this by including an electronic viewfinder, which displays all the relevant shooting information from the rear display on the small eyepiece. The Nikon V1's EVF is quite good, easily among the better ones in this class of cameras, most of which only offer an EVF at a higher price point.
Nikon is already very well respected when it comes to DSLRs, but the recently announced Nikon V1 and Nikon J1 bring that down to a much smaller scale. The size of these new cameras is comparable to a Panasonic GF1, making them appear like compact point-and-shoots. However, much like the micro four-thirds system, the Nikon 1 Series is equally adaptable with a powerful 10.1-megapixel sensor, ESPEED 3 image processing engine, and interchangeable lenses.
This lack of a mirror has another major drawback: autofocus performance. The Nikon V1 and Nikon J1 get around this by incorporating a line of autofocus sensors onto the image sensor itself, rather than on a separate dedicated autofocus sensor. This provides phase detection autofocus when shooting with the rear LCD or during video, something only Sony's line of SLT (not their mirrorless NEX cameras) can offer. It's very accurate, though it does begin to struggle in very low light levels along with its peers.