Autofocus
Cameras that lack a mirror tend, on the whole, to rely on a system of contrast monitoring via the imaging sensor to drive automatic focusing. While this is the way focusing is managed in practically all compact cameras, as well as compact system cameras, it is a method that lags somewhat behind the phase-detection systems used in DSLRs. Nikon, however, has managed to incorporate a phase-detection system into the sensor of its V1 and J1 models.
Using dedicated pixels in lines across the sensor, the camera is able to switch between contrast- and phase-detection modes according to the lighting conditions. As the sensor is pretty small, the distance between the phase-detection pixels can’t be that great, and thus the ‘base’ of the system is probably somewhat shorter than in a normal SLR. Having ‘eyes’ closer together makes it more difficult to judge distances, but Nikon is still happy to claim that this is the fastest AF system in the world.
In good conditions, and actually in average conditions, too, I did find that the camera focuses very quickly, but in low light it struggles a bit. The degree of struggle is not unexpected, however, and I think it is fair to say that the V1 AF system works in light levels many others would not. Subject detection in close-focusing situations can be tricky, and macro focusing is not always straightforward. I found it frustrating at times to see the subject come in and out of focus without the camera being able to lock on, but in reality this is a very small issue. Where the AF system really shines is in its continuous mode, in which it discovers and tracks subjects or shifting distances under the AF point extremely quickly.
