How bad is the Nikon J1 AF?..............

Started Nov 17, 2012 | Discussions thread
Veducci
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Re: How bad is the Nikon J1 AF?..............
In reply to bibi0012, Nov 18, 2012

bibi0012 wrote:

From dpreview:

"The J1 and V1 feature an all-new adaptive AF system that Nikon is calling 'Hybrid' AF. Hybrid AF incorporates both contrast-detection and phase-detection focus technology - the latter being used when the cameras detect favorable lighting conditions. Assuming that the light level is high enough, then the J1 and V1 switch to a 73-point focal-plane phase-detection AF system that offers fast and responsive 'single-shot' AF and impressive continuous AF tracking performance.

The switch to phase-detection AF depends on the amount of light falling onto the cameras' sensors, which is dependant on lens aperture as well as ambient light levels. In our testing, at the long end of the 10-30mm kit zoom (which has a maximum aperture of 5.6 at 30mm) the switch happens at brightness levels between 9-10EV, which is roughly equivalent to a dull overcast day. At f/5.6, if the light is lower than 9EV (approx) AF is driven using a contrast-detection system, and at roughly 10EV and above, phase-detection AF is used. With the 10mm f/2.8 pancake lens (currently the fastest lens available for the 1 System) phase-detection AF is available in lower light - down to approximately 3EV by our measurements (equivalent to dull interior artificial lighting).

Phase-detection AF is a particular gift for the 'soccer mom' and indeed anyone who finds themselves regularly needing to capture moving subjects outdoors, albeit one of the many aspects of the cameras' feature set which cannot be manually controlled. This sequence of images shows a 10-frame burst at 10fps, shot on the V1 in AF-C mode using the 1 NIKKOR VR PD-Zoom 10-100mm f/4.5-5.6. As you can see, the camera's hit rate is impressive.

The intended audience of the J1 and V1 are unlikely to take them to any major sporting events, but this doesn't mean that their innovative hybrid AF system is pointless. The J1 and V1 are the first mirrorless cameras that we'd be truly be confident about using to capture moving subjects, and potentially this means anything from boisterous children and pets to school sports days and weekend soccer games. The naturally deeper depth of field provided by their 1-inch sensor format and correspondingly short focal length lenses helps of course, but even taking this into account, we're genuinely impressed, especially by tracking accuracy with phase-detection AF.

The J1 and V1's contrast-detection AF systems, which take over when light levels are too low for effective phase-detection AF (and remember that this is the camera's decision, not the photographer's) are less impressive. Focussing is less positive (AF wobbles quicklyaroundthe target rather than locking straight on it) but impressively accurate when it gets a 'lock'. The problem is that even in average interior room light, both cameras struggle to find that lock. They rarely give up completely (and built-in AF illuminators are on hand in both cameras) but we've been surprised by how frequently they falter."

I read all this. In all the other reviews on the camera none were as negative about the AF in low light as he review here. Most were quite positive.

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