How good is the new AF module in D7000

<p>I have seen many many posts here and in other places showing how good the D7000 is in low light. However another major feature in the D7000 is the new AF module, but no one has reported anything on that. Is it as good as the one in the D300s and how much better is it than the one in D90, in terms of the ability to AF in low light and to track moving objects. </p>

<p>good question, I will follow this thread because I am waiting for the launch of D7000 in my home country.</p>

<p>It shouldn't be that hard to guess that the D7000's Multi-CAM 4800 will perform somewhere between the Multi-CAM 1000 (D200, D80, D90, D3000, D5000, and D3100) and the Multi-CAM 3500 (D300, D300S, D700, all D3 family).</p>

<p>I think the problem with the D7000 is that all 9 cross-type AF points are in the center of the frame. Under low-light conditions, if your subject is off center, it may be a problem.</p>

<p>To Shun's point, I've observed better AF performance on my D90 with the 1 center AF point than with the others. Somehow, when I use off-center points, I get more shots that are soft or simply out of focus. If I am photographing action, the best choice seems to be to use that center AF sensor and then crop. It would be better if the left and right sensors were also cross type. When I try to get a shot of a single rider (bicycle racing), I switch to one of the off-center sensors and go portrait mode so the sensor is on their face, but the non-cross AF points are not as dependable.<br>

The D7000 claims 9 cross type sensors, all in the middle. The D300S claims 15, also in the middle.<br>

I think what we really need is 3, not a cluster in the middle.<br>

OK, all this is theory. I'd be interested to hear real shooting experience.<br>

Trying to think this through from a semiconductor perspective, the cost of a chip is set by its die area and the features or process steps required. I understand why the FX cameras just leverage the DX AF technology; it minimizes die area. What we really need is well-spread AF sensors. I don't understand why cross sensors have to be limited to the middle. If they can make one, they have the process technology. If they can put non-cross sensors at the edge, they are spending die area. Why not build an AF module with fewer AF sensors but make all of them cross-type?</p>

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<p>Why not build an AF module with fewer AF sensors but make all of them cross-type?</p>

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<p>There is one: Canon 7D AF module - 19 AF sensors all cross-type. :))</p>

<p>Nikon described in the introduction of the D3/D300 that they put the cross-type sensors in the center columns because according to their research most subjects to be tracked tend to be near the center and making all the sensors cross-type would produce too much information that would confuse the dynamic tracking (51-point thing). Anyway, that was their excuse. For people like me who normally use a single point or 9-point mode it would not be a problem. The 51-point focusing system is in my opinion not worth much in its current implementation, so sacrificing the functioning of focusing points outside of the center to get it to work was not a good decision.</p>

<p>Nonetheless with the Multi-CAM 3500, even though most sensor points are linear, I'm happy with the way it works apart from the very cornermost points which tend to be jittery and produce unreliable results. I have no information about the D7000.</p>

<p><em>Nikon described in the introduction of the D3/D300 that they put the cross-type sensors in the center columns because according to their research most subjects to be tracked tend to be near the center and making all the sensors cross-type would produce too much information that would confuse the dynamic tracking (51-point thing). Anyway, that was their excuse.</em></p>

<p>That is consistent with Canon placing dedicated AF CPUs in the 1D series and 7D bodies.</p>