Autofocus

The Lumix DC-GX9 is capable of acquiring focus rapidly and keeping up with a moving subject so long as you keep an autofocus area over it, but unfortunately, burst shooting during autofocus tracking (where the camera automatically tracks a subject around the frame) is less impressive. Overall, the camera's Depth-from-Defocus technology results in fast and accurate results for casual shooting.

Key takeaways:

  • Autofocus is generally fast and accurate
  • Autofocus tracking during burst shooting is acceptable, if not a stand-out
  • Using autofocus tracking and firing one-off shots is much more effective
  • Touchpad AF with Tracking is a powerful combination when using the EVF

In depth

The Lumix GX9 comes with contrast-detect autofocus with Panasonic's Depth-from-Defocus technology (DFD). What this basically means is that the camera is able to 'read' the out-of-focus blur to consistently drive its lens in the correct direction. Thanks to lightweight focus elements on all of Panasonic's current lenses, this means autofocus is very fast, with less of the 'hunting' that is common on other contrast-detect systems.

There are also some interesting interactions between autofocus and burst speeds on the GX9. When the camera is in Continuous AF, the maximum speed is 6fps - whether you select the 'H' or 'M' speed in your drive settings, the camera just fires at 6fps for both. Switching to Single AF sees the 'H' speed jump to 9fps though, of course, without autofocus. 'L' fires at 3fps in either mode.

Daylight autofocus performance

First let's evaluate how well the GX9 can detect the distance of an approaching subject and drive the lens to that location. For this we use a single AF area with continuous autofocus with the Lumix G 35-100mm F2.8 lens and shot at the maximum burst speed of 6fps.

A representative sample of our subject in-focus as he approaches the camera.

Over several runs, the GX9 turned in basically a 100% hit rate for the cyclist approaching the camera in a straight line. This is something we've grown accustomed to from Panasonic cameras, and it's nice to see the GX9 performs as expected here.

Next, we have the cyclist weave side-to-side as he approaches the camera. As far as the camera is concerned, this is fairly unpredictable behavior, and you can think of it as an analog for a child running across the grass toward a parent, or an athlete ducking and dodging their way across a field. This makes life more difficult for the camera as it has to recognize and follow the subject around, as well as assessing its distance.

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This representative sample shows how the GX9 did across a number of runs, with a hit rate hovering around 50%. However, this was also with the shutter release set to 'balanced emphasis,' meaning the camera is balancing between keeping the subject in focus and keeping its burst rate as close to 6fps as possible.

When we switched into 'focus priority,' things improved.

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Once in 'focus priority,' the hit rate jumped to just over 60%. Not a world-changing improvement, but an improvement nonetheless. We also didn't note a discernible change in burst speed, either - the camera seemed to stay at or very close to 6fps.

Lastly, it's worth mentioning that switching the burst speed to 'L' or 3fps saw a repeated hit rate of 100%.

Low light autofocus performance

Our next exercise is designed to see how the camera performs in a dimly lit social setting, such as a bar or restaurant. We used tracking with face detection enabled and disabled in continuous autofocus, and fired off single shots (i.e., no bursts).

Sample photoSample photoSample photoSample photoSample photo

As you can see, despite the challenging lighting conditions the GX9 fared really well, with only one image out of focus. You can also though see the characteristic 'wobbling' of continuous AF with Panasonic's DFD system.

Real world - shooting a concert

So, we've seen the GX9's continuous autofocus does great with bursts and a single area, and with single shots and tracking. But how does that translate into the real world, and how would you use the camera?

Processed in Adobe Camera Raw.
Lumix G Vario 35-100mm F2.8 @ 85mm | ISO 200 | 1/2000 sec | F2.8

We've already published a short piece on how the GX9 fares in this sort of situation, but here's the basic gist. Using tracking and Touchpad AF, the GX9 is a great concert companion, and got me plenty of keepers when paired with the impressively small Lumix G Vario 35-100mm F2.8. There's some shot-to-shot lag that was occasionally a pain, but the combination of compactness, image quality and AF accuracy was impressive.

Read the full Lumix GX9 concert
shooting experience