Dual IS

An illustration of the dual IS system, courtesy of Panasonic.

Dual IS is one of the most compelling features on the Lumix GX8. In short, it combines the camera's sensor-shift shake reduction with the optical stabilization of compatible lenses.

For stills, the GX8 combines its onboard 4-axis shake reduction with the 2-axis IS from compatible lenses. For video, only the lens' IS does the stabilizing, with the camera adding 3 axes of digital shake reduction. Image courtesy of Panasonic.

From a more technical perspective, here's how it works. The GX8's in-body stabilizatiion system can compensation for translational (X and Y) movement as well as rotational pitch and yaw (so that's four axes in total). Most lenses can only correct for pitch and yaw.

With a stabilized lens attached you get the benefit of having the yaw and pitch correction from both the lens and the body, with the in-body IS system continuing to handle the X and Y axes. Panasonic says that the Dual IS system is 3.5x and 1.5x more effective at wide-angle and telephoto, respectively, compared to the GX7 that preceded it. It's worth noting that much of the improvement at short focal lengths is due to the fact the GX8's in-body stabilization can counter translational movement and the GX7 could not.

Where Dual IS shines is with longer lenses, where pitch and yaw cause the most problems, as sensor-shift systems (such as what's in the Olympus PEN-F) cannot move far enough to correct for movement along those axes. Since the GX8 has both the lens and sensor-shift IS systems correcting for pitch and yaw, stabilization will be better than either on their own.

Dual IS on (200mm equiv.) Dual IS off (200mm equiv.)

In our tests we found that the GX8 gives you about 3 stops of stabilization at telephoto focal lengths (200mm equiv. in this case). In real-world terms that means you still get the majority of shots in-focus at ~1/60 sec with IS compared to ~1/320 sec without it. That's not quite as good as the 4 stops we measured on the Olympus PEN-F.

We did run into some anomalies when testing the GX8's IS system, where the 'hit rate' (number of sharp photos) dropped precipitously at certain shutter speeds, such as 1/125 sec in the example above. We believe this could be due to shutter vibration causing shake which has some kind of interaction with the IS system. Indeed, in both our studio testing and the real world we found this 'shutter shock' phenomenon to be an issue (though Panasonic has included a work-around).

Mechanical shutter (200mm equiv.) Electronic shutter (200mm equiv.)

One way to avoid this 'shutter shock' is to use the camera's electronic shutter. As the above chart illustrates, it gives a much higher percentage of sharp photos, which is especially noticeable at 1/125 sec, where we deemed 90% of the photos as 'excellent', compared to the mechanical shutter, where 70% of photos had 'some softness' and the rest were 'blurred'. While it sounds tempting, using the electronic shutter has downsides, most notably the possibility of rolling shutter when shooting fast-moving subjects and the inability to use the flash. Panasonic has come up with a clever workaround (that we wish wasn't necessary in the first place) that you can read about on the next page.

4K Photo

One of the GX8's most-touted features is 4K Photo. Simply put, the camera will use its 4K capability to capture short clips (though not necessarily in the 16:9 aspect ratio of its video footage) from which you easily extract 8 Megapixel stills, which makes reduces the amount of 'luck' needed to capture that perfect moment. The interface for selecting the photo you want is clever, involving just a slight drag of your finger.

Above: from this very short clip you can pull out an 8MP still like the one below. (Be sure to increase the resolution of the video to 1080p or 4K for optimal viewing)

Here's the clip pulled from that video using the tool on the camera (it's very intuitive). It has a bit of that 'frame grab' look, but still, very nice.

There are three modes: '4K Burst' keeps firing while the shutter release is held down. '4K S/S' starts when you press the shutter release and stops when you press it again. '4K Pre-burst' is constantly buffering and will record the second before and the second after you press the shutter release. This last mode is the only one in which continuous focus is available.

As for the quality, it's not great. Good enough for Facebook and e-mail, but not something you'll want to show off in your art gallery.

Post focus

A very cool feature, which was added to the GX8 via a firmware update, is Post Focus. While not nearly as high-tech as what Lytro has done with its Light Field camera, the results aren't that different. After recording a video during which the camera racks focus across the depth of the scene, users can then tap the area on which they wish to focus with the rear screen, and then save that frame. Ideally you want to keep as still as possible during capture, which takes a second or two, but even with slight motion, Post Focus still works very well.

Focused on the glass Focused on the ketchup bottle Focused on Dan

Post Focus is a very cool (not to mention useful) feature that Panasonic should be commended for adding to its cameras. One thing to note is that Raw mode will be turned off while Post Focus is active.