Overall Performance

The Panasonic GH3 is generally a responsive camera, whether you're using hard buttons or the touch screen. It's only really in Wi-Fi mode that you'll experience any significant delays (the camera can take up to a minute to establish a connection with no indication that the process is going to be successful). You can find out more about the camera's Wi-Fi behavior later in this review.

Continuous Shooting and Buffering

The GH3 has a number of continuous shooting modes - a super high speed mode that shoots up to 80 4MP JPEGs at a rate of 20 frames per second, a high speed mode that shoots full-resolution images at up to 6 frames per second and two slower modes that offer 4 and 2 frame per second shooting. These last two modes are the only ones to offer live view updates in between shots.

In principle the full resolution modes allow continuous shooting up to the capacity of the memory card being used but a footnote in the manual acknowledges that the camera cannot maintain its full shooting speed for the entire duration.

Continuous High (without Live View between shots)

JPEG 16MP Large
Frame rate 6.1 fps 6.0 fps 6.1 fps
Number of frames 81 22 18
Buffer full rate 2.5 fps 2.0 fps 1.0 fps
Write complete 2.2 sec 20 sec 20 sec

Continuous Medium (with Live View between shots)

JPEG 16MP Large
Frame rate 4.0 fps 4.0 fps 4.0 fps
Number of frames 38 27 21
Buffer full rate 2.0 fps 2.0 fps 1.0 fps
Write complete 9 sec 11 sec 19 sec

All timings performed using a 8GB SanDisk Extreme Pro UHS-I SDHC card (90MB/s)

Autofocus speed / accuracy

Single AF acquisition is impressively fast - using most Micro Four Thirds lenses will result in some of the fastest focus on any system. The AF-F mode (that attempts to retain focus on a subject that moves) is less impressive.

The tracking system, can be a little reluctant to lock-on to a subject (such that we doubt it will achieve a lock in time to catch most fast-occuring events). Once locked the camera will attempt to re-focus with the subject but the results we got were pretty hit-and-miss, with the camera frequently refocusing onto the background or not keeping-up with the subject. On the plus side, when used in video, the camera is pretty restrained about re-focusing, so your footage is rarely undermined by unpleasant wobbly focus (though it will tend to shimmer in and out of focus if your subject stays still).

Ultimately, for stills, the continuous autofocus, while better than most older mirrorless cameras, still isn't up to DSLR standards and certainly isn't appropriate for video work if the output quality is particularly important.

Video showing the camera's continuous autofocus mode while shooting video. The camera's rear screen is being touched to specify the focus point and the camera is doing a very good job of transitioning between focus points with shimmer or unnecessary re-focus attempts.

However, in video, the behavior is different. If you disengage AF tracking you can instead specify the focus point as the video progresses. In this mode the camera will attempt to gently 'pull' focus from one position to the next. It depends on the lens, of course, but with most recent micro four thirds lenses, does a good job of moving smoothly from point-to-point, and seems pretty good at resisting the temptation of fluttering focus back and forth once it's found its target. The result is a pretty usable autofocus implementation that makes it easy to get good results from the camera even if you don't have experience of manually pulling focus.

Battery life

One of the great advantages of the GH3's increased size is that it can take an unusually large battery for a mirrorless camera. The 7.2V, 1860mAh battery give 13. 4Wh of power, 50% more than the OM-D's battery, for example. This give the camera an impressive battery life of around 540 images per charge or 270 minutes of recording time.

Better still, a battery grip is available for the GH3 for the first time - allowing longer gaps between having to change batteries.