Performance and Autofocus

Like the G7 X before it, the G5 X gets mixed reviews in terms of performance. It starts up quickly and has respectable focus speeds, but disappoints when it comes to continuous shooting, autofocus tracking and battery life.

Autofocus

The G5 X's autofocus system can best be described as confusing, both in terms of Canon's nomenclature and how it functions.

There are two 'AF methods' (typically called 'AF areas' on other cameras) available: face detect + tracking and 1-point. The former detects faces or, if it doesn't find any, uses multiple areas to lock focus (but only in One Shot mode, described below). In 1-point mode you can position the focus target wherever you wish and adjust its size (small or normal) by using the front dial.

ISO 125, 1/800 sec, F1.8, 24mm equiv. Photo by Carey Rose.

There are also two autofocus drive modes: One Shot and Servo. One Shot locks the focus as soon as the shutter release is half-pressed, while Servo will keep on focusing as long as the shutter release is half-pressed (but with some caveats).

That brings us to subject tracking - the ability of the camera to follow your subject around the frame. Note the camera is only capable of doing this prior to actually shooting. Of the four combinations of AF area and AF drive modes, only the Servo modes will continuously focus on your subject as long as the shutter release is half-pressed. The One Shot / Face Detect + Tracking mode will only continuously refocus on faces as long as you don't press the shutter at all. All of the Face Detect + Tracking modes appear to experience a 2-3 sec delay when continuously refocusing on a tapped subject that is not a face.

The only mode that keeps focusing after you hit the shutter release is the Servo AF / 1-point combo, which means that it can try to keep moving subjects in focus while shooting continuously. Being a 1-point mode, you need to position the AF point on the subject before you start your burst. One big issue with shooting continuously in this mode is that the focusing box will disappear as soon as the burst starts. So, if your subject moves and you need to recompose, you can't see what you're doing. Secondly, the JPEG burst rate is 4.2 fps when shooting continuously with Servo AF, rather than 6.4 fps with One shot AF. The burst rate may drop further if there's a lot of subject movement that requires significant refocusing.

If you're scratching your head after reading that, this table may clear some things up:

  Face detect + tracking 1-point
One Shot AF • Face detected: track
• Tap-to-focus: track (3 sec delay)
• Otherwise: multi-area AF

Focus locks on half-press		 • Movable single point

Focus locks on half-press
Servo AF • Face detected: track
• Tap-to-focus: track (3 sec delay)
• Otherwise: center point

Focus locks on shutter release		 • Movable single point

Focus continues while continuously shooting... but AF point not displayed when burst starts

As a demonstration of how the G5 X performs in the one mode that does allow continuous depth tracking while shooting, we offer up our world famous bike test.

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We shot this straight-on sequence three times (we didn't do the 'swerve' version of this test, as the G5 X cannot track in that way). We had to increase the ISO a bit in order to keep our shutter speed short, hence the noise. The first attempt was a total bust, while the other two had a hit rate of about 68% percent - not a very high hit-rate for a single, centrally located subject, and far worse than what the Sony RX100 IV is capable of at a higher burst rate to boot. As mentioned above, the focus point disappears when continuous shooting starts, so there's no way of knowing what the camera is focusing on.

So what shooting mode should you be using? Definitely not the default, which is 1-point / One Shot AF. For general use, we found that Face Detect + Tracking combined with One Shot AF is best for most purposes. It'll keep faces in focus as they move around, can track objects you've touched (albeit slowly), and revert to multi-point if neither of those two situations occur. Hence, it's fairly robust.

However, as it's name implies, your focus locks after one shot or a half-press, so if your subject moves between the focus lock and the shot, it may be out of focus. You may wish to switch to Servo with Face Detect + Tracking to shoot an active toddler (though it will only be a single shot and not a sequence). If you do want to shoot continuously with full-time autofocus, use 1-point combined with Servo AF, though keep the limitations mentioned above at the back of your mind.

Continuous shooting

Speaking of continuous shooting, the G5 X gets mixed reviews. When shooting JPEGs, it can fire away at a respectable 6.4 frames per second without AF until your card fills up (we used a very fast SanDisk UHS-II card to test speeds), though the RX100 III can shoot at 10 fps with the same settings. The camera doesn't perform nearly as well when shooting Raw, where the frame rate drops to a sluggish 1.2 fps. The frame rate is just 0.8 fps if you combine Raw and Superfine JPEG.

Battery life

One last performance thing to note is battery life, which is also below par. The included NB-13L lithium-ion battery contains just 4.5Wh of energy, which translates into a paltry 210 shots per charge (calculated using the CIPA standard). By comparison, the similarly priced Sony RX100 III can crank out 320 shots on a single charge, also using a 4.5Wh battery.