G1 X III versus G7 X II shootout

Introduction

In our review of the Canon PowerShot G1 X Mark III, we made some pretty bold claims. Namely, that the lens on the G1 X III makes such a compromise in terms of maximum aperture in an effort to keep the size of the camera down, that much of the theoretical advantage of the large APS-C sensor is basically moot.

Specifically, the lenses on cameras with smaller 1"-type sensors are so much faster in some cases that they have the potential to offer both better control over depth of field, as well as better noise performance in low light. The specs do tell us, though, that the G1 X III should offer better dynamic range at base ISO.

At 24mm, the G1 X III has a slight advantage over depth of field control compared to the the G7 X II, but either matches it or falls behind its smaller-sensored sibling elsewhere in the zoom range.

This is a pretty big deal. After all, the G1 X III is Canon's flagship compact, and is the only camera currently on the market with an APS-C sensor and a zoom lens (it also fits in your pocket). On the other hand, the G7 X II is nearly half the price, is more compact, and its smaller 1"-type sensor is potentially offset by a much faster zoom lens with greater reach.

Of course, this discussion is so far based on specification alone, and those specifications can't necessarily take into account real-world sensor and lens performance. So, let's check our theory, and see how these two cameras compare.

Bright landscape

This is the main situation in which you'd expect the G1X III to have an advantage. Assuming comparable sensor performance, we'd expect the G1X III's larger sensor to have greater dynamic range advantage, tolerating more light before clipping and thus allowing more exposure, which should give slightly cleaner tones throughout the image.

G1 X Mark III
ISO 100
F7.1 (F11.5 equiv)
1/320th
G7 X Mark II
ISO 125
F4 (F10.9 equiv)
1/1250th

For this scene, we set both cameras on the same tripod, and exposed the scene to just barely clip the highlights of the sun's reflection on the building at center; though the exposure settings differ, both cameras received roughly the same amount of light at each of their respective base ISO values.

It's clear to see that in this sort of scene, the G1 X III exhibits less noise in the lifted shadow areas than its smaller-sensored sibling, and there are areas, particularly in the trees, where fine detail is rendered a tad better.

We should note that these sorts of bright daylight scenes (where you're not light-limited and can use base ISO), are where the G1 X III will really pull ahead of the G7 X II. In scenes with even more contrast than this, the difference will become even more apparent.

Close-range indoors

By 28mm equiv, the graph shows that both cameras sensor/lens combinations are offering the same equivalent focal length and roughly the same equivalent aperture. Which means, in principle, that they should receive the same amount of total light, when shot wide open at the same shutter speed (and whatever ISO is necessary). The only differences should stem from differences in sensor performance and lens characteristics.

G1 X Mark III
ISO 500
F3.2 (F5.2 equiv)
1/30th
G7 X Mark II
ISO 160
F2 (F5.5 equiv)
1/30th

Click through to see for yourself how each camera renders the background highlights - there is a bit of an 'onion-ring' effect from the G7 X II, though the G1 X III image looks just slightly noisier. This is indicative of a slightly less efficient sensor design compared to the backside-illuminated (BSI) unit in the G7 X II.

Low light, casual portrait

This sort of situation is usually where people expect to see the benefits of a larger sensor, but this is only true if you can give it enough light. Here's a shot from the long end of the G1X III's lens in a situation where you'd need to shoot wide-open. As can be seen from the graph at the top of the page, the G7 X II has a wider equivalent aperture at this point. Let's see what that means.

G1 X Mark III
ISO 12,800
F5.6 (F9.3 equiv)
1/60th
G7 X Mark II
ISO 5000
F2.8 (F7.6 equiv)
1/60th

Both cameras were zoomed to ~72mm, and I kept my shutter speed at 1/60 sec to account for any slight subject movement. Because the G1 X III's lens only opens to F5.6 at its maximum zoom, the ISO value hit the maximum value I'd chosen of 12800, while the G7 X II, at F2.8, called for an ISO value of 5000.

After checking the difference in exposure value for both cameras, the G1 X III required an additional 0.64 EV boost in Adobe Camera Raw, which is effectively like shooting at ISO 20000. So in this situation, the G7 X II's image is cleaner and offers slightly blurrier out-of-focus highlights in the background. Overall, the advantage of the larger sensor is essentially canceled out by the slower lens.

Maximum zoom portrait

So that's how the two cameras compare within the range that both lenses cover. But now, let's look at how the G7 X II at 100mm of equivalent reach compares to the G1 X III at its maximum of 72mm.

G1 X Mark III
ISO 400
F5.6 (F9.3 equiv)
1/125th
G7 X Mark II
ISO 125
F2.8 (F7.6 equiv)
1/125th

Here, you can see just how much of a difference the extra reach on the G7 X II's lens can make. Both images were taken from the same location moments apart, with each lens shot wide open.

To us, this really exemplifies that, though the 24-72mm focal range of the G1 X III is indeed quite versatile, the extra zoom range on the G7 X II can really be a big advantage for those looking for a small camera for casual portraiture. Of course, if you're into artificial lighting, the G1 X III's hot-shoe will allow you far more creative options than the G7 X II, which has a built-in flash and no other flash synchronization options.

Takeaways

This comparison is, of course, purposely limited to the image quality impact of the lenses and sensors on these two cameras. There's a lot of other features that separate the G1 X III and G7 X II, including that the former offers better dynamic range, weather sealing, an electronic viewfinder, a flash hot shoe, a fully articulating screen, and Dual Pixel AF (and, disappointingly, Canon hasn't updated its G5 X model, which would have been a closer match to the G7 X II in the first place).

If all those other aspects of the G1 X III are worth the price premium to you, by all means, pick up a G1 X III. It's a lovely camera, with excellent handling and is capable of great image quality under a wide variety of scenarios.

Here comes the 'but' though... if you're looking for (in our opinion) a better value, or you're looking for an even smaller camera, or you shoot in low or marginal light more often than bright daylight, the G7 X II is almost certain to be a better fit, at a cheaper price. And this is why we just weren't blown away by the G1 X III in our review; you greatly reduce the benefits of such a large and expensive sensor if you restrict its access to light to squeeze it into such a compact body.

But what about you? Have you used one or both of these cameras? Let us know what you think of our comparisons in the comments.