Canon G15 vs Sony A7S III

The Canon PowerShot G15 and the Sony Alpha 7S III are two digital cameras that were revealed to the public, respectively, in September 2012 and July 2020. The G15 is a fixed lens compact, while the A7S III is a mirrorless interchangeable lens camera. The cameras are based on a 1/1.7-inch (G15) and a full frame (A7S III) sensor. Both cameras offer a resolution of 12 megapixels.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Canon G15		Sony A7S III
Fixed lens compact camera		Mirrorless system camera
28-140mm f/1.8-2.8		Sony E mount lenses
12 MP – 1/1.7" sensor		12 MP – Full Frame sensor
1080/24p Video		4K/120p Video
ISO 80-12,800		ISO 80-102,400 (40 - 409,600)
Optical viewfinder		Electronic viewfinder (9440k dots)
3.0" LCD – 922k dots		3.0" LCD – 1440k dots
Fixed screen (not touch-sensitive)		Swivel touchscreen
2.1 shutter flaps per second		10 shutter flaps per second
Lens-based stabilization		In-body stabilization
not weather sealed		Weathersealed body
350 shots per battery charge		600 shots per battery charge
107 x 76 x 40 mm, 352 g		127 x 97 x 81 mm, 699 g

Check G15 offers at
ebay.com
Check A7S III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Canon PowerShot G15 and the Sony Alpha 7S III? Which one should you buy? Read on to find out how these two cameras compare with respect to their body size, their imaging sensors, their shooting features, their input-output connections, and their reception by expert reviewers.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Canon G15 and the Sony A7S III. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side are shown. All width, height and depth dimensions are rounded to the nearest millimeter.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7S III is considerably larger (51 percent) than the Canon G15. It is noteworthy in this context that the A7S III is splash and dust-proof, while the G15 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the G15 has a lens built in, whereas the A7S III is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup. You can compare the optics available for the A7S III and their specifications in the Sony FE Lens Catalog.

Concerning battery life, the G15 gets 350 shots out of its Canon NB-10L battery, while the A7S III can take 600 images on a single charge of its Sony NP-FZ100 power pack. The power pack in the A7S III can be charged via the USB port, which can be very convenient when travelling.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. In case you want to display and compare another camera duo, you can use the CAM-parator app to select your camera combination among a large number of options.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price	Street Price
1.		Canon G15	107 mm	76 mm	40 mm	352 g	350	n	Sep 2012	US$ 499	ebay.com
2.		Sony A7S III	127 mm	97 mm	81 mm	699 g	600	Y	Jul 2020	US$ 3 499	amazon.com
3.		Canon G12	112 mm	76 mm	48 mm	401 g	370	n	Sep 2010	US$ 499	ebay.com
4.		Canon G16	109 mm	76 mm	40 mm	356 g	360	n	Aug 2013	US$ 549	ebay.com
5.		Canon S120	100 mm	59 mm	29 mm	217 g	230	n	Aug 2013	US$ 449	ebay.com
6.		Canon SX50	123 mm	87 mm	106 mm	595 g	315	n	Sep 2012	US$ 429	ebay.com
7.		Canon SX60	128 mm	93 mm	114 mm	650 g	340	n	Sep 2014	US$ 549	ebay.com
8.		Fujifilm X10	117 mm	70 mm	57 mm	350 g	270	n	Sep 2011	US$ 599	ebay.com
9.		Fujifilm X20	117 mm	70 mm	57 mm	353 g	270	n	Jan 2013	US$ 599	ebay.com
10.		Nikon P7800	119 mm	78 mm	50 mm	399 g	350	n	Sep 2013	US$ 549	ebay.com
11.		Panasonic FZ150	124 mm	82 mm	92 mm	528 g	410	n	Aug 2011	US$ 499	ebay.com
12.		Panasonic LX7	111 mm	68 mm	46 mm	298 g	330	n	Jul 2012	US$ 499	ebay.com
13.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	US$ 3 199	ebay.com
14.		Sony A7R IV	129 mm	96 mm	78 mm	665 g	670	Y	Jul 2019	US$ 3 499	ebay.com
15.		Sony A7R IVA	129 mm	96 mm	78 mm	665 g	670	Y	Apr 2021	US$ 3 499	amazon.com
16.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	US$ 2 999	ebay.com
17.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	US$ 4 499	amazon.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
Convert to Imperial

Any camera decision will obviously take relative prices into account. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The G15 was launched at a lower price than the A7S III, despite having a lens built in. Usually, retail prices stay at first close to the launch price, but after several months, discounts become available. Later in the product cycle and, in particular, when the replacement model is about to appear, further discounting and stock clearance sales often push the camera price considerably down.

Sensor comparison

The size of the sensor inside a digital camera is one of the key determinants of image quality. A large sensor will generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have richer color-depth than smaller pixels in a sensor of the same technological generation. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its background. On the downside, larger sensors are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Canon G15 features a 1/1.7-inch sensor and the Sony A7S III a full frame sensor. The sensor area in the A7S III is 1870 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 4.6 and 1.0. The sensor in the G15 has a native 4:3 aspect ratio, while the one in the A7S III offers a 3:2 aspect.

Even though the A7S III has a larger sensor, both cameras offer the same resolution of 12 megapixels. This implies that the A7S III has a lower pixel density and larger individual pixels (with a pixel pitch of 8.40μm versus 1.89μm for the G15), which gives it a potential advantage in terms of light gathering capacity. In addition, the A7S III is much more recent (by 7 years and 10 months) than the G15, and its sensor will have benefitted from technological advances during this time.

The A7S III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Canon PowerShot G15 has a native sensitivity range from ISO 80 to ISO 12800. The corresponding ISO settings for the Sony Alpha 7S III are ISO 80 to ISO 102400, with the possibility to increase the ISO range to 40-409600.

In terms of underlying technology, the G15 is build around a CMOS sensor, while the A7S III uses a BSI-CMOS imager. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. This service assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. Of the two cameras under consideration, the A7S III offers substantially better image quality than the G15 (overall score 40 points higher). The advantage is based on 3.8 bits higher color depth, 2.4 EV in additional dynamic range, and 3.9 stops in additional low light sensitivity. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Canon G15	1/1.7	12.0	4000	3000	1080/24p	19.9	11.5	165	46
2.		Sony A7S III	Full Frame	12.0	4240	2832	4K/120p	23.7	13.9	2520	86
3.		Canon G12	1/1.7	10.0	3648	2736	720/24p	20.4	11.2	161	47
4.		Canon G16	1/1.7	12.0	4000	3000	1080/60p	21.0	11.7	230	54
5.		Canon S120	1/1.7	12.0	4000	3000	1080/60p	21.3	11.9	246	56
6.		Canon SX50	1/2.3	12.0	4000	3000	1080/24p	20.3	11.2	179	47
7.		Canon SX60	1/2.3	14.2	4608	3072	1080/60p	19.2	10.8	127	39
8.		Fujifilm X10	2/3	12.0	4000	3000	1080/30p	20.5	11.3	245	50
9.		Fujifilm X20	2/3	12.0	4000	3000	1080/60p	20.1	10.9	-462	46
10.		Nikon P7800	1/1.7	12.0	4000	3000	1080/30p	21.2	11.7	200	54
11.		Panasonic FZ150	1/2.3	12.0	4000	3000	1080/60p	19.4	10.9	132	40
12.		Panasonic LX7	1/1.7	10.0	3648	2736	1080/60p	20.7	11.7	147	50
13.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
14.		Sony A7R IV	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
15.		Sony A7R IVA	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
16.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
17.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A7S III provides a better video resolution than the G15. It can shoot movie footage at 4K/120p, while the Canon is limited to 1080/24p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A7S III has an electronic viewfinder (9440k dots), while the G15 has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The adjacent table lists some of the other core features of the Canon G15 and Sony A7S III along with similar information for a selection of comparators.

Core Features

		Camera Model	Viewfinder (Type or 000 dots)	Control Panel (yes/no)	LCD Specifications (inch/000 dots)	LCD Attach- ment	Touch Screen (yes/no)	Max Shutter Speed *	Max Shutter Flaps *	Built-in Flash (yes/no)	Built-in Image Stab
1.		Canon G15	optical	n	3.0 / 922	fixed	n	1/4000s	2.1/s	Y	Y
2.		Sony A7S III	9440	n	3.0 / 1440	swivel	Y	1/8000s	10.0/s	n	Y
3.		Canon G12	optical	n	2.8 / 461	swivel	n	1/4000s	1.1/s	Y	Y
4.		Canon G16	optical	n	3.0 / 922	fixed	n	1/4000s	2.2/s	Y	Y
5.		Canon S120	none	n	3.0 / 922	fixed	Y	1/2000s	12.1/s	Y	Y
6.		Canon SX50	202	n	3.0 / 461	swivel	n	1/2000s	2.2/s	Y	Y
7.		Canon SX60	922	n	3.0 / 922	swivel	n	1/2000s	6.4/s	Y	Y
8.		Fujifilm X10	optical	n	2.8 / 460	fixed	n	1/4000s	10.0/s	Y	Y
9.		Fujifilm X20	optical	n	2.8 / 460	fixed	n	1/4000s	12.0/s	Y	Y
10.		Nikon P7800	921	n	3.0 / 921	swivel	n	1/4000s	8.0/s	Y	Y
11.		Panasonic FZ150	202	n	3.0 / 460	swivel	n	1/2000s	12.0/s	Y	Y
12.		Panasonic LX7	optional	n	3.0 / 920	fixed	n	1/4000s	11.0/s	Y	Y
13.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
14.		Sony A7R IV	5760	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
15.		Sony A7R IVA	5760	n	3.0 / 2340	tilting	Y	1/8000s	10.0/s	n	Y
16.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
17.		Sony A9 II	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One difference between the cameras concerns the presence of an on-board flash. The G15 has one, while the A7S III does not. While the built-in flash of the G15 is not very powerful, it can at times be useful as a fill-in light.

The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the A7S III is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).

The G15 writes its imaging data to SDXC cards, while the A7S III uses CFexpress (type A) or SDXC cards. The A7S III features dual card slots, which can be very useful in case a memory card fails. In contrast, the G15 only has one slot. The A7S III supports UHS-II cards (on both slots), while the G15 cannot take advantage of Ultra High Speed SD cards.

Connectivity comparison

For some imaging applications, the extent to which a camera can communicate with its environment can be an important aspect in the camera decision process. The table below provides an overview of the connectivity of the Canon PowerShot G15 and Sony Alpha 7S III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

Input-Output Connections

		Camera Model	Hotshoe Port	Internal Mic / Speaker	Microphone Port	Headphone Port	HDMI Port	USB Port	WiFi Support	NFC Support	Bluetooth Support
1.		Canon G15	Y	stereo / mono	-	-	mini	2.0	-	-	-
2.		Sony A7S III	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
3.		Canon G12	Y	stereo / mono	-	-	mini	2.0	-	-	-
4.		Canon G16	Y	stereo / mono	-	-	mini	2.0	Y	-	-
5.		Canon S120	-	stereo / mono	-	-	mini	2.0	Y	-	-
6.		Canon SX50	Y	stereo / mono	-	-	mini	2.0	-	-	-
7.		Canon SX60	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
8.		Fujifilm X10	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Fujifilm X20	Y	stereo / mono	-	-	micro	2.0	-	-	-
10.		Nikon P7800	Y	stereo / mono	Y	-	mini	2.0	-	-	-
11.		Panasonic FZ150	Y	stereo / -	-	-	mini	2.0	-	-	-
12.		Panasonic LX7	Y	stereo / mono	-	-	mini	2.0	-	-	-
13.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
14.		Sony A7R IV	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
15.		Sony A7R IVA	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
16.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y

It is notable that the A7S III offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the G15 does not provide wifi capability.

The A7S III is a recent model that features in the current product line-up of Sony. In contrast, the G15 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the G15 was succeeded by the Canon G16. Further information on the features and operation of the G15 and A7S III can be found, respectively, in the Canon G15 Manual (free pdf) or the online Sony A7S III Manual.

Review summary

So what conclusions can be drawn? Is the Canon G15 better than the Sony A7S III or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Canon PowerShot G15:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Ready to shoot: Has a lens built-in, whereas the A7S III requires a separate lens.
• More compact: Is smaller (107x76mm vs 127x97mm) and thus needs less room in the bag.
• Less heavy: Is lighter even though it comes with a built-in lens (unlike the A7S III).
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More heavily discounted: Has been available for much longer (launched in September 2012).

Advantages of the Sony Alpha 7S III:

• Better image quality: Scores substantially higher (40 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (3.8 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.4 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (3.9 stops ISO advantage).
• Better video: Provides higher definition movie capture (4K/120p vs 1080/24p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Better sound: Can connect to an external microphone for higher quality sound recording.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• More framing info: Has an electronic viewfinder that displays shooting data.
• More detailed LCD: Has a higher resolution rear screen (1440k vs 922k dots).
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (10 vs 2.1 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• More flexible: Takes interchangeable lenses and can thus be used with specialty optics.
• Longer lasting: Gets more shots (600 versus 350) out of a single battery charge.
• Easier travel charging: Can be conveniently charged via its USB port.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• Faster buffer clearing: Supports Ultra High Speed (UHS-II) SDXC cards on both slots.
• More modern: Reflects 7 years and 10 months of technical progress since the G15 launch.

If the number of relative strengths (bullet points above) is taken as a guide, the A7S III is the clear winner of the contest (27 : 7 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. A professional wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports shooter. Hence, the decision which camera is best and worth buying is often a very personal one.

How about other alternatives? Do the specifications of the Canon G15 and the Sony A7S III place the cameras among the top in their class? Find out in the latest Best Travel-Zoom Camera and Best Mirrorless Interchangeable Lens Camera listings whether the two cameras rank among the cream of the crop.

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the G15 or the A7S III. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable.

Expert reviews

This is why hands-on reviews by experts are important. The table below provides a synthesis of the camera assessments of some of the best known photo-gear review sites (amateurphotographer [AP], cameralabs [CL], digitalcameraworld [DCW], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.

Expert Camera Reviews

		Camera   Model	AP   score	CL   score	DCW   score	DPR   score	EPZ   score	PB   score	Camera Launch	Launch Price	Street Price
1.		Canon G15	4/5	+	..	76/100	4.5/5	4.5/5	Sep 2012	US$ 499	ebay.com
2.		Sony A7S III	4.5/5	+ +	5/5	91/100	4.5/5	5/5	Jul 2020	US$ 3 499	amazon.com
3.		Canon G12	4/5	+	..	73/100	4.5/5	4.5/5	Sep 2010	US$ 499	ebay.com
4.		Canon G16	4/5	+	..	..	4.5/5	4.5/5	Aug 2013	US$ 549	ebay.com
5.		Canon S120	..	+ +	..	..	4.5/5	4.5/5	Aug 2013	US$ 449	ebay.com
6.		Canon SX50	3/5	+ +	..	72/100	4.5/5	4.5/5	Sep 2012	US$ 429	ebay.com
7.		Canon SX60	3/5	+ +	..	75/100	4/5	4.5/5	Sep 2014	US$ 549	ebay.com
8.		Fujifilm X10	..	..	..	76/100	4/5	4.5/5	Sep 2011	US$ 599	ebay.com
9.		Fujifilm X20	4/5	+ +	..	77/100	4.5/5	5/5	Jan 2013	US$ 599	ebay.com
10.		Nikon P7800	3/5	..	..	..	4/5	4.5/5	Sep 2013	US$ 549	ebay.com
11.		Panasonic FZ150	3/5	+ +	..	76/100	4/5	4.5/5	Aug 2011	US$ 499	ebay.com
12.		Panasonic LX7	3/5	+ +	..	75/100	4/5	4.5/5	Jul 2012	US$ 499	ebay.com
13.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	US$ 3 199	ebay.com
14.		Sony A7R IV	5/5	+	4.5/5	91/100	4.5/5	5/5	Jul 2019	US$ 3 499	ebay.com
15.		Sony A7R IVA	5/5	+	4.5/5	91/100	4.5/5	5/5	Apr 2021	US$ 3 499	amazon.com
16.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	US$ 2 999	ebay.com
17.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	US$ 4 499	amazon.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Check G15 offers at
ebay.com
Check A7S III price at
amazon.com

Other camera comparisons

Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

~

Check G15 offers at
ebay.com
Check A7S III price at
amazon.com

Did you notice an error on this page? If so, please get in touch, so that we can correct the information.