Canon G7 X Mark III vs Sony A7S

The Canon PowerShot G7 X Mark III and the Sony Alpha A7S are two digital cameras that were announced, respectively, in July 2019 and April 2014. The G7X Mark III is a fixed lens compact, while the A7S is a mirrorless interchangeable lens camera. The cameras are based on an one-inch (G7X Mark III) and a full frame (A7S) sensor. The Canon has a resolution of 20 megapixels, whereas the Sony provides 12 MP.

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

Headline Specifications

Canon G7 X Mark III		Sony A7S
Fixed lens compact camera		Mirrorless system camera
24-100mm f/1.8-2.8		Sony E mount lenses
20 MP – 1" sensor		12 MP – Full Frame sensor
4K/30p Video		1080/60p Video
ISO 125-12,800 (125 - 25,600)		ISO 100-102,400 (50 - 409,600)
No viewfinder, LCD framing		Electronic viewfinder (2400k dots)
3.0" LCD – 1040k dots		3.0" LCD – 921k dots
Tilting touchscreen		Tilting screen (no touchscreen)
30 shutter flaps per second		5 shutter flaps per second
not weather sealed		Weathersealed body
235 shots per battery charge		380 shots per battery charge
105 x 61 x 41 mm, 304 g		127 x 94 x 48 mm, 489 g

Check G7X Mark III price at
amazon.com
Check A7S offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Canon PowerShot G7 X Mark III and the Sony Alpha A7S? 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 physical size and weight of the Canon G7 X Mark III and the Sony A7S are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth measures are rounded to the nearest millimeter.

The G7X Mark III can be obtained in two different colors (black, silver), while the A7S is only available in black.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7S is considerably larger (86 percent) than the Canon G7 X Mark III. It is noteworthy in this context that the A7S is splash and dust-proof, while the G7X Mark III does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the G7X Mark III has a lens built in, whereas the A7S 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 and their specifications in the Sony FE Lens Catalog.

Concerning battery life, the G7X Mark III gets 235 shots out of its Canon NB-13L battery, while the A7S can take 380 images on a single charge of its Sony NP-FW50 power pack. The battery packs of both cameras can be charged via USB, 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. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.

Body Specifications

#		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price (USD)	Street Price
1.		Canon G7 X Mark III	105 mm	61 mm	41 mm	304 g	235	n	Jul 2019	749	amazon.com
2.		Sony A7S	127 mm	94 mm	48 mm	489 g	380	Y	Apr 2014	2,499	ebay.com
3.		Canon G5 X Mark II	111 mm	61 mm	46 mm	340 g	230	n	Jul 2019	899	ebay.com
4.		Canon SX740	110 mm	64 mm	40 mm	299 g	265	n	Jul 2018	399	amazon.com
5.		Canon G7 X Mark II	106 mm	61 mm	42 mm	319 g	265	n	Feb 2016	699	ebay.com
6.		Canon G5 X	112 mm	76 mm	44 mm	353 g	210	n	Oct 2015	799	ebay.com
7.		Canon G7 X	103 mm	60 mm	40 mm	304 g	210	n	Sep 2014	699	ebay.com
8.		Leica C-LUX	113 mm	67 mm	46 mm	340 g	370	n	Jun 2018	1,049	ebay.com
9.		Nikon Df	144 mm	110 mm	67 mm	760 g	1400	Y	Nov 2013	2,749	ebay.com
10.		Panasonic FZ1000 II	136 mm	97 mm	131 mm	810 g	350	n	Feb 2019	899	amazon.com
11.		Panasonic ZS200	111 mm	65 mm	45 mm	340 g	370	n	Feb 2018	799	amazon.com
12.		Sony ZV-E1	121 mm	72 mm	54 mm	483 g	570	Y	Mar 2023	2,199	amazon.com
13.		Sony ZV-1	105 mm	60 mm	44 mm	294 g	260	n	May 2020	799	ebay.com
14.		Sony RX100 VI	102 mm	58 mm	43 mm	301 g	240	n	Jun 2018	1,199	ebay.com
15.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
16.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	1,699	ebay.com
17.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	2,299	ebay.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 naturally be influenced heavily by the price. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The G7X Mark III was launched at a lower price than the A7S, 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 imaging sensor is a crucial determinant of image quality. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixels in a sensor of the same technological generation. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better isolate a subject from the background. On the downside, larger sensors tend to be associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Canon G7 X Mark III features an one-inch sensor and the Sony A7S a full frame sensor. The sensor area in the A7S is 638 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.7 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Despite having a smaller sensor, the Canon G7 X Mark III offers a higher resolution of 20 megapixels, compared with 12 MP of the Sony A7S. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 2.41μm versus 8.45μm for the A7S). However, it should be noted that the G7X Mark III is much more recent (by 5 years and 3 months) than the A7S, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently.

The resolution advantage of the Canon G7 X Mark III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the G7X Mark III for good quality output (200 dots per inch) amounts to 27.4 x 18.2 inches or 69.5 x 46.3 cm, for very good quality (250 dpi) 21.9 x 14.6 inches or 55.6 x 37.1 cm, and for excellent quality (300 dpi) 18.2 x 12.2 inches or 46.3 x 30.9 cm. The corresponding values for the Sony A7S are 21.2 x 14.2 inches or 53.8 x 36 cm for good quality, 17 x 11.3 inches or 43.1 x 28.8 cm for very good quality, and 14.1 x 9.4 inches or 35.9 x 24 cm for excellent quality prints.

The Canon PowerShot G7 X Mark III has a native sensitivity range from ISO 125 to ISO 12800, which can be extended to ISO 125-25600. The corresponding ISO settings for the Sony Alpha A7S are ISO 100 to ISO 102400, with the possibility to increase the ISO range to 50-409600.

In terms of underlying technology, the G7X Mark III is build around a BSI-CMOS sensor, while the A7S uses a 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.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. This service is based on lab testing and assigns an overall score to each camera sensor, as well as ratings for dynamic range ("DXO Landscape"), color depth ("DXO Portrait"), and low-light sensitivity ("DXO Sports"). The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

Sensor Characteristics

#		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Canon G7 X Mark III	1-inch	20.0	5472	3648	4K/30p	22.2	12.4	583	65
2.		Sony A7S	Full Frame	12.0	4240	2832	1080/60p	23.9	13.2	3702	87
3.		Canon G5 X Mark II	1-inch	20.0	5472	3648	4K/30p	22.2	12.4	583	65
4.		Canon SX740	1/2.3	20.2	5184	3888	4K/30p	20.6	12.1	1050	51
5.		Canon G7 X Mark II	1-inch	20.0	5472	3648	1080/60p	21.8	11.9	260	62
6.		Canon G5 X	1-inch	20.0	5472	3648	1080/60p	21.4	12.3	471	62
7.		Canon G7 X	1-inch	20.0	5472	3648	1080/60p	23.0	12.7	556	71
8.		Leica C-LUX	1-inch	20.0	5472	3648	4K/30p	22.1	12.3	481	64
9.		Nikon Df	Full Frame	16.2	4928	3280	none	24.6	13.1	3279	89
10.		Panasonic FZ1000 II	1-inch	20.0	5472	3648	4K/30p	22.1	12.4	546	65
11.		Panasonic ZS200	1-inch	20.0	5472	3648	4K/30p	22.0	12.2	449	64
12.		Sony ZV-E1	Full Frame	12.0	4240	2832	4K/60p	25.4	14.6	3181	96
13.		Sony ZV-1	1-inch	20.0	5472	3648	4K/30p	22.2	12.6	669	66
14.		Sony RX100 VI	1-inch	20.0	5472	3648	4K/30p	22.1	12.3	478	64
15.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
16.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90
17.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the G7X Mark III provides a higher video resolution than the A7S. It can shoot video footage at 4K/30p, while the Sony is limited to 1080/60p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A7S has an electronic viewfinder (2400k dots), which can be very helpful when shooting in bright sunlight. In contrast, the G7X Mark III relies on live view and the rear LCD for framing. The following table reports on some other key feature differences and similarities of the Canon G7 X Mark III, the Sony A7S, and comparable cameras.

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 G7 X Mark III	none	n	3.0 / 1040	tilting	Y	1/2000s	30/s	Y	Y
2.		Sony A7S	2400	n	3.0 / 921	tilting	n	1/8000s	5.0/s	n	n
3.		Canon G5 X Mark II	2360	n	3.0 / 1040	tilting	Y	1/2000s	30/s	Y	Y
4.		Canon SX740	none	n	3.0 / 922	tilting	n	1/3200s	10.0/s	Y	Y
5.		Canon G7 X Mark II	none	n	3.0 / 1040	tilting	Y	1/2000s	8.0/s	Y	Y
6.		Canon G5 X	2360	n	3.0 / 1040	swivel	Y	1/2000s	5.9/s	Y	Y
7.		Canon G7 X	none	n	3.0 / 1040	tilting	Y	1/2000s	6.5/s	Y	Y
8.		Leica C-LUX	2330	n	3.0 / 1240	fixed	Y	1/2000s	10.0/s	Y	Y
9.		Nikon Df	optical	Y	3.2 / 921	fixed	n	1/4000s	5.5/s	n	n
10.		Panasonic FZ1000 II	2360	n	3.0 / 1240	swivel	Y	1/4000s	12.0/s	Y	Y
11.		Panasonic ZS200	2330	n	3.0 / 1240	fixed	Y	1/2000s	10.0/s	Y	Y
12.		Sony ZV-E1	none	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
13.		Sony ZV-1	none	n	3.0 / 922	swivel	Y	1/2000s	24.0/s	n	n
14.		Sony RX100 VI	2359	n	3.0 / 1229	tilting	Y	1/2000s	24.0/s	Y	Y
15.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
16.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
17.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
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 G7X Mark III has one, while the A7S does not. While the built-in flash of the G7X Mark III 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, both cameras under consideration feature an 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 Canon G7 X Mark III has an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.

The G7X Mark III writes its imaging data to SDXC cards, while the A7S uses SDXC or Memory Stick PRO Duo cards. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.

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 G7 X Mark III and Sony Alpha A7S 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 G7 X Mark III	-	stereo / mono	Y	-	micro	3.1	Y	-	Y
2.		Sony A7S	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
3.		Canon G5 X Mark II	-	stereo / mono	-	-	micro	3.1	Y	-	Y
4.		Canon SX740	-	stereo / mono	-	-	micro	2.0	Y	-	Y
5.		Canon G7 X Mark II	-	stereo / mono	-	-	micro	2.0	Y	Y	-
6.		Canon G5 X	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
7.		Canon G7 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
8.		Leica C-LUX	-	stereo / mono	-	-	micro	2.0	Y	-	-
9.		Nikon Df	Y	- / -	-	-	mini	2.0	-	-	-
10.		Panasonic FZ1000 II	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
11.		Panasonic ZS200	-	stereo / mono	-	-	micro	2.0	Y	-	Y
12.		Sony ZV-E1	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
13.		Sony ZV-1	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
14.		Sony RX100 VI	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
15.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony A7	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-

It is notable that the A7S has a hotshoe, which makes it possible to easily attach optional accessories, such as an external flash gun. The G7X Mark III does not feature such an accessory-socket.

The G7X Mark III is a recent model that features in the current product line-up of Canon. In contrast, the A7S has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the A7S was succeeded by the Sony A7S II. Further information on the features and operation of the G7X Mark III and A7S can be found, respectively, in the Canon G7 X Mark III Manual (free pdf) or the online Sony A7S Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Canon G7 X Mark III and the Sony A7S? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Canon PowerShot G7 X Mark III:

• More detail: Offers more megapixels (20 vs 12MP) with a 29% higher linear resolution.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• More detailed LCD: Has a higher resolution rear screen (1040k vs 921k dots).
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster burst: Shoots at higher frequency (30 vs 5 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Ready to shoot: Has a lens built-in, whereas the A7S requires a separate lens.
• More compact: Is smaller (105x61mm vs 127x94mm) and thus needs less room in the bag.
• Less heavy: Is lighter even though it comes with a built-in lens (unlike the A7S).
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More modern: Reflects 5 years and 3 months of technical progress since the A7S launch.

Arguments in favor of the Sony Alpha A7S:

• Better sound control: Has a headphone port that enables audio monitoring while recording.
• Easier framing: Has an electronic viewfinder for image composition and settings control.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/2000s) to freeze action.
• More flexible: Takes interchangeable lenses and can thus be used with specialty optics.
• Longer lasting: Gets more shots (380 versus 235) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More heavily discounted: Has been around for much longer (launched in April 2014).

If the count of individual advantages (bullet points above) is taken as a guide, the G7X Mark III is the clear winner of the match-up (16 : 9 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision on a new camera. 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 G7 X Mark III and the Sony A7S 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 G7X Mark III or the A7S. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.

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 (USD)	Street Price
1.		Canon G7 X Mark III	..	+ +	4/5	81/100	4/5	..	Jul 2019	749	amazon.com
2.		Sony A7S	4/5	..	..	86/100	4.5/5	5/5	Apr 2014	2,499	ebay.com
3.		Canon G5 X Mark II	4/5	+	4/5	82/100	..	4/5	Jul 2019	899	ebay.com
4.		Canon SX740	..	+	3.5/5	..	4/5	4/5	Jul 2018	399	amazon.com
5.		Canon G7 X Mark II	4.5/5	+ +	..	81/100	4.5/5	4.5/5	Feb 2016	699	ebay.com
6.		Canon G5 X	5/5	+ +	..	78/100	4.5/5	4.5/5	Oct 2015	799	ebay.com
7.		Canon G7 X	4/5	+ +	..	77/100	4.5/5	4.5/5	Sep 2014	699	ebay.com
8.		Leica C-LUX	..	..	3.5/5	..	4.5/5	4/5	Jun 2018	1,049	ebay.com
9.		Nikon Df	4/5	..	..	81/100	4/5	4/5	Nov 2013	2,749	ebay.com
10.		Panasonic FZ1000 II	..	..	..	83/100	4.5/5	4.5/5	Feb 2019	899	amazon.com
11.		Panasonic ZS200	..	+ +	4.5/5	81/100	4.5/5	4.5/5	Feb 2018	799	amazon.com
12.		Sony ZV-E1	..	+	4/5	..	..	4.5/5	Mar 2023	2,199	amazon.com
13.		Sony ZV-1	4/5	+	4/5	85/100	4/5	4.5/5	May 2020	799	ebay.com
14.		Sony RX100 VI	4.5/5	+ +	..	83/100	4/5	4.5/5	Jun 2018	1,199	ebay.com
15.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
16.		Sony A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	1,699	ebay.com
17.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	2,299	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. 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.

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Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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