Sony A7 III vs Canon M3

The Sony Alpha A7 III and the Canon EOS M3 are two digital cameras that were announced, respectively, in February 2018 and February 2015. Both the A7 III and the M3 are mirrorless interchangeable lens cameras that are based on a full frame (A7 III) and an APS-C (M3) sensor. Both cameras offer a resolution of 24 megapixels.

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

Headline Specifications

Sony A7 III		Canon M3
Mirrorless system camera		Mirrorless system camera
Sony E mount lenses		Canon EF-M mount lenses
24 MP – Full Frame sensor		24 MP – APS-C sensor
4K/30p Video		1080/30p Video
ISO 100-51,200 (50 - 204,800)		ISO 100-12,800 (100 - 25,600)
Electronic viewfinder (2359k dots)		Viewfinder optional
3.0" LCD – 922k dots		3.0" LCD – 1040k dots
Tilting touchscreen		Tilting touchscreen
10 shutter flaps per second		4.2 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		not weather sealed
610 shots per battery charge		250 shots per battery charge
127 x 96 x 74 mm, 650 g		111 x 68 x 44 mm, 366 g

Check A7 III price at
amazon.com
Check M3 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A7 III and the Canon EOS M3? 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

An illustration of the physical size and weight of the Sony A7 III and the Canon M3 is provided in the side-by-side display below. 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 size dimensions are rounded to the nearest millimeter.

The M3 can be obtained in two different colors (black, white), while the A7 III 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 Canon M3 is considerably smaller (38 percent) than the Sony A7 III. Moreover, the M3 is substantially lighter (44 percent) than the A7 III. It is worth mentioning in this context that the A7 III is splash and dust resistant, while the M3 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete since they do not consider the interchangeable lenses that both of these cameras require. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

Concerning battery life, the A7 III gets 610 shots out of its Sony NP-FZ100 battery, while the M3 can take 250 images on a single charge of its Canon LP-E17 power pack. The power pack in the A7 III can be charged via the USB port, so that it is not always necessary to take the battery charger along when travelling.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	1,999	amazon.com
2.		Canon M3	111 mm	68 mm	44 mm	366 g	250	n	Feb 2015	679	ebay.com
3.		Canon 6D Mark II	144 mm	111 mm	75 mm	765 g	1200	Y	Jun 2017	1,999	amazon.com
4.		Canon M5	116 mm	89 mm	61 mm	427 g	295	n	Sep 2016	979	ebay.com
5.		Canon M6	112 mm	68 mm	45 mm	390 g	295	n	Feb 2017	779	ebay.com
6.		Canon M100	108 mm	67 mm	35 mm	302 g	295	n	Aug 2017	499	ebay.com
7.		Canon T6i	132 mm	101 mm	78 mm	555 g	440	n	Feb 2015	749	ebay.com
8.		Canon T6s	132 mm	101 mm	78 mm	565 g	440	n	Feb 2015	649	ebay.com
9.		Nikon Z6	134 mm	101 mm	67 mm	675 g	310	Y	Aug 2018	1,999	ebay.com
10.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999	ebay.com
11.		Sony A7 IV	131 mm	96 mm	80 mm	659 g	580	Y	Oct 2021	2,499	amazon.com
12.		Sony A7C	124 mm	71 mm	60 mm	509 g	740	Y	Sep 2020	1,799	amazon.com
13.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	3,199	ebay.com
14.		Sony A7R IIIA	127 mm	96 mm	74 mm	650 g	650	Y	Apr 2021	3,199	amazon.com
15.		Sony A7R IV	129 mm	96 mm	78 mm	665 g	670	Y	Jul 2019	3,499	ebay.com
16.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
17.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	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 retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. The M3 was launched at a markedly lower price (by 66 percent) than the A7 III, which puts it into a different market segment. 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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. 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 tend to be more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A7 III features a full frame sensor and the Canon M3 an APS-C sensor. The sensor area in the M3 is 61 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 1.6. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Even though the A7 III has a larger sensor, both cameras offer the same resolution of 24 megapixels. This implies that the A7 III has a lower pixel density and larger individual pixels (with a pixel pitch of 5.94μm versus 3.72μm for the M3), which gives it a potential advantage in terms of light gathering capacity. In addition, the A7 III is much more recent (by 3 years) than the M3, and its sensor will have benefitted from technological advances during this time.

The Sony Alpha A7 III has a native sensitivity range from ISO 100 to ISO 51200, which can be extended to ISO 50-204800. The corresponding ISO settings for the Canon EOS M3 are ISO 100 to ISO 12800, with the possibility to increase the ISO range to 100-25600.

In terms of underlying technology, the A7 III is build around a BSI-CMOS sensor, while the M3 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 determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). Of the two cameras under review, the A7 III provides substantially higher image quality than the M3, with an overall score that is 24 points higher. This advantage is based on 2.2 bits higher color depth, 2.9 EV in additional dynamic range, and 1.7 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.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
2.		Canon M3	APS-C	24.0	6000	4000	1080/30p	22.8	11.8	1169	72
3.		Canon 6D Mark II	Full Frame	26.0	6240	4160	1080/60p	24.4	11.9	2862	85
4.		Canon M5	APS-C	24.0	6000	4000	1080/60p	23.4	12.4	1262	77
5.		Canon M6	APS-C	24.0	6000	4000	1080/60p	23.4	12.6	1317	78
6.		Canon M100	APS-C	24.0	6000	4000	1080/60p	23.5	12.9	1272	78
7.		Canon T6i	APS-C	24.0	6000	4000	1080/30p	22.7	12.0	919	71
8.		Canon T6s	APS-C	24.0	6000	4000	1080/30p	22.6	12.0	915	70
9.		Nikon Z6	Full Frame	24.3	6048	4024	4K/30p	25.3	14.3	3299	95
10.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
11.		Sony A7 IV	Full Frame	32.7	7008	4672	4K/60p	25.4	14.7	3379	97
12.		Sony A7C	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3407	95
13.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
14.		Sony A7R IIIA	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
15.		Sony A7R IV	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
16.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
17.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93

Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A7 III provides a higher video resolution than the M3. It can shoot video footage at 4K/30p, while the Canon is limited to 1080/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A7 III has an electronic viewfinder (2359k dots), which can be very helpful when shooting in bright sunlight. In contrast, the M3 relies on live view and the rear LCD for framing. That said, the M3 can be equipped with an optional viewfinder – the EVF-DC1. The adjacent table lists some of the other core features of the Sony A7 III and Canon M3 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.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
2.		Canon M3	optional	n	3.0 / 1040	tilting	Y	1/4000s	4.2/s	Y	n
3.		Canon 6D Mark II	optical	Y	3.0 / 1040	swivel	Y	1/4000s	6.5/s	n	n
4.		Canon M5	2360	n	3.2 / 1620	tilting	Y	1/4000s	9.0/s	Y	n
5.		Canon M6	optional	n	3.0 / 1040	tilting	Y	1/4000s	9.0/s	Y	n
6.		Canon M100	none	n	3.0 / 1040	tilting	Y	1/4000s	6.1/s	Y	n
7.		Canon T6i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
8.		Canon T6s	optical	Y	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
9.		Nikon Z6	3690	Y	3.2 / 2100	tilting	Y	1/8000s	12.0/s	n	Y
10.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
11.		Sony A7 IV	3686	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
12.		Sony A7C	2360	n	3.0 / 922	swivel	Y	1/4000s	10.0/s	n	Y
13.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
14.		Sony A7R IIIA	3686	n	3.0 / 2340	tilting	Y	1/8000s	10.0/s	n	Y
15.		Sony A7R IV	5760	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
16.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/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 feature that differentiates the A7 III and the M3 is in-body image stabilization (IBIS). The A7 III reduces the risk of handshake-induced blur with all attached lenses, while the M3 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

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 A7 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 Sony A7 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 A7 III writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the M3 uses SDXC cards. The A7 III features dual card slots, which can be very useful in case a memory card fails. In contrast, the M3 only has one slot. The A7 III supports UHS-II cards (on its first slot), while the M3 can use UHS-I 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 Sony Alpha A7 III and Canon EOS M3 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.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
2.		Canon M3	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
3.		Canon 6D Mark II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
4.		Canon M5	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
5.		Canon M6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
6.		Canon M100	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
7.		Canon T6i	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
8.		Canon T6s	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
9.		Nikon Z6	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
10.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
11.		Sony A7 IV	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
12.		Sony A7C	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
13.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
14.		Sony A7R IIIA	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
15.		Sony A7R IV	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
16.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
17.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y

It is notable that the A7 III has a headphone jack, which is not present on the M3 This port makes it possible to attach external headphones and monitor the quality of sound during the recording process.

The A7 III is a recent model that features in the current product line-up of Sony. In contrast, the M3 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the M3 was succeeded by the Canon M6. Further information on the features and operation of the A7 III and M3 can be found, respectively, in the Sony A7 III Manual (free pdf) or the online Canon M3 Manual.

Review summary

So how do things add up? Which of the two cameras – the Sony A7 III or the Canon M3 – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Sony Alpha A7 III:

• Better image quality: Scores substantially higher (24 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (2.2 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (2.9 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (1.7 stops ISO advantage).
• Better video: Provides higher definition movie capture (4K/30p vs 1080/30p).
• 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 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (10 vs 4.2 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Can take more shots (610 versus 250) on a single battery charge.
• Easier travel charging: Can be conveniently charged via its USB port.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
• 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 a more advanced SD data transfer standard (UHS-II vs UHS-I).
• More modern: Reflects 3 years of technical progress since the M3 launch.

Advantages of the Canon EOS M3:

• More detailed LCD: Has a higher resolution rear screen (1040k vs 922k dots).
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• More compact: Is smaller (111x68mm vs 127x96mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 284g or 44 percent) and is thus easier to take along.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• More affordable: Was introduced into a lower priced category (66 percent cheaper at launch).
• More heavily discounted: Has been around for much longer (launched in February 2015).

If the count of individual advantages (bullet points above) is taken as a guide, the A7 III is the clear winner of the match-up (20 : 7 points). However, the relevance of individual strengths will vary across photographers, so that you might want to apply your own weighing scheme to the summary points when reflecting and deciding on a new camera. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro 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 Sony A7 III and the Canon M3 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera listing whether the two cameras rank among the cream of the crop.

In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the A7 III or the M3. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.

Expert reviews

This is where reviews by experts come in. The adjacent summary-table relays the overall verdicts of several of the most popular camera 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.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	1,999	amazon.com
2.		Canon M3	4/5	o	..	75/100	4.5/5	4/5	Feb 2015	679	ebay.com
3.		Canon 6D Mark II	4/5	+	4/5	80/100	4.5/5	4/5	Jun 2017	1,999	amazon.com
4.		Canon M5	4/5	+	4/5	82/100	4/5	4/5	Sep 2016	979	ebay.com
5.		Canon M6	..	..	..	80/100	4/5	4/5	Feb 2017	779	ebay.com
6.		Canon M100	3/5	+	..	..	4/5	3.5/5	Aug 2017	499	ebay.com
7.		Canon T6i	5/5	..	..	75/100	4.5/5	4.5/5	Feb 2015	749	ebay.com
8.		Canon T6s	5/5	+	..	77/100	4.5/5	4.5/5	Feb 2015	649	ebay.com
9.		Nikon Z6	5/5	..	5/5	89/100	4.5/5	5/5	Aug 2018	1,999	ebay.com
10.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	1,999	ebay.com
11.		Sony A7 IV	5/5	+ +	4.5/5	89/100	4.5/5	4.5/5	Oct 2021	2,499	amazon.com
12.		Sony A7C	3.5/5	..	3.5/5	86/100	4/5	4/5	Sep 2020	1,799	amazon.com
13.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	3,199	ebay.com
14.		Sony A7R IIIA	..	+ +	4/5	90/100	4.5/5	5/5	Apr 2021	3,199	amazon.com
15.		Sony A7R IV	5/5	+	4.5/5	91/100	4.5/5	5/5	Jul 2019	3,499	ebay.com
16.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
17.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	4,499	amazon.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The assessments were made in relation to similar cameras of the same technological generation. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date 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

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