Canon 5D Mark III vs M6

The Canon EOS 5D Mark III and the Canon EOS M6 are two digital cameras that were announced, respectively, in March 2012 and February 2017. The 5D Mark III is a DSLR, while the M6 is a mirrorless interchangeable lens camera. The cameras are based on a full frame (5D Mark III) and an APS-C (M6) sensor. The 5D Mark III has a resolution of 22.1 megapixels, whereas the M6 provides 24 MP.

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

Headline Specifications

Canon 5D Mark III		Canon M6
Digital single lens reflex		Mirrorless system camera
Canon EF mount lenses		Canon EF-M mount lenses
22.1 MP – Full Frame sensor		24 MP – APS-C sensor
1080/30p Video		1080/60p Video
ISO 100-25,600 (50 - 102,400)		ISO 100-25,600
Optical viewfinder		Viewfinder optional
3.2" LCD – 1040k dots		3.0" LCD – 1040k dots
Fixed screen (not touch-sensitive)		Tilting touchscreen
6 shutter flaps per second		9 shutter flaps per second
Weathersealed body		not weather sealed
950 shots per battery charge		295 shots per battery charge
152 x 116 x 76 mm, 950 g		112 x 68 x 45 mm, 390 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS 5D Mark III and the Canon EOS M6? 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 Canon 5D Mark III and the Canon M6 is provided in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All size dimensions are rounded to the nearest millimeter.

The M6 can be obtained in two different colors (black, silver), while the 5D Mark 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 M6 is considerably smaller (57 percent) than the Canon 5D Mark III. Moreover, the M6 is substantially lighter (59 percent) than the 5D Mark III. It is worth mentioning in this context that the 5D Mark III is splash and dust resistant, while the M6 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 5D Mark III gets 950 shots out of its Canon LP-E6 battery, while the M6 can take 295 images on a single charge of its Canon LP-E17 power pack.

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 (USD)	Street Price
1.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
2.		Canon M6	112 mm	68 mm	45 mm	390 g	295	n	Feb 2017	779	ebay.com
3.		Canon M6 Mark II	120 mm	70 mm	49 mm	408 g	305	n	Aug 2019	849	ebay.com
4.		Canon 77D	131 mm	100 mm	76 mm	540 g	600	n	Feb 2017	899	ebay.com
5.		Canon M100	108 mm	67 mm	35 mm	302 g	295	n	Aug 2017	499	ebay.com
6.		Canon SL2	122 mm	93 mm	70 mm	453 g	650	n	Jun 2017	549	ebay.com
7.		Canon 5D Mark IV	151 mm	116 mm	76 mm	890 g	900	Y	Aug 2016	3,499	amazon.com
8.		Canon M5	116 mm	89 mm	61 mm	427 g	295	n	Sep 2016	979	ebay.com
9.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
10.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
11.		Canon 6D	145 mm	111 mm	71 mm	770 g	1090	Y	Sep 2012	2,099	ebay.com
12.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
13.		Canon 5D	152 mm	113 mm	75 mm	895 g	400	Y	Aug 2005	3,299	ebay.com
14.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
15.		Nikon D600	141 mm	113 mm	82 mm	850 g	900	Y	Sep 2012	2,099	ebay.com
16.		Nikon D800	146 mm	123 mm	82 mm	1000 g	900	Y	Feb 2012	2,999	ebay.com
17.		Nikon D800E	146 mm	123 mm	82 mm	1000 g	900	Y	Feb 2012	3,299	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 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 M6 was launched at a markedly lower price (by 78 percent) than the 5D Mark 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

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 5D Mark III features a full frame sensor and the Canon M6 an APS-C sensor. The sensor area in the M6 is 62 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.

Technology-wise, the M6 uses a more advanced image processing engine (DIGIC 7) than the 5D Mark III (DIGIC 5+), with benefits for noise reduction, color accuracy, and processing speed.

Despite having a smaller sensor, the M6 offers a slightly higher resolution of 24 megapixels, compared with 22.1 MP of the 5D Mark III. 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 3.72μm versus 6.25μm for the 5D Mark III). However, it should be noted that the M6 is much more recent (by 4 years and 11 months) than the 5D Mark III, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently.

The M6 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Canon EOS 5D Mark III has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 50-102400. The corresponding ISO settings for the Canon EOS M6 are ISO 100 to ISO 25600 (no boost).

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors. 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 Overall DXO ratings for the two cameras under consideration are close, suggesting that they provide similar imaging performance. 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 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
2.		Canon M6	APS-C	24.0	6000	4000	1080/60p	23.4	12.6	1317	78
3.		Canon M6 Mark II	APS-C	32.3	6960	4640	4K/30p	24.0	13.5	1848	83
4.		Canon 77D	APS-C	24.0	6000	4000	1080/60p	23.6	13.3	971	78
5.		Canon M100	APS-C	24.0	6000	4000	1080/60p	23.5	12.9	1272	78
6.		Canon SL2	APS-C	24.0	6000	4000	1080/60p	23.6	13.4	1041	79
7.		Canon 5D Mark IV	Full Frame	30.1	6720	4480	4K/30p	24.8	13.6	2995	91
8.		Canon M5	APS-C	24.0	6000	4000	1080/60p	23.4	12.4	1262	77
9.		Canon 5DS	Full Frame	50.3	8688	5792	1080/30p	24.7	12.4	2381	87
10.		Canon 5DS R	Full Frame	50.3	8688	5792	1080/30p	24.6	12.4	2308	86
11.		Canon 6D	Full Frame	20.0	5472	3648	1080/30p	23.8	12.1	2340	82
12.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
13.		Canon 5D	Full Frame	12.7	4368	2912	none	22.9	11.1	1368	71
14.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
15.		Nikon D600	Full Frame	24.2	6016	4016	1080/30p	25.1	14.2	2980	94
16.		Nikon D800	Full Frame	36.2	7360	4912	1080/30p	25.3	14.4	2853	95
17.		Nikon D800E	Full Frame	36.2	7360	4912	1080/30p	25.6	14.3	2979	96
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 M6 provides a faster frame rate than the 5D Mark III. It can shoot movie footage at 1080/60p, while the 5D Mark III is limited to 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the 5D Mark III has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the M6 relies on live view and the rear LCD for framing. That said, the M6 can be equipped with an optional viewfinder – the EVF-DC2. The adjacent table lists some of the other core features of the Canon 5D Mark III and Canon M6 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 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
2.		Canon M6	optional	n	3.0 / 1040	tilting	Y	1/4000s	9.0/s	Y	n
3.		Canon M6 Mark II	optional	n	3.0 / 1040	tilting	Y	1/4000s	14.0/s	Y	n
4.		Canon 77D	optical	Y	3.0 / 1040	swivel	Y	1/4000s	6.0/s	Y	n
5.		Canon M100	none	n	3.0 / 1040	tilting	Y	1/4000s	6.1/s	Y	n
6.		Canon SL2	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
7.		Canon 5D Mark IV	optical	Y	3.2 / 1620	fixed	Y	1/8000s	7.0/s	n	n
8.		Canon M5	2360	n	3.2 / 1620	tilting	Y	1/4000s	9.0/s	Y	n
9.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
10.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
11.		Canon 6D	optical	Y	3.0 / 1040	fixed	n	1/4000s	4.5/s	n	n
12.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
13.		Canon 5D	optical	Y	2.5 / 230	fixed	n	1/8000s	3.0/s	n	n
14.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
15.		Nikon D600	optical	Y	3.0 / 921	fixed	n	1/4000s	5.5/s	Y	n
16.		Nikon D800	optical	Y	3.2 / 921	fixed	n	1/8000s	4.0/s	Y	n
17.		Nikon D800E	optical	Y	3.2 / 921	fixed	n	1/8000s	4.0/s	Y	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the 5D Mark III, but is missing on the M6 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The Canon M6 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 5D Mark III writes its imaging data to Compact Flash or SDXC cards, while the M6 uses SDXC cards. The 5D Mark III features dual card slots, which can be very useful in case a memory card fails. In contrast, the M6 only has one slot. The M6 supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the 5D Mark III 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 EOS 5D Mark III and Canon EOS M6 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 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
2.		Canon M6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
3.		Canon M6 Mark II	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
4.		Canon 77D	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
5.		Canon M100	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
6.		Canon SL2	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
7.		Canon 5D Mark IV	Y	mono / mono	Y	Y	mini	3.0	Y	Y	-
8.		Canon M5	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
9.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
10.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
11.		Canon 6D	Y	mono / mono	Y	-	mini	2.0	Y	-	-
12.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
13.		Canon 5D	Y	- / -	-	-	-	2.0	-	-	-
14.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
15.		Nikon D600	Y	mono / mono	Y	Y	mini	2.0	-	-	-
16.		Nikon D800	Y	mono / mono	Y	Y	mini	3.0	-	-	-
17.		Nikon D800E	Y	mono / mono	Y	Y	mini	3.0	-	-	-

It is notable that the 5D Mark III has a headphone jack, which is not present on the M6 This port makes it possible to attach external headphones and monitor the quality of sound during the recording process.

Studio photographers will appreciate that the Canon 5D Mark III (unlike the M6) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 5D Mark III and the M6 have been discontinued, but can regularly be found used on ebay. The 5D Mark III was replaced by the Canon 5D Mark IV, while the M6 was followed by the Canon M6 Mark II. Further information on the features and operation of the 5D Mark III and M6 can be found, respectively, in the Canon 5D Mark III Manual (free pdf) or the online Canon M6 Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Canon 5D Mark III and the Canon M6? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Canon EOS 5D Mark III:

• Better low-light sensitivity: Requires less light for good images (0.8 stops ISO advantage).
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Easier setting verification: Features an LCD display on top to control shooting parameters.
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Longer lasting: Can take more shots (950 versus 295) on a single battery charge.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More heavily discounted: Has been available for much longer (launched in March 2012).

Arguments in favor of the Canon EOS M6:

• More dynamic range: Captures a broader range of light and dark details (0.9 EV of extra DR).
• Better jpgs: Has a more modern image processing engine (DIGIC 7 vs DIGIC 5+).
• Better video: Provides higher movie framerates (1080/60p versus 1080/30p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• More flexible LCD: Has a tilting screen for odd-angle shots in 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 burst: Shoots at higher frequency (9 vs 6 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (112x68mm vs 152x116mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 560g or 59 percent) and is thus easier to take along.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More affordable: Was introduced into a lower priced category (78 percent cheaper at launch).
• More modern: Reflects 4 years and 11 months of technical progress since the 5D Mark III launch.

If the count of individual advantages (bullet points above) is taken as a guide, the M6 is the clear winner of the contest (19 : 11 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 5D Mark III and the Canon M6 place the cameras among the top in their class? Find out in the latest Best DSLR 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 5D Mark III or the M6. 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 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
2.		Canon M6	..	..	..	80/100	4/5	4/5	Feb 2017	779	ebay.com
3.		Canon M6 Mark II	..	+	4.5/5	85/100	4/5	4/5	Aug 2019	849	ebay.com
4.		Canon 77D	4.5/5	..	4/5	82/100	4.5/5	4/5	Feb 2017	899	ebay.com
5.		Canon M100	3/5	+	..	..	4/5	3.5/5	Aug 2017	499	ebay.com
6.		Canon SL2	4/5	+ +	4/5	78/100	4.5/5	4.5/5	Jun 2017	549	ebay.com
7.		Canon 5D Mark IV	4.5/5	+ +	4/5	87/100	4.5/5	4.5/5	Aug 2016	3,499	amazon.com
8.		Canon M5	4/5	+	4/5	82/100	4/5	4/5	Sep 2016	979	ebay.com
9.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	3,699	ebay.com
10.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	3,699	ebay.com
11.		Canon 6D	5/5	+ +	..	83/100	4.5/5	4.5/5	Sep 2012	2,099	ebay.com
12.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
13.		Canon 5D	..	88/100	..	+ +	o	..	Aug 2005	3,299	ebay.com
14.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
15.		Nikon D600	4/5	+ +	..	87/100	5/5	4.5/5	Sep 2012	2,099	ebay.com
16.		Nikon D800	5/5	+ +	..	82/100	5/5	5/5	Feb 2012	2,999	ebay.com
17.		Nikon D800E	..	..	..	84/100	5/5	5/5	Feb 2012	3,299	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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

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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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