Canon M3 vs Pentax K-3

The Canon EOS M3 and the Pentax K-3 are two digital cameras that were announced, respectively, in February 2015 and October 2013. The M3 is a mirrorless interchangeable lens camera, while the K-3 is a DSLR. Both cameras are equipped with an APS-C sensor. The Canon has a resolution of 24 megapixels, whereas the Pentax provides 24.1 MP.

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

Headline Specifications

Canon M3		Pentax K-3
Mirrorless system camera		Digital single lens reflex
Canon EF-M mount lenses		Pentax K mount lenses
24 MP – APS-C sensor		24.1 MP – APS-C sensor
1080/30p Video		1080/60i Video
ISO 100-12,800 (100 - 25,600)		ISO 100-51,200
Viewfinder optional		Optical viewfinder
3.0" LCD – 1040k dots		3.2" LCD – 1037k dots
Tilting touchscreen		Fixed screen (not touch-sensitive)
4.2 shutter flaps per second		8.3 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
250 shots per battery charge		560 shots per battery charge
111 x 68 x 44 mm, 366 g		131 x 100 x 77 mm, 800 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS M3 and the Pentax K-3? 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 M3 and the Pentax K-3 are illustrated 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 M3 can be obtained in two different colors (black, white), while the K-3 is also available in two color-versions, but different ones (black, silver).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-3 is considerably larger (74 percent) than the Canon M3. Moreover, the K-3 is substantially heavier (119 percent) than the M3. It is noteworthy in this context that the K-3 is splash and dust-proof, 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 M3 gets 250 shots out of its Canon LP-E17 battery, while the K-3 can take 560 images on a single charge of its Pentax D-LI90 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 M3	111 mm	68 mm	44 mm	366 g	250	n	Feb 2015	679	ebay.com
2.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
3.		Canon M6	112 mm	68 mm	45 mm	390 g	295	n	Feb 2017	779	ebay.com
4.		Canon M100	108 mm	67 mm	35 mm	302 g	295	n	Aug 2017	499	ebay.com
5.		Canon G7 X Mark II	106 mm	61 mm	42 mm	319 g	265	n	Feb 2016	699	ebay.com
6.		Canon M5	116 mm	89 mm	61 mm	427 g	295	n	Sep 2016	979	ebay.com
7.		Canon 750D	132 mm	101 mm	78 mm	555 g	440	n	Feb 2015	749	ebay.com
8.		Canon G5 X	112 mm	76 mm	44 mm	353 g	210	n	Oct 2015	799	ebay.com
9.		Canon M10	108 mm	67 mm	35 mm	301 g	255	n	Oct 2015	499	ebay.com
10.		Canon G7 X	103 mm	60 mm	40 mm	304 g	210	n	Sep 2014	699	ebay.com
11.		Canon 70D	139 mm	104 mm	79 mm	755 g	920	Y	Jul 2013	1,199	ebay.com
12.		Canon M	109 mm	66 mm	32 mm	298 g	230	n	Jul 2012	599	ebay.com
13.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
14.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
15.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	1,099	ebay.com
16.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	1,099	ebay.com
17.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	599	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

The price is, of course, an important factor in any camera decision. 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 48 percent) than the K-3, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units in a sensor of the same technological generation. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the background. On the downside, larger sensors tend to be associated with larger, more expensive camera bodies and lenses.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the K-3 is 11 percent bigger. As a result of these sensor size differences, the cameras have format factors, respectively, of 1.6 (M3) and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 24.1MP, the K-3 offers a higher resolution than the M3 (24MP), but the K-3 nevertheless has larger individual pixels (pixel pitch of 3.90μm versus 3.72μm for the M3) due to its larger sensor. However, the M3 is a somewhat more recent model (by 1 year and 4 months) than the K-3, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the K-3 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The M3 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Canon EOS M3 has a native sensitivity range from ISO 100 to ISO 12800, which can be extended to ISO 100-25600. The corresponding ISO settings for the Pentax K-3 are ISO 100 to ISO 51200 (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.

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 K-3 has a markedly higher DXO score than the M3 (overall score 8 points higher), which will translate into better image quality. The advantage is based on 0.9 bits higher color depth, 1.6 EV in additional dynamic range, and 0.1 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 M3	APS-C	24.0	6000	4000	1080/30p	22.8	11.8	1169	72
2.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
3.		Canon M6	APS-C	24.0	6000	4000	1080/60p	23.4	12.6	1317	78
4.		Canon M100	APS-C	24.0	6000	4000	1080/60p	23.5	12.9	1272	78
5.		Canon G7 X Mark II	1-inch	20.0	5472	3648	1080/60p	21.8	11.9	260	62
6.		Canon M5	APS-C	24.0	6000	4000	1080/60p	23.4	12.4	1262	77
7.		Canon 750D	APS-C	24.0	6000	4000	1080/30p	22.7	12.0	919	71
8.		Canon G5 X	1-inch	20.0	5472	3648	1080/60p	21.4	12.3	471	62
9.		Canon M10	APS-C	17.9	5184	3456	1080/30p	22.2	11.4	753	65
10.		Canon G7 X	1-inch	20.0	5472	3648	1080/60p	23.0	12.7	556	71
11.		Canon 70D	APS-C	20.0	5472	3648	1080/30p	22.5	11.6	926	68
12.		Canon M	APS-C	17.9	5184	3456	1080/30p	22.1	11.2	827	65
13.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
14.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
15.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
16.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
17.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
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 K-3 provides a faster frame rate than the M3. It can shoot movie footage at 1080/60i, while the Canon is limited to 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the K-3 has an optical viewfinder, which can be very useful 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 Canon M3 and Pentax K-3 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 M3	optional	n	3.0 / 1040	tilting	Y	1/4000s	4.2/s	Y	n
2.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
3.		Canon M6	optional	n	3.0 / 1040	tilting	Y	1/4000s	9.0/s	Y	n
4.		Canon M100	none	n	3.0 / 1040	tilting	Y	1/4000s	6.1/s	Y	n
5.		Canon G7 X Mark II	none	n	3.0 / 1040	tilting	Y	1/2000s	8.0/s	Y	Y
6.		Canon M5	2360	n	3.2 / 1620	tilting	Y	1/4000s	9.0/s	Y	n
7.		Canon 750D	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
8.		Canon G5 X	2360	n	3.0 / 1040	swivel	Y	1/2000s	5.9/s	Y	Y
9.		Canon M10	none	n	3.0 / 1040	tilting	Y	1/4000s	4.6/s	Y	n
10.		Canon G7 X	none	n	3.0 / 1040	tilting	Y	1/2000s	6.5/s	Y	Y
11.		Canon 70D	optical	Y	3.0 / 1040	swivel	Y	1/8000s	7.0/s	Y	n
12.		Canon M	none	n	3.0 / 1040	fixed	Y	1/4000s	4.3/s	n	n
13.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
14.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
15.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
16.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
17.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The M3 has a touchscreen, while the K-3 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

The Pentax K-3 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.

Concerning the storage of imaging data, both the M3 and the K-3 write their files to SDXC cards. The K-3 features dual card slots, which can be very useful in case a memory card fails. In contrast, the M3 only has one slot. 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 EOS M3 and Pentax K-3 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 M3	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
2.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
3.		Canon M6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
4.		Canon M100	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
5.		Canon G7 X Mark II	-	stereo / mono	-	-	micro	2.0	Y	Y	-
6.		Canon M5	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
7.		Canon 750D	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
8.		Canon G5 X	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
9.		Canon M10	-	stereo / mono	-	-	mini	2.0	Y	Y	-
10.		Canon G7 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
11.		Canon 70D	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
12.		Canon M	Y	stereo / mono	Y	-	mini	2.0	-	-	-
13.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
14.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
17.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-

It is notable that the M3 offers wifi support, while the K-3 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Studio photographers will appreciate that the Pentax K-3 (unlike the M3) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the M3 and the K-3 have been discontinued, but can regularly be found used on ebay. The K-3 was replaced by the Pentax K-3 II, while the M3 was followed by the Canon M6. Further information on the features and operation of the M3 and K-3 can be found, respectively, in the Canon M3 Manual (free pdf) or the online Pentax K-3 Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Canon M3 and the Pentax K-3? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Canon EOS M3:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• 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: 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.
• More compact: Is smaller (111x68mm vs 131x100mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 434g or 54 percent) and hence easier to carry around.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• 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.
• More affordable: Was introduced into a lower priced category (48 percent cheaper at launch).
• More modern: Is somewhat more recent (announced 1 year and 4 months after the K-3).

Advantages of the Pentax K-3:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores markedly higher (8 points) in the DXO overall evaluation.
• More dynamic range: Captures a broader range of light and dark details (1.6 EV of extra DR).
• Better video: Provides higher movie framerates (1080/60i versus 1080/30p).
• 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 a control panel on top to check 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.
• Faster burst: Shoots at higher frequency (8.3 vs 4.2 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Gets more shots (560 versus 250) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
• 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 on the market for longer (launched in October 2013).

If the count of individual advantages (bullet points above) is taken as a guide, the K-3 is the clear winner of the contest (18 : 12 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 M3 and the Pentax K-3 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best DSLR 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 says little about, for example, the shooting experience and imaging performance of the M3 and the K-3 in practical situations. 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 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.		Canon M3	4/5	o	..	75/100	4.5/5	4/5	Feb 2015	679	ebay.com
2.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
3.		Canon M6	..	..	..	80/100	4/5	4/5	Feb 2017	779	ebay.com
4.		Canon M100	3/5	+	..	..	4/5	3.5/5	Aug 2017	499	ebay.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 M5	4/5	+	4/5	82/100	4/5	4/5	Sep 2016	979	ebay.com
7.		Canon 750D	5/5	..	..	75/100	4.5/5	4.5/5	Feb 2015	749	ebay.com
8.		Canon G5 X	5/5	+ +	..	78/100	4.5/5	4.5/5	Oct 2015	799	ebay.com
9.		Canon M10	..	..	..	..	..	4/5	Oct 2015	499	ebay.com
10.		Canon G7 X	4/5	+ +	..	77/100	4.5/5	4.5/5	Sep 2014	699	ebay.com
11.		Canon 70D	5/5	+ +	..	83/100	4.5/5	5/5	Jul 2013	1,199	ebay.com
12.		Canon M	3/5	+	..	..	4/5	4/5	Jul 2012	599	ebay.com
13.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
14.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
15.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	1,099	ebay.com
16.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	1,099	ebay.com
17.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	599	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, 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

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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.

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