Canon M3 vs Pentax K-S1

The Canon EOS M3 and the Pentax K-S1 are two digital cameras that were announced, respectively, in February 2015 and August 2014. The M3 is a mirrorless interchangeable lens camera, while the K-S1 is a DSLR. Both cameras are equipped with an APS-C sensor. The Canon has a resolution of 24 megapixels, whereas the Pentax provides 20 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-S1
Mirrorless system camera		Digital single lens reflex
Canon EF-M mount lenses		Pentax K mount lenses
24 MP – APS-C sensor		20 MP – APS-C sensor
1080/30p Video		1080/30p Video
ISO 100-12,800 (100 - 25,600)		ISO 100-51,200
Viewfinder optional		Optical viewfinder
3.0" LCD – 1040k dots		3.0" LCD – 921k dots
Tilting touchscreen		Fixed screen (not touch-sensitive)
4.2 shutter flaps per second		5.4 shutter flaps per second
Lens stabilization only		In-body stabilization
250 shots per battery charge		410 shots per battery charge
111 x 68 x 44 mm, 366 g		121 x 93 x 70 mm, 558 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-S1? 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 M3 and the Pentax K-S1 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 width, height and depth dimensions are rounded to the nearest millimeter.

The M3 can be obtained in two different colors (black, white), while the K-S1 is available in four color-versions (black, grey, orange, white).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-S1 is considerably larger (49 percent) than the Canon M3. Moreover, the K-S1 is substantially heavier (52 percent) than the M3. In this context, it is worth noting that neither the M3 nor the K-S1 are weather-sealed.

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-S1 can take 410 images on a single charge of its Pentax D-LI109 power pack.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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 M3	111 mm	68 mm	44 mm	366 g	250	n	Feb 2015	US$ 679	ebay.com
2.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	US$ 749	ebay.com
3.		Canon G5 X	112 mm	76 mm	44 mm	353 g	210	n	Oct 2015	US$ 799	ebay.com
4.		Canon G7 X	103 mm	60 mm	40 mm	304 g	210	n	Sep 2014	US$ 699	ebay.com
5.		Canon M	109 mm	66 mm	32 mm	298 g	230	n	Jul 2012	US$ 599	ebay.com
6.		Canon M5	116 mm	89 mm	61 mm	427 g	295	n	Sep 2016	US$ 979	ebay.com
7.		Canon M6	112 mm	68 mm	45 mm	390 g	295	n	Feb 2017	US$ 779	ebay.com
8.		Canon M50	116 mm	88 mm	59 mm	390 g	235	n	Feb 2018	US$ 779	ebay.com
9.		Canon M50 Mark II	116 mm	88 mm	59 mm	387 g	305	n	Oct 2020	US$ 599	ebay.com
10.		Canon M100	108 mm	67 mm	35 mm	302 g	295	n	Aug 2017	US$ 499	ebay.com
11.		Canon T6i	132 mm	101 mm	78 mm	555 g	440	n	Feb 2015	US$ 749	ebay.com
12.		Canon T6s	132 mm	101 mm	78 mm	565 g	440	n	Feb 2015	US$ 649	ebay.com
13.		Nikon D5300	125 mm	98 mm	76 mm	480 g	600	n	Oct 2013	US$ 799	ebay.com
14.		Nikon D5500	124 mm	97 mm	70 mm	470 g	820	n	Jan 2015	US$ 899	ebay.com
15.		Pentax K-500	130 mm	97 mm	71 mm	646 g	710	n	Jun 2013	US$ 549	ebay.com
16.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	US$ 749	ebay.com
17.		Sony A68	143 mm	104 mm	81 mm	610 g	540	n	Nov 2015	US$ 699	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 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 somewhat cheaper (by 9 percent) than the K-S1 at launch, but both cameras fall into the same price category. 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 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. 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.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the K-S1 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.

Despite having a smaller sensor, the Canon M3 offers a higher resolution of 24 megapixels, compared with 20 MP of the Pentax K-S1. 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 4.28μm for the K-S1). However, it should be noted that the M3 is a somewhat more recent model (by 5 months) than the K-S1, and its sensor might have benefitted from technological advances during this time that partly offset its pixel-size disadvantage. Coming back to sensor resolution, it should be mentioned that the K-S1 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Canon M3 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the M3 for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the Pentax K-S1 are 27.4 x 18.2 inches or 69.5 x 46.3 cm for good quality, 21.9 x 14.6 inches or 55.6 x 37.1 cm for very good quality, and 18.2 x 12.2 inches or 46.3 x 30.9 cm for excellent quality prints.

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-S1 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.

For many cameras, data on sensor performance has been reported by DXO Mark. 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-S1 has a markedly higher DXO score than the M3 (overall score 6 points higher), which will translate into better image quality. The advantage is based on 0.7 bits higher color depth, 1.2 EV in additional dynamic range, and 0.1 stops of reduced low light sensitivity. 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 M3	APS-C	24.0	6000	4000	1080/30p	22.8	11.8	1169	72
2.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
3.		Canon G5 X	1-inch	20.0	5472	3648	1080/60p	21.4	12.3	471	62
4.		Canon G7 X	1-inch	20.0	5472	3648	1080/60p	23.0	12.7	556	71
5.		Canon M	APS-C	17.9	5184	3456	1080/30p	22.1	11.2	827	65
6.		Canon M5	APS-C	24.0	6000	4000	1080/60p	23.4	12.4	1262	77
7.		Canon M6	APS-C	24.0	6000	4000	1080/60p	23.4	12.6	1317	78
8.		Canon M50	APS-C	24.0	6000	4000	4K/24p	23.8	13.3	1684	81
9.		Canon M50 Mark II	APS-C	24.0	6000	4000	4K/24p	24.0	13.6	1939	83
10.		Canon M100	APS-C	24.0	6000	4000	1080/60p	23.5	12.9	1272	78
11.		Canon T6i	APS-C	24.0	6000	4000	1080/30p	22.7	12.0	919	71
12.		Canon T6s	APS-C	24.0	6000	4000	1080/30p	22.6	12.0	915	70
13.		Nikon D5300	APS-C	24.0	6000	4000	1080/60p	24.0	13.9	1338	83
14.		Nikon D5500	APS-C	24.0	6000	4000	1080/60p	24.1	14.0	1438	84
15.		Pentax K-500	APS-C	16.1	4928	3264	1080/30p	23.7	13.1	1087	79
16.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
17.		Sony A68	APS-C	24.0	6000	4000	1080/60i	24.1	13.5	701	79
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, and both provide the same movie specifications (1080/30p).

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the K-S1 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 following table reports on some other key feature differences and similarities of the Canon M3, the Pentax K-S1, 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 M3	optional	n	3.0 / 1040	tilting	Y	1/4000s	4.2/s	Y	n
2.		Pentax K-S1	optical	n	3.0 / 921	fixed	n	1/6000s	5.4/s	Y	Y
3.		Canon G5 X	2360	n	3.0 / 1040	swivel	Y	1/2000s	5.9/s	Y	Y
4.		Canon G7 X	none	n	3.0 / 1040	tilting	Y	1/2000s	6.5/s	Y	Y
5.		Canon M	none	n	3.0 / 1040	fixed	Y	1/4000s	4.3/s	n	n
6.		Canon M5	2360	n	3.2 / 1620	tilting	Y	1/4000s	9.0/s	Y	n
7.		Canon M6	optional	n	3.0 / 1040	tilting	Y	1/4000s	9.0/s	Y	n
8.		Canon M50	2360	n	3.0 / 1040	swivel	Y	1/4000s	10.0/s	Y	n
9.		Canon M50 Mark II	2360	n	3.0 / 1040	swivel	Y	1/4000s	10.0/s	Y	n
10.		Canon M100	none	n	3.0 / 1040	tilting	Y	1/4000s	6.1/s	Y	n
11.		Canon T6i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
12.		Canon T6s	optical	Y	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
13.		Nikon D5300	optical	n	3.2 / 1037	swivel	n	1/4000s	5.0/s	Y	n
14.		Nikon D5500	optical	n	3.2 / 1037	swivel	Y	1/4000s	5.0/s	Y	n
15.		Pentax K-500	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
16.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
17.		Sony A68	1440	Y	2.7 / 460	tilting	n	1/4000s	8.0/s	Y	Y
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-S1 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

Concerning the storage of imaging data, both the M3 and the K-S1 write their files to SDXC 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 EOS M3 and Pentax K-S1 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-S1	Y	stereo / mono	-	-	micro	2.0	-	-	-
3.		Canon G5 X	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
4.		Canon G7 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
5.		Canon M	Y	stereo / mono	Y	-	mini	2.0	-	-	-
6.		Canon M5	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
7.		Canon M6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
8.		Canon M50	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
9.		Canon M50 Mark II	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
10.		Canon M100	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
11.		Canon T6i	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
12.		Canon T6s	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
13.		Nikon D5300	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
14.		Nikon D5500	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
15.		Pentax K-500	Y	mono / mono	-	-	-	2.0	-	-	-
16.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
17.		Sony A68	Y	stereo / mono	Y	-	micro	2.0	-	-	-

It is notable that the M3 has a microphone port, which is missing on the K-S1. Such an external microphone input can help to substantially improve the quality of audio recordings when a good external microphone is used.

Both the M3 and the K-S1 have been discontinued, but can regularly be found used on ebay. The K-S1 was replaced by the Pentax K-S2, while the M3 was followed by the Canon M6. Further information on the features and operation of the M3 and K-S1 can be found, respectively, in the Canon M3 Manual (free pdf) or the online Pentax K-S1 Manual.

Review summary

So what conclusions can be drawn? Which of the two cameras – the Canon M3 or the Pentax K-S1 – 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 Canon EOS M3:

• More detail: Offers more megapixels (24 vs 20MP) with a 10% higher linear resolution.
• 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.
• Better sound: Can connect to an external microphone for higher quality sound recording.
• More detailed LCD: Has a higher resolution rear screen (1040k vs 921k dots).
• 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 121x93mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 192g or 34 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 modern: Is somewhat more recent (announced 5 months after the K-S1).

Reasons to prefer the Pentax K-S1:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores markedly higher (6 points) in the DXO overall evaluation.
• More dynamic range: Captures a broader range of light and dark details (1.2 EV of extra DR).
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Faster shutter: Has higher mechanical shutter speed (1/6000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (5.4 vs 4.2 flaps/sec) to capture the decisive moment.
• Longer lasting: Gets more shots (410 versus 250) out of a single battery charge.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• More heavily discounted: Has been on the market for longer (launched in August 2014).

If the number of relative strengths (bullet points above) is taken as a guide, the M3 is the clear winner of the match-up (14 : 9 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 Canon M3 and the Pentax K-S1 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 technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the M3 and the K-S1 in practical situations. 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 expert reviews 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 M3	4/5	o	..	75/100	4.5/5	4/5	Feb 2015	US$ 679	ebay.com
2.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	US$ 749	ebay.com
3.		Canon G5 X	5/5	+ +	..	78/100	4.5/5	4.5/5	Oct 2015	US$ 799	ebay.com
4.		Canon G7 X	4/5	+ +	..	77/100	4.5/5	4.5/5	Sep 2014	US$ 699	ebay.com
5.		Canon M	3/5	+	..	..	4/5	4/5	Jul 2012	US$ 599	ebay.com
6.		Canon M5	4/5	+	4/5	82/100	4/5	4/5	Sep 2016	US$ 979	ebay.com
7.		Canon M6	..	..	..	80/100	4/5	4/5	Feb 2017	US$ 779	ebay.com
8.		Canon M50	..	+	4/5	79/100	..	3.5/5	Feb 2018	US$ 779	ebay.com
9.		Canon M50 Mark II	4/5	..	4/5	..	4.5/5	3.5/5	Oct 2020	US$ 599	ebay.com
10.		Canon M100	3/5	+	..	..	4/5	3.5/5	Aug 2017	US$ 499	ebay.com
11.		Canon T6i	5/5	..	..	75/100	4.5/5	4.5/5	Feb 2015	US$ 749	ebay.com
12.		Canon T6s	5/5	+	..	77/100	4.5/5	4.5/5	Feb 2015	US$ 649	ebay.com
13.		Nikon D5300	4/5	+ +	..	79/100	4.5/5	4.5/5	Oct 2013	US$ 799	ebay.com
14.		Nikon D5500	5/5	+	..	79/100	4.5/5	4.5/5	Jan 2015	US$ 899	ebay.com
15.		Pentax K-500	..	..	..	..	4.5/5	4.5/5	Jun 2013	US$ 549	ebay.com
16.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	US$ 749	ebay.com
17.		Sony A68	3/5	..	..	..	4/5	4/5	Nov 2015	US$ 699	ebay.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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. Also, please note that some of the review sites have changed their methodology and reporting over time.

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Other camera comparisons

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