Canon M100 vs Pentax K-3 III

The Canon EOS M100 and the Pentax K-3 III are two digital cameras that were announced, respectively, in August 2017 and March 2021. The M100 is a mirrorless interchangeable lens camera, while the K-3 III is a DSLR. Both cameras are equipped with an APS-C sensor. The Canon has a resolution of 24 megapixels, whereas the Pentax provides 25.6 MP.

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

Headline Specifications

Canon M100		Pentax K-3 III
Mirrorless system camera		Digital single lens reflex
Canon EF-M mount lenses		Pentax K mount lenses
24 MP – APS-C sensor		25.6 MP – APS-C sensor
1080/60p Video		4K/30p Video
ISO 100-25,600		ISO 100-160,000
No viewfinder, LCD framing		Optical viewfinder
3.0" LCD – 1040k dots		3.2" LCD – 1620k dots
Tilting touchscreen		Fixed touchscreen
6.1 shutter flaps per second		12 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
295 shots per battery charge		800 shots per battery charge
108 x 67 x 35 mm, 302 g		135 x 104 x 74 mm, 820 g

Check M100 offers at
ebay.com
Check K-3 III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS M100 and the Pentax K-3 III? 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 M100 and the Pentax K-3 III is provided 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 dimensions are rounded to the nearest millimeter.

The M100 can be obtained in two different colors (black, white), while the K-3 III 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 III is considerably larger (94 percent) than the Canon M100. Moreover, the K-3 III is substantially heavier (172 percent) than the M100. It is noteworthy in this context that the K-3 III is splash and dust-proof, while the M100 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 M100 gets 295 shots out of its Canon LP-E12 battery, while the K-3 III can take 800 images on a single charge of its Pentax D-LI90 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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 M100	108 mm	67 mm	35 mm	302 g	295	n	Aug 2017	499	ebay.com
2.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
3.		Canon G9 X Mark II	98 mm	58 mm	31 mm	206 g	235	n	Jan 2017	529	ebay.com
4.		Canon M	109 mm	66 mm	32 mm	298 g	230	n	Jul 2012	599	ebay.com
5.		Canon M3	111 mm	68 mm	44 mm	366 g	250	n	Feb 2015	679	ebay.com
6.		Canon M5	116 mm	89 mm	61 mm	427 g	295	n	Sep 2016	979	ebay.com
7.		Canon M6	112 mm	68 mm	45 mm	390 g	295	n	Feb 2017	779	ebay.com
8.		Canon M10	108 mm	67 mm	35 mm	301 g	255	n	Oct 2015	499	ebay.com
9.		Canon M50	116 mm	88 mm	59 mm	390 g	235	n	Feb 2018	779	ebay.com
10.		Canon M200	108 mm	67 mm	35 mm	299 g	315	n	Sep 2019	549	ebay.com
11.		Canon SL2	122 mm	93 mm	70 mm	453 g	650	n	Jun 2017	549	ebay.com
12.		Canon T7	129 mm	101 mm	78 mm	475 g	500	n	Feb 2018	449	amazon.com
13.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	1,899	ebay.com
14.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
15.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
16.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
17.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The M100 was launched at a markedly lower price (by 75 percent) than the K-3 III, 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.

Sensor comparison

The size of the imaging sensor is a crucial determinant 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 more expensive and lead to bigger and heavier cameras 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 III is 9 percent bigger. As a result of these sensor size differences, the cameras have format factors, respectively, of 1.6 (M100) and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 25.6MP, the K-3 III offers a higher resolution than the M100 (24MP), but the K-3 III nevertheless has marginally larger individual pixels (pixel pitch of 3.76μm versus 3.72μm for the M100) due to its larger sensor. Moreover, the K-3 III is a much more recent model (by 3 years and 7 months) than the M100, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the K-3 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The M100 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

Unlike the M100, the K-3 III has the capacity to capture high quality composite images (YESMP) by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

The Canon EOS M100 has a native sensitivity range from ISO 100 to ISO 25600. The corresponding ISO settings for the Pentax K-3 III are ISO 100 to ISO 160000 (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 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 table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar 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 M100	APS-C	24.0	6000	4000	1080/60p	23.5	12.9	1272	78
2.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
3.		Canon G9 X Mark II	1-inch	20.0	5472	3648	1080/60p	21.9	12.5	522	65
4.		Canon M	APS-C	17.9	5184	3456	1080/30p	22.1	11.2	827	65
5.		Canon M3	APS-C	24.0	6000	4000	1080/30p	22.8	11.8	1169	72
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 M10	APS-C	17.9	5184	3456	1080/30p	22.2	11.4	753	65
9.		Canon M50	APS-C	24.0	6000	4000	4K/24p	23.8	13.3	1684	81
10.		Canon M200	APS-C	24.0	6000	4000	4k/25p	24.0	13.5	1836	82
11.		Canon SL2	APS-C	24.0	6000	4000	1080/60p	23.6	13.4	1041	79
12.		Canon T7	APS-C	24.0	6000	4000	1080/30p	23.8	13.3	1684	81
13.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
14.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
15.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
16.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
17.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
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 also of capturing video footage. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the K-3 III provides a better video resolution than the M100. It can shoot movie footage at 4K/30p, while the Canon is limited to 1080/60p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the K-3 III has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the M100 relies on live view and the rear LCD for framing. The adjacent table lists some of the other core features of the Canon M100 and Pentax K-3 III 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 M100	none	n	3.0 / 1040	tilting	Y	1/4000s	6.1/s	Y	n
2.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
3.		Canon G9 X Mark II	none	n	3.0 / 1040	fixed	Y	1/2000s	8.2/s	Y	Y
4.		Canon M	none	n	3.0 / 1040	fixed	Y	1/4000s	4.3/s	n	n
5.		Canon M3	optional	n	3.0 / 1040	tilting	Y	1/4000s	4.2/s	Y	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 M10	none	n	3.0 / 1040	tilting	Y	1/4000s	4.6/s	Y	n
9.		Canon M50	2360	n	3.0 / 1040	swivel	Y	1/4000s	10.0/s	Y	n
10.		Canon M200	none	n	3.0 / 1040	tilting	Y	1/4000s	6.1/s	Y	n
11.		Canon SL2	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
12.		Canon T7	optical	n	3.0 / 920	fixed	n	1/4000s	3.0/s	Y	n
13.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
14.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
15.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
16.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
17.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
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 M100 has one, while the K-3 III does not. While the built-in flash of the M100 is not very powerful, it can at times be useful as a fill-in light.

The Pentax K-3 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.

Concerning the storage of imaging data, both the M100 and the K-3 III write their files to SDXC cards. The K-3 III features dual card slots, which can be very useful in case a memory card fails. In contrast, the M100 only has one slot. The K-3 III supports UHS-II cards (on its first slot), while the M100 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 Canon EOS M100 and Pentax K-3 III 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 M100	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
2.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
3.		Canon G9 X Mark II	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
4.		Canon M	Y	stereo / mono	Y	-	mini	2.0	-	-	-
5.		Canon M3	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
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 M10	-	stereo / mono	-	-	mini	2.0	Y	Y	-
9.		Canon M50	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
10.		Canon M200	-	stereo / mono	-	-	micro	2.0	Y	-	Y
11.		Canon SL2	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
12.		Canon T7	Y	mono / mono	-	-	mini	2.0	Y	Y	-
13.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
14.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
16.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
17.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-

It is notable that the K-3 III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The M100 lacks such a headphone port.

Studio photographers will appreciate that the Pentax K-3 III (unlike the M100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Travel and landscape photographers will find it useful that the K-3 III has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

The K-3 III is a recent model that features in the current product line-up of Pentax. In contrast, the M100 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the M100 was succeeded by the Canon M200. Further information on the features and operation of the M100 and K-3 III can be found, respectively, in the Canon M100 Manual (free pdf) or the online Pentax K-3 III Manual.

Review summary

So how do things add up? Is there a clear favorite between the Canon M100 and the Pentax K-3 III? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Canon EOS M100:

• 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.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• More compact: Is smaller (108x67mm vs 135x104mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 518g or 63 percent) and hence easier to carry around.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More affordable: Was introduced into a lower priced category (75 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2017).

Arguments in favor of the Pentax K-3 III:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• 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.
• More detailed LCD: Has a higher resolution rear screen (1620k vs 1040k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (12 vs 6.1 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 (800 versus 295) 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.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• Faster data transfer: Supports a more advanced USB protocol (3.2 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.
• Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
• More modern: Reflects 3 years and 7 months of technical progress since the M100 launch.

If the number of relative strengths (bullet points above) is taken as a guide, the K-3 III is the clear winner of the contest (22 : 11 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 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 M100 and the Pentax K-3 III 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 M100 and the K-3 III 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 hands-on reviews by experts are important. The following table reports the overall ratings of the cameras as published by some of the major 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 M100	3/5	+	..	..	4/5	3.5/5	Aug 2017	499	ebay.com
2.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
3.		Canon G9 X Mark II	4/5	..	4/5	75/100	4.5/5	4.5/5	Jan 2017	529	ebay.com
4.		Canon M	3/5	+	..	..	4/5	4/5	Jul 2012	599	ebay.com
5.		Canon M3	4/5	o	..	75/100	4.5/5	4/5	Feb 2015	679	ebay.com
6.		Canon M5	4/5	+	4/5	82/100	4/5	4/5	Sep 2016	979	ebay.com
7.		Canon M6	..	..	..	80/100	4/5	4/5	Feb 2017	779	ebay.com
8.		Canon M10	..	..	..	..	..	4/5	Oct 2015	499	ebay.com
9.		Canon M50	..	+	4/5	79/100	..	3.5/5	Feb 2018	779	ebay.com
10.		Canon M200	..	+	3/5	79/100	4/5	4/5	Sep 2019	549	ebay.com
11.		Canon SL2	4/5	+ +	4/5	78/100	4.5/5	4.5/5	Jun 2017	549	ebay.com
12.		Canon T7	..	o	3.5/5	..	3.5/5	3.5/5	Feb 2018	449	amazon.com
13.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	1,899	ebay.com
14.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
15.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
16.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
17.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, 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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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 are interested in seeing how other cameras pair up, 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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