Pentax K-S1 vs MX-1

The Pentax K-S1 and the Pentax MX-1 are two digital cameras that were announced, respectively, in August 2014 and January 2013. The K-S1 is a DSLR, while the MX-1 is a fixed lens compact. The cameras are based on an APS-C (K-S1) and a 1/1.7-inch (MX-1) sensor. The K-S1 has a resolution of 20 megapixels, whereas the MX-1 provides 12 MP.

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

Headline Specifications

Pentax K-S1		Pentax MX-1
Digital single lens reflex		Fixed lens compact camera
Pentax K mount lenses		28-112mm f/1.8-2.5
20 MP – APS-C sensor		12 MP – 1/1.7" sensor
1080/30p Video		1080/30p Video
ISO 100-51,200		ISO 100-12,800
Optical viewfinder		No viewfinder, LCD framing
3.0" LCD – 921k dots		3.0" LCD – 920k dots
Fixed screen (not touch-sensitive)		Tilting screen (no touchscreen)
5.4 shutter flaps per second		1 shutter flaps per second
In-body stabilization		In-body stabilization
410 shots per battery charge		290 shots per battery charge
121 x 93 x 70 mm, 558 g		122 x 61 x 51 mm, 391 g

Check K-S1 offers at
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Check MX-1 offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-S1 and the Pentax MX-1? 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 Pentax K-S1 and the Pentax MX-1 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 size dimensions are rounded to the nearest millimeter.

The K-S1 can be obtained in four different colors (black, grey, orange, white), while the MX-1 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 Pentax MX-1 is considerably smaller (34 percent) than the Pentax K-S1. In this context, it is worth noting that neither the K-S1 nor the MX-1 are weather-sealed.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the MX-1 has a lens built in, whereas the K-S1 is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.

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	Street Price
1.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	US$ 749	ebay.com
2.		Pentax MX-1	122 mm	61 mm	51 mm	391 g	290	n	Jan 2013	US$ 499	ebay.com
3.		Canon G15	107 mm	76 mm	40 mm	352 g	350	n	Sep 2012	US$ 499	ebay.com
4.		Canon G16	109 mm	76 mm	40 mm	356 g	360	n	Aug 2013	US$ 549	ebay.com
5.		Nikon D5300	125 mm	98 mm	76 mm	480 g	600	n	Oct 2013	US$ 799	ebay.com
6.		Nikon D5500	124 mm	97 mm	70 mm	470 g	820	n	Jan 2015	US$ 899	ebay.com
7.		Nikon P7800	119 mm	78 mm	50 mm	399 g	350	n	Sep 2013	US$ 549	ebay.com
8.		Olympus XZ-2	113 mm	65 mm	48 mm	346 g	340	n	Sep 2012	US$ 599	ebay.com
9.		Panasonic LF1	103 mm	62 mm	28 mm	192 g	250	n	Apr 2013	US$ 499	ebay.com
10.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	US$ 1 299	ebay.com
11.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	US$ 1 099	ebay.com
12.		Pentax K-30	130 mm	97 mm	71 mm	650 g	410	Y	May 2012	US$ 849	ebay.com
13.		Pentax K-50	130 mm	97 mm	71 mm	650 g	410	Y	Jun 2013	US$ 599	ebay.com
14.		Pentax K-500	130 mm	97 mm	71 mm	646 g	710	n	Jun 2013	US$ 549	ebay.com
15.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	US$ 749	ebay.com
16.		Sony A58	129 mm	95 mm	78 mm	492 g	690	n	Feb 2013	US$ 599	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 MX-1 was launched at a lower price than the K-S1, despite having a lens built in. 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 Pentax K-S1 features an APS-C sensor and the Pentax MX-1 a 1/1.7-inch sensor. The sensor area in the MX-1 is 88 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 4.5. The sensor in the K-S1 has a native 3:2 aspect ratio, while the one in the MX-1 offers a 4:3 aspect.

With 20MP, the K-S1 offers a higher resolution than the MX-1 (12MP), but the K-S1 nevertheless has larger individual pixels (pixel pitch of 4.28μm versus 1.89μm for the MX-1) due to its larger sensor. Moreover, the K-S1 is a somewhat more recent model (by 1 year and 7 months) than the MX-1, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. 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 Pentax K-S1 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-S1 for good quality output (200 dots per inch) amounts to 27.4 x 18.2 inches or 69.5 x 46.3 cm, for very good quality (250 dpi) 21.9 x 14.6 inches or 55.6 x 37.1 cm, and for excellent quality (300 dpi) 18.2 x 12.2 inches or 46.3 x 30.9 cm. The corresponding values for the Pentax MX-1 are 20 x 15 inches or 50.8 x 38.1 cm for good quality, 16 x 12 inches or 40.6 x 30.5 cm for very good quality, and 13.3 x 10 inches or 33.9 x 25.4 cm for excellent quality prints.

The Pentax K-S1 has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Pentax MX-1 are ISO 100 to ISO 12800 (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 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 K-S1 provides substantially higher image quality than the MX-1, with an overall score that is 29 points higher. This advantage is based on 3.1 bits higher color depth, 1.7 EV in additional dynamic range, and 2.4 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.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
2.		Pentax MX-1	1/1.7	12.0	4000	3000	1080/30p	20.4	11.3	208	49
3.		Canon G15	1/1.7	12.0	4000	3000	1080/24p	19.9	11.5	165	46
4.		Canon G16	1/1.7	12.0	4000	3000	1080/60p	21.0	11.7	230	54
5.		Nikon D5300	APS-C	24.0	6000	4000	1080/60p	24.0	13.9	1338	83
6.		Nikon D5500	APS-C	24.0	6000	4000	1080/60p	24.1	14.0	1438	84
7.		Nikon P7800	1/1.7	12.0	4000	3000	1080/30p	21.2	11.7	200	54
8.		Olympus XZ-2	1/1.7	11.8	3968	2976	1080/30p	20.4	11.3	216	49
9.		Panasonic LF1	1/1.7	12.0	4000	3000	1080/60i	20.8	11.6	211	52
10.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
11.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
12.		Pentax K-30	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1129	79
13.		Pentax K-50	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1120	79
14.		Pentax K-500	APS-C	16.1	4928	3264	1080/30p	23.7	13.1	1087	79
15.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
16.		Sony A58	APS-C	19.8	5456	3632	1080/60i	23.3	12.5	753	74
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 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, 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 MX-1 relies on live view and the rear LCD for framing. The adjacent table lists some of the other core features of the Pentax K-S1 and Pentax MX-1 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.		Pentax K-S1	optical	n	3.0 / 921	fixed	n	1/6000s	5.4/s	Y	Y
2.		Pentax MX-1	none	n	3.0 / 920	tilting	n	1/8000s	1.0/s	Y	Y
3.		Canon G15	optical	n	3.0 / 922	fixed	n	1/4000s	2.1/s	Y	Y
4.		Canon G16	optical	n	3.0 / 922	fixed	n	1/4000s	2.2/s	Y	Y
5.		Nikon D5300	optical	n	3.2 / 1037	swivel	n	1/4000s	5.0/s	Y	n
6.		Nikon D5500	optical	n	3.2 / 1037	swivel	Y	1/4000s	5.0/s	Y	n
7.		Nikon P7800	921	n	3.0 / 921	swivel	n	1/4000s	8.0/s	Y	Y
8.		Olympus XZ-2	optional	n	3.0 / 920	tilting	Y	1/2000s	5.0/s	Y	Y
9.		Panasonic LF1	200	n	3.0 / 920	fixed	n	1/4000s	10.0/s	Y	Y
10.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
11.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
12.		Pentax K-30	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
13.		Pentax K-50	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
14.		Pentax K-500	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
15.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
16.		Sony A58	1440	n	2.7 / 460	tilting	n	1/4000s	5.0/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.

Concerning the storage of imaging data, both the K-S1 and the MX-1 write their files to SDXC cards. The K-S1 supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the MX-1 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 Pentax K-S1 and Pentax MX-1 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.		Pentax K-S1	Y	stereo / mono	-	-	micro	2.0	-	-	-
2.		Pentax MX-1	-	stereo / mono	-	-	mini	2.0	-	-	-
3.		Canon G15	Y	stereo / mono	-	-	mini	2.0	-	-	-
4.		Canon G16	Y	stereo / mono	-	-	mini	2.0	Y	-	-
5.		Nikon D5300	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
6.		Nikon D5500	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
7.		Nikon P7800	Y	stereo / mono	Y	-	mini	2.0	-	-	-
8.		Olympus XZ-2	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Panasonic LF1	-	stereo / mono	-	-	mini	2.0	Y	Y	-
10.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
11.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
12.		Pentax K-30	Y	mono / mono	-	-	-	2.0	-	-	-
13.		Pentax K-50	Y	mono / mono	-	-	micro	2.0	-	-	-
14.		Pentax K-500	Y	mono / mono	-	-	-	2.0	-	-	-
15.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
16.		Sony A58	Y	stereo / mono	Y	-	mini	2.0	-	-	-
17.		Sony A68	Y	stereo / mono	Y	-	micro	2.0	-	-	-

It is notable that the K-S1 has a hotshoe, while the MX-1 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.

Both the K-S1 and the MX-1 have been discontinued, but can regularly be found used on ebay. The K-S1 was replaced by the Pentax K-S2, while the MX-1 does not have a direct successor. Further information on the features and operation of the K-S1 and MX-1 can be found, respectively, in the Pentax K-S1 Manual (free pdf) or the online Pentax MX-1 Manual.

Review summary

So how do things add up? Which of the two cameras – the Pentax K-S1 or the Pentax MX-1 – 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 Pentax K-S1:

• More detail: Offers more megapixels (20 vs 12MP) with a 32% higher linear resolution.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (29 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (3.1 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (1.7 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (2.4 stops ISO advantage).
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Faster burst: Shoots at higher frequency (5.4 vs 1 flaps/sec) to capture the decisive moment.
• More flexible: Can take a variety of interchangeable lenses, including specialty optics.
• Longer lasting: Can take more shots (410 versus 290) on a single battery charge.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Is somewhat more recent (announced 1 year and 7 months after the MX-1).

Advantages of the Pentax MX-1:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/6000s) to freeze action.
• Ready to shoot: Comes with an integrated lens, while the K-S1 requires a separate lens.
• More compact: Is smaller (122x61mm vs 121x93mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight even though it has a lens built in (unlike the K-S1).
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More heavily discounted: Has been on the market for longer (launched in January 2013).

If the count of individual advantages (bullet points above) is taken as a guide, the K-S1 is the clear winner of the match-up (13 : 8 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 Pentax K-S1 and the Pentax MX-1 place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Travel-Zoom Camera listings 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 K-S1 or the MX-1. 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	Street Price
1.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	US$ 749	ebay.com
2.		Pentax MX-1	3/5	..	..	74/100	4/5	4/5	Jan 2013	US$ 499	ebay.com
3.		Canon G15	4/5	+	..	76/100	4.5/5	4.5/5	Sep 2012	US$ 499	ebay.com
4.		Canon G16	4/5	+	..	..	4.5/5	4.5/5	Aug 2013	US$ 549	ebay.com
5.		Nikon D5300	4/5	+ +	..	79/100	4.5/5	4.5/5	Oct 2013	US$ 799	ebay.com
6.		Nikon D5500	5/5	+	..	79/100	4.5/5	4.5/5	Jan 2015	US$ 899	ebay.com
7.		Nikon P7800	3/5	..	..	..	4/5	4.5/5	Sep 2013	US$ 549	ebay.com
8.		Olympus XZ-2	4/5	+	..	..	4.5/5	4.5/5	Sep 2012	US$ 599	ebay.com
9.		Panasonic LF1	3/5	+	..	..	4/5	4.5/5	Apr 2013	US$ 499	ebay.com
10.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	US$ 1 299	ebay.com
11.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	US$ 1 099	ebay.com
12.		Pentax K-30	4/5	..	..	78/100	4.5/5	4.5/5	May 2012	US$ 849	ebay.com
13.		Pentax K-50	5/5	..	..	..	5/5	4.5/5	Jun 2013	US$ 599	ebay.com
14.		Pentax K-500	..	..	..	..	4.5/5	4.5/5	Jun 2013	US$ 549	ebay.com
15.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	US$ 749	ebay.com
16.		Sony A58	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	US$ 599	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. 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

Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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