Pentax K-S1 vs Zeiss ZX1

The Pentax K-S1 and the Zeiss ZX1 are two digital cameras that were revealed to the public, respectively, in August 2014 and September 2018. The K-S1 is a DSLR, while the ZX1 is a fixed lens compact. The cameras are based on an APS-C (K-S1) and a full frame (ZX1) sensor. The Pentax has a resolution of 20 megapixels, whereas the Zeiss provides 37.4 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		Zeiss ZX1
Digital single lens reflex		Fixed lens compact camera
Pentax K mount lenses		35mm f/2.8
20 MP – APS-C sensor		37.4 MP – Full Frame sensor
1080/30p Video		4K/30p Video
ISO 100-51,200		ISO 80-51,200
Optical viewfinder		Electronic viewfinder (6221k dots)
3.0" LCD – 921k dots		4.3" LCD – 2765k dots
Fixed screen (not touch-sensitive)		Fixed touchscreen
5.4 shutter flaps per second		3 shutter flaps per second
In-body stabilization		no shake reduction
410 shots per battery charge		250 shots per battery charge
121 x 93 x 70 mm, 558 g		142 x 93 x 46 mm, 800 g

Check K-S1 offers at
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Check ZX1 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 Zeiss ZX1? 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 Pentax K-S1 and the Zeiss ZX1 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 width, height and depth dimensions are rounded to the nearest millimeter.

The K-S1 can be obtained in four different colors (black, grey, orange, white), while the ZX1 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 Zeiss ZX1 is notably larger (17 percent) than the Pentax K-S1. In this context, it is worth noting that neither the K-S1 nor the ZX1 are weather-sealed.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the ZX1 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.

Concerning battery life, the K-S1 gets 410 shots out of its Pentax D-LI109 battery, while the ZX1 can take 250 images on a single charge of its Zeiss DD-PS1A power pack.

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 (USD)	Street Price
1.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	749	ebay.com
2.		Zeiss ZX1	142 mm	93 mm	46 mm	800 g	250	n	Sep 2018	5,999	ebay.com
3.		Leica Q2	130 mm	80 mm	92 mm	718 g	370	Y	Mar 2019	4,995	amazon.com
4.		Leica M10	139 mm	80 mm	39 mm	660 g	210	Y	Jan 2017	6,595	ebay.com
5.		Leica Q Typ 116	130 mm	80 mm	93 mm	640 g	300	n	Jun 2015	4,249	ebay.com
6.		Nikon D5500	124 mm	97 mm	70 mm	470 g	820	n	Jan 2015	899	ebay.com
7.		Nikon D5300	125 mm	98 mm	76 mm	480 g	600	n	Oct 2013	799	ebay.com
8.		Panasonic FZ1000	137 mm	99 mm	131 mm	831 g	360	n	Jun 2014	899	ebay.com
9.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	ebay.com
10.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
11.		Pentax K-50	130 mm	97 mm	71 mm	650 g	410	Y	Jun 2013	599	ebay.com
12.		Pentax K-500	130 mm	97 mm	71 mm	646 g	710	n	Jun 2013	549	ebay.com
13.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
14.		Pentax K-30	130 mm	97 mm	71 mm	650 g	410	Y	May 2012	849	ebay.com
15.		Sony RX1R II	113 mm	65 mm	72 mm	507 g	220	n	Oct 2015	3,299	ebay.com
16.		Sony A68	143 mm	104 mm	81 mm	610 g	540	n	Nov 2015	699	ebay.com
17.		Sony A58	129 mm	95 mm	78 mm	492 g	690	n	Feb 2013	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

Any camera decision will naturally be influenced heavily by the price. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. 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. 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.

Of the two cameras under consideration, the Pentax K-S1 features an APS-C sensor and the Zeiss ZX1 a full frame sensor. The sensor area in the ZX1 is 135 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 37.4MP, the ZX1 offers a higher resolution than the K-S1 (20MP), but the ZX1 nevertheless has larger individual pixels (pixel pitch of 4.81μm versus 4.28μm for the K-S1) due to its larger sensor. Moreover, the ZX1 is a much more recent model (by 4 years and 1 month) than the K-S1, 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-S1 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Zeiss ZX1 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the ZX1 for good quality output (200 dots per inch) amounts to 37.4 x 25 inches or 95.1 x 63.4 cm, for very good quality (250 dpi) 30 x 20 inches or 76.1 x 50.7 cm, and for excellent quality (300 dpi) 25 x 16.6 inches or 63.4 x 42.3 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 Pentax K-S1 has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Zeiss ZX1 are ISO 80 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.

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 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.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
2.		Zeiss ZX1	Full Frame	37.4	7488	4992	4K/30p	25.2	14.1	2759	94
3.		Leica Q2	Full Frame	46.7	8368	5584	4K/30p	26.4	13.5	2491	96
4.		Leica M10	Full Frame	23.8	5952	3992	none	24.4	13.2	2133	86
5.		Leica Q Typ 116	Full Frame	24.0	6000	4000	1080/60p	24.3	12.7	2221	85
6.		Nikon D5500	APS-C	24.0	6000	4000	1080/60p	24.1	14.0	1438	84
7.		Nikon D5300	APS-C	24.0	6000	4000	1080/60p	24.0	13.9	1338	83
8.		Panasonic FZ1000	1-inch	20.0	5472	3648	4K/30p	22.1	11.7	517	64
9.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
10.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
11.		Pentax K-50	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1120	79
12.		Pentax K-500	APS-C	16.1	4928	3264	1080/30p	23.7	13.1	1087	79
13.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
14.		Pentax K-30	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1129	79
15.		Sony RX1R II	Full Frame	42.2	7952	5304	1080/60p	25.8	13.9	3204	97
16.		Sony A68	APS-C	24.0	6000	4000	1080/60i	24.1	13.5	701	79
17.		Sony A58	APS-C	19.8	5456	3632	1080/60i	23.3	12.5	753	74
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, but the ZX1 provides a better video resolution than the K-S1. It can shoot movie footage at 4K/30p, while the Pentax 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 ZX1 has an electronic viewfinder (6221k dots), while the K-S1 has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the ZX1 has a higher magnification than the one of the K-S1 (0.74x vs 0.63x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Pentax K-S1 and Zeiss ZX1 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.		Zeiss ZX1	6221	n	4.3 / 2765	fixed	Y	1/1000s	3.0/s	n	n
3.		Leica Q2	3680	n	3.0 / 1040	fixed	Y	1/2000s	10.0/s	n	Y
4.		Leica M10	optical	n	3.0 / 1037	fixed	n	1/4000s	5.0/s	n	n
5.		Leica Q Typ 116	3680	n	3.0 / 1040	fixed	Y	1/2000s	10.0/s	n	Y
6.		Nikon D5500	optical	n	3.2 / 1037	swivel	Y	1/4000s	5.0/s	Y	n
7.		Nikon D5300	optical	n	3.2 / 1037	swivel	n	1/4000s	5.0/s	Y	n
8.		Panasonic FZ1000	2359	n	3.0 / 921	swivel	n	1/4000s	12.0/s	Y	Y
9.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
10.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
11.		Pentax K-50	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
12.		Pentax K-500	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
13.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
14.		Pentax K-30	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
15.		Sony RX1R II	2360	n	3.0 / 1229	tilting	n	1/4000s	5.0/s	n	n
16.		Sony A68	1440	Y	2.7 / 460	tilting	n	1/4000s	8.0/s	Y	Y
17.		Sony A58	1440	n	2.7 / 460	tilting	n	1/4000s	5.0/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 K-S1 has one, while the ZX1 does not. While the built-in flash of the K-S1 is not very powerful, it can at times be useful as a fill-in light.

The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the ZX1 is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).

The K-S1 writes its imaging data to SDXC cards, while the ZX1 uses an internal SSD.

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 Zeiss ZX1 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.		Zeiss ZX1	Y	stereo / mono	-	-	-	3.1	Y	Y	Y
3.		Leica Q2	Y	stereo / mono	-	-	-	-	Y	-	Y
4.		Leica M10	Y	- / -	-	-	-	-	Y	-	-
5.		Leica Q Typ 116	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
6.		Nikon D5500	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
7.		Nikon D5300	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
8.		Panasonic FZ1000	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
9.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
10.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
11.		Pentax K-50	Y	mono / mono	-	-	micro	2.0	-	-	-
12.		Pentax K-500	Y	mono / mono	-	-	-	2.0	-	-	-
13.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
14.		Pentax K-30	Y	mono / mono	-	-	-	2.0	-	-	-
15.		Sony RX1R II	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
16.		Sony A68	Y	stereo / mono	Y	-	micro	2.0	-	-	-
17.		Sony A58	Y	stereo / mono	Y	-	mini	2.0	-	-	-

It is notable that the ZX1 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the K-S1 does not provide wifi capability.

Both the K-S1 and the ZX1 have been discontinued, but can regularly be found used on ebay. The K-S1 was replaced by the Pentax K-S2, while the ZX1 does not have a direct successor. Further information on the features and operation of the K-S1 and ZX1 can be found, respectively, in the Pentax K-S1 Manual (free pdf) or the online Zeiss ZX1 Manual.

Review summary

So how do things add up? Is there a clear favorite between the Pentax K-S1 and the Zeiss ZX1? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Pentax K-S1:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Faster shutter: Has higher mechanical shutter speed (1/6000s vs 1/1000s) to freeze action.
• Faster burst: Shoots at higher frequency (5.4 vs 3 flaps/sec) to capture the decisive moment.
• More flexible: Can take a variety of interchangeable lenses, including specialty optics.
• More compact: Is smaller (121x93mm vs 142x93mm) and thus needs less room in the bag.
• Longer lasting: Can take more shots (410 versus 250) on a single battery charge.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More heavily discounted: Has been available for much longer (launched in August 2014).

Advantages of the Zeiss ZX1:

• More detail: Has more megapixels (37.4 vs 20MP), which boosts linear resolution by 37%.
• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better image quality: Is equipped with a larger and more technologically advanced sensor.
• Richer colors: The sensor size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger sensor captures a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger sensor produces good images even in poorly lit environments.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/30p).
• More framing info: Has an electronic viewfinder that displays shooting data.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.74x vs 0.63x).
• Larger screen: Has a bigger rear LCD (4.3" vs 3.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (2765k vs 921k dots).
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Ready to shoot: Comes with an integrated lens, while the K-S1 requires a separate lens.
• Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
• 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.
• More prestigious: Has the Zeiss luxury appeal, which ensures a high resale value.
• More modern: Reflects 4 years and 1 month of technical progress since the K-S1 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the ZX1 is the clear winner of the contest (20 : 10 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. 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 Zeiss ZX1 place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Prime Lens Compact 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 incomplete and does no justice, for example, to the way the K-S1 or the ZX1 perform in practice. 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 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.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	749	ebay.com
2.		Zeiss ZX1	3/5	..	..	83/100	4/5	4/5	Sep 2018	5,999	ebay.com
3.		Leica Q2	..	..	4.5/5	84/100	4.5/5	4/5	Mar 2019	4,995	amazon.com
4.		Leica M10	4.5/5	..	..	..	4/5	4.5/5	Jan 2017	6,595	ebay.com
5.		Leica Q Typ 116	5/5	..	..	80/100	4.5/5	4.5/5	Jun 2015	4,249	ebay.com
6.		Nikon D5500	5/5	+	..	79/100	4.5/5	4.5/5	Jan 2015	899	ebay.com
7.		Nikon D5300	4/5	+ +	..	79/100	4.5/5	4.5/5	Oct 2013	799	ebay.com
8.		Panasonic FZ1000	4/5	+ +	..	82/100	4.5/5	4.5/5	Jun 2014	899	ebay.com
9.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
10.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
11.		Pentax K-50	5/5	..	..	..	5/5	4.5/5	Jun 2013	599	ebay.com
12.		Pentax K-500	..	..	..	..	4.5/5	4.5/5	Jun 2013	549	ebay.com
13.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
14.		Pentax K-30	4/5	..	..	78/100	4.5/5	4.5/5	May 2012	849	ebay.com
15.		Sony RX1R II	5/5	..	..	82/100	..	4.5/5	Oct 2015	3,299	ebay.com
16.		Sony A68	3/5	..	..	..	4/5	4/5	Nov 2015	699	ebay.com
17.		Sony A58	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	599	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. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. 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? If you would like to see a different side-by-side camera review, just use the search menu below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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