Pentax K-3 II vs K-S2

The Pentax K-3 II and the Pentax K-S2 are two digital cameras that were officially introduced, respectively, in April 2015 and February 2015. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The K-3 II has a resolution of 24.1 megapixels, whereas the K-S2 provides 20 MP.

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

Headline Specifications

Pentax K-3 II		Pentax K-S2
Digital single lens reflex		Digital single lens reflex
Pentax K mount lenses		Pentax K mount lenses
24.1 MP – APS-C sensor		20 MP – APS-C sensor
1080/60i Video		1080/30p Video
ISO 100-51,200		ISO 100-51,200
Optical viewfinder		Optical viewfinder
3.2" LCD – 1037k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Swivel screen (not touch-sensitive)
8.3 shutter flaps per second		5.4 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
720 shots per battery charge		410 shots per battery charge
131 x 100 x 77 mm, 800 g		123 x 91 x 73 mm, 678 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-3 II and the Pentax K-S2? 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-3 II and the Pentax K-S2 are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side are shown. All width, height and depth dimensions are rounded to the nearest millimeter.

The K-3 II can be obtained in two different colors (black, silver), while the K-S2 is available in six color-versions (black, grey, pink, orange, green, white).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-S2 is notably smaller (15 percent) than the Pentax K-3 II. Moreover, the K-S2 is markedly lighter (15 percent) than the K-3 II. In this context, it is worth noting that both cameras are splash and dust-proof and can, hence, be used in inclement weather conditions or harsh environments.

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 K-3 II gets 720 shots out of its Pentax D-LI90 battery, while the K-S2 can take 410 images on a single charge of its Pentax D-LI109 power pack.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
2.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	ebay.com
3.		Nikon D7200	136 mm	107 mm	76 mm	765 g	1110	Y	Mar 2015	1,199	ebay.com
4.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
5.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
6.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	1,099	ebay.com
7.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	1,099	ebay.com
8.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
9.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
10.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	749	ebay.com
11.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	1,199	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 manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The K-S2 was launched at a markedly lower price (by 32 percent) than the K-3 II, 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 sensor inside a digital camera is one of the key determinants of image quality. A large sensor will generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have richer color-depth than smaller pixels 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 and have a format factor (sometimes also referred to as "crop factor") of 1.5. Within the spectrum of camera sensors, this places the review cameras among the medium-sized sensor cameras that aim to strike a balance between image quality and portability. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

In terms of chip-set technology, the K-3 II uses a more advanced image processing engine (PRIME III) than the K-S2 (PRIME MII), with benefits for noise reduction, color accuracy, and processing speed.

While the two cameras under review share the same sensor size, the K-3 II offers a higher resolution of 24.1 megapixels, compared with 20 MP of the K-S2. This megapixels advantage translates into a 10 percent gain in linear resolution. On the other hand, these sensor specs imply that the K-3 II has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.90μm versus 4.28μm for the K-S2). It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation. Coming back to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

The resolution advantage of the Pentax K-3 II implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-3 II for good quality output (200 dots per inch) amounts to 30.1 x 20 inches or 76.4 x 50.8 cm, for very good quality (250 dpi) 24.1 x 16 inches or 61.1 x 40.6 cm, and for excellent quality (300 dpi) 20.1 x 13.3 inches or 50.9 x 33.9 cm. The corresponding values for the Pentax K-S2 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.

Unlike the K-S2, the K-3 II has the capacity to capture high quality composite images 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 Pentax K-3 II has a native sensitivity range from ISO 100 to ISO 51200. The Pentax K-S2 offers exactly the same ISO settings.

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. 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-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
2.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
3.		Nikon D7200	APS-C	24.0	6000	4000	1080/60p	24.5	14.6	1333	87
4.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
5.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
6.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
7.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
8.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
9.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
10.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
11.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
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. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the K-3 II provides a higher frame rate than the K-S2. It can shoot video footage at 1080/60i, while the K-S2 is limited to 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The K-3 II and the K-S2 are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The viewfinders of both cameras offer the same field of view (100%), as well as the same magnification (0.63x). The following table reports on some other key feature differences and similarities of the Pentax K-3 II, the Pentax K-S2, 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.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
2.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
3.		Nikon D7200	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
4.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
5.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
6.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
7.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
8.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
9.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
10.		Pentax K-S1	optical	n	3.0 / 921	fixed	n	1/6000s	5.4/s	Y	Y
11.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the K-3 II, but is missing on the K-S2 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The Pentax K-3 II and the Pentax K-S2 both have 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 K-3 II and the K-S2 write their files to SDXC cards. The K-3 II features dual card slots, which can be very useful in case a memory card fails. In contrast, the K-S2 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 Pentax K-3 II and Pentax K-S2 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-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
2.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
3.		Nikon D7200	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
4.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
5.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
6.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
7.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
8.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
9.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
10.		Pentax K-S1	Y	stereo / mono	-	-	micro	2.0	-	-	-
11.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-

It is notable that the K-3 II has a headphone jack, which is not present on the K-S2 This port makes it possible to attach external headphones and monitor the quality of sound during the recording process.

Studio photographers will appreciate that the Pentax K-3 II (unlike the K-S2) 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 II has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

Both the K-3 II and the K-S2 have been discontinued, but can regularly be found used on ebay. The K-3 II was replaced by the Pentax K-3 III, while the K-S2 does not have a direct successor. Further information on the features and operation of the K-3 II and K-S2 can be found, respectively, in the Pentax K-3 II Manual (free pdf) or the online Pentax K-S2 Manual.

Review summary

So how do things add up? Is the Pentax K-3 II better than the Pentax K-S2 or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Pentax K-3 II:

• More detail: Offers more megapixels (24.1 vs 20MP) with a 10% higher linear resolution.
• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Better jpgs: Has a more modern image processing engine (PRIME III vs PRIME MII).
• 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 setting verification: Features an LCD display on top to control 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 (1037k vs 921k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/6000s) to freeze action.
• Faster burst: Shoots at higher frequency (8.3 vs 5.4 flaps/sec) to capture the decisive moment.
• Longer lasting: Can take more shots (720 versus 410) on a single battery charge.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• 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.

Reasons to prefer the Pentax K-S2:

• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• More compact: Is smaller (123x91mm vs 131x100mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 122g or 15 percent) and is thus easier to take along.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• 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 (32 percent cheaper at launch).

If the count of relative strengths (bullet points above) is taken as a measure, the K-3 II is the clear winner of the match-up (15 : 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 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 Pentax K-3 II and the Pentax K-S2 place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing 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 remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the K-3 II or the K-S2. 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 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 (USD)	Street Price
1.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
2.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
3.		Nikon D7200	4/5	+ +	..	84/100	4.5/5	4.5/5	Mar 2015	1,199	ebay.com
4.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
5.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
6.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	1,099	ebay.com
7.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	1,099	ebay.com
8.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
9.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
10.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	749	ebay.com
11.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	1,199	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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