Pentax K-S2 vs Sony A68

The Pentax K-S2 and the Sony Alpha SLT-A68 are two digital cameras that were announced, respectively, in February 2015 and November 2015. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Pentax has a resolution of 20 megapixels, whereas the Sony provides 24 MP.

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

Headline Specifications

Pentax K-S2		Sony A68
Digital single lens reflex		Digital single lens reflex
Pentax K mount lenses		Sony A mount lenses
20 MP – APS-C sensor		24 MP – APS-C sensor
1080/30p Video		1080/60i Video
ISO 100-51,200		ISO 100-25,600
Optical viewfinder		Electronic viewfinder (1440k dots)
3.0" LCD – 921k dots		2.7" LCD – 460k dots
Swivel screen (not touch-sensitive)		Tilting screen (no touchscreen)
5.4 shutter flaps per second		8 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		not weather sealed
410 shots per battery charge		540 shots per battery charge
123 x 91 x 73 mm, 678 g		143 x 104 x 81 mm, 610 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-S2 and the Sony Alpha SLT-A68? 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-S2 and the Sony A68 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 size dimensions are rounded to the nearest millimeter.

The K-S2 can be obtained in six different colors (black, grey, pink, orange, green, white), while the A68 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 Sony A68 is notably larger (33 percent) than the Pentax K-S2. However, the A68 is markedly lighter (10 percent) than the K-S2. It is worth mentioning in this context that the K-S2 is splash and dust resistant, while the A68 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 K-S2 gets 410 shots out of its Pentax D-LI109 battery, while the A68 can take 540 images on a single charge of its Sony NP-FM500H 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-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	ebay.com
2.		Sony A68	143 mm	104 mm	81 mm	610 g	540	n	Nov 2015	699	ebay.com
3.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
4.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
5.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	1,099	ebay.com
6.		Pentax K-30	130 mm	97 mm	71 mm	650 g	410	Y	May 2012	849	ebay.com
7.		Pentax K-50	130 mm	97 mm	71 mm	650 g	410	Y	Jun 2013	599	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 A58	129 mm	95 mm	78 mm	492 g	690	n	Feb 2013	599	ebay.com
12.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
13.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	1,199	ebay.com
14.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	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

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 A68 was somewhat cheaper (by 7 percent) than the K-S2 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 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. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the background. On the downside, larger sensors are more costly to manufacture and tend to lead to bigger and heavier cameras 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.

While the two cameras under review share the same sensor size, the A68 offers a higher resolution of 24 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 A68 has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.91μm versus 4.28μm for the K-S2). However, it should be noted that the A68 is a somewhat more recent model (by 8 months) than the K-S2, and its sensor might have benefitted from technological advances during this time that at least partly compensate for the smaller pixel size. Coming back to sensor resolution, it should be mentioned that the K-S2 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Sony A68 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A68 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-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.

The Pentax K-S2 has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Sony Alpha SLT-A68 are ISO 100 to ISO 25600 (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 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-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
2.		Sony A68	APS-C	24.0	6000	4000	1080/60i	24.1	13.5	701	79
3.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
4.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
5.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
6.		Pentax K-30	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1129	79
7.		Pentax K-50	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1120	79
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 A58	APS-C	19.8	5456	3632	1080/60i	23.3	12.5	753	74
12.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
13.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
14.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	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 also of capturing video footage. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A68 provides a faster frame rate than the K-S2. It can shoot movie footage at 1080/60i, 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 A68 has an electronic viewfinder (1440k dots), while the K-S2 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 K-S2 has a higher magnification than the one of the A68 (0.63x vs 0.57x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Pentax K-S2 and Sony A68 in connection with corresponding information for a sample of similar 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-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
2.		Sony A68	1440	Y	2.7 / 460	tilting	n	1/4000s	8.0/s	Y	Y
3.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
4.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
5.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
6.		Pentax K-30	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
7.		Pentax K-50	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/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 A58	1440	n	2.7 / 460	tilting	n	1/4000s	5.0/s	Y	Y
12.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
13.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	Y	Y
14.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the A68, 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-S2 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.

The K-S2 writes its imaging data to SDXC cards, while the A68 uses SDXC or Memory Stick PRO Duo 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 Pentax K-S2 and Sony Alpha SLT-A68 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-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
2.		Sony A68	Y	stereo / mono	Y	-	micro	2.0	-	-	-
3.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
4.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
5.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
6.		Pentax K-30	Y	mono / mono	-	-	-	2.0	-	-	-
7.		Pentax K-50	Y	mono / mono	-	-	micro	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 A58	Y	stereo / mono	Y	-	mini	2.0	-	-	-
12.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
13.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
14.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-

It is notable that the K-S2 offers wifi support, while the A68 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Both the K-S2 and the A68 have been discontinued, but can regularly be found used on ebay. Neither of the two has a direct successor, so they represent the end of the respective camera lines from Pentax and Sony. Further information on the features and operation of the K-S2 and A68 can be found, respectively, in the Pentax K-S2 Manual (free pdf) or the online Sony A68 Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Pentax K-S2 or the Sony A68 – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Pentax K-S2:

• 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.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.63x vs 0.57x).
• Larger screen: Has a bigger rear LCD (3.0" vs 2.7") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 460k dots).
• 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.
• Faster shutter: Has higher mechanical shutter speed (1/6000s vs 1/4000s) to freeze action.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (123x91mm vs 143x104mm) and thus needs less room in the bag.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• 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 heavily discounted: Has been on the market for longer (launched in February 2015).

Reasons to prefer the Sony Alpha SLT-A68:

• More detail: Has more megapixels (24 vs 20MP), which boosts linear resolution by 10%.
• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better video: Provides higher movie framerates (1080/60i versus 1080/30p).
• More framing info: Has an electronic viewfinder that displays shooting data.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Faster burst: Shoots at higher frequency (8 vs 5.4 flaps/sec) to capture the decisive moment.
• Longer lasting: Gets more shots (540 versus 410) out of a single battery charge.
• More modern: Was introduced somewhat (8 months) more recently.

If the count of individual advantages (bullet points above) is taken as a guide, the K-S2 is the clear winner of the match-up (14 : 8 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision on a new camera. A professional sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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-S2 and the Sony A68 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-S2 or the A68. 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 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-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
2.		Sony A68	3/5	..	..	..	4/5	4/5	Nov 2015	699	ebay.com
3.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
4.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
5.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	1,099	ebay.com
6.		Pentax K-30	4/5	..	..	78/100	4.5/5	4.5/5	May 2012	849	ebay.com
7.		Pentax K-50	5/5	..	..	..	5/5	4.5/5	Jun 2013	599	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 A58	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	599	ebay.com
12.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
13.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	1,199	ebay.com
14.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	599	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

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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. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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