Pentax KP vs Sony A7S

The Pentax KP and the Sony Alpha A7S are two digital cameras that were revealed to the public, respectively, in January 2017 and April 2014. The KP is a DSLR, while the A7S is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (KP) and a full frame (A7S) sensor. The Pentax has a resolution of 24.1 megapixels, whereas the Sony 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 KP		Sony A7S
Digital single lens reflex		Mirrorless system camera
Pentax K mount lenses		Sony E mount lenses
24.1 MP – APS-C sensor		12 MP – Full Frame sensor
1080/60i Video		1080/60p Video
ISO 100-819,200		ISO 100-102,400 (50 - 409,600)
Optical viewfinder		Electronic viewfinder (2400k dots)
3.0" LCD – 921k dots		3.0" LCD – 921k dots
Tilting screen (no touchscreen)		Tilting screen (no touchscreen)
7 shutter flaps per second		5 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		Weathersealed body
390 shots per battery charge		380 shots per battery charge
132 x 101 x 76 mm, 703 g		127 x 94 x 48 mm, 489 g

Check KP offers at
ebay.com
Check A7S offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax KP and the Sony Alpha A7S? 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 side-by-side display below illustrates the physical size and weight of the Pentax KP and the Sony A7S. 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 measures are rounded to the nearest millimeter.

The KP can be obtained in two different colors (black, silver), while the A7S 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 A7S is notably smaller (10 percent) than the Pentax KP. Moreover, the A7S is markedly lighter (30 percent) than the KP. 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 KP gets 390 shots out of its D-LI109 battery, while the A7S can take 380 images on a single charge of its NP-FW50 power pack. The power pack in the A7S can be charged via the USB port, which can be very convenient when travelling.

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.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
2.		Sony A7S	127 mm	94 mm	48 mm	489 g	380	Y	Apr 2014	2,499	ebay.com
3.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	1,899	ebay.com
4.		Nikon D7500	136 mm	104 mm	73 mm	720 g	950	Y	Apr 2017	1,299	amazon.com
5.		Nikon Df	144 mm	110 mm	67 mm	760 g	1400	Y	Nov 2013	2,749	ebay.com
6.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
7.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	amazon.com
8.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	ebay.com
9.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
10.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
11.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	1,099	ebay.com
12.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	1,099	ebay.com
13.		Sony ZV-E1	121 mm	72 mm	54 mm	483 g	570	Y	Mar 2023	2,199	amazon.com
14.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
15.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	1,199	ebay.com
16.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	1,699	ebay.com
17.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	2,299	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. The KP was launched at a markedly lower price (by 56 percent) than the A7S, which puts it into a different market segment. 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 size of the imaging sensor is a crucial determinant 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 more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Pentax KP features an APS-C sensor and the Sony A7S a full frame sensor. The sensor area in the A7S is 133 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.

Despite having a smaller sensor, the Pentax KP offers a higher resolution of 24.1 megapixels, compared with 12 MP of the Sony A7S. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.90μm versus 8.45μm for the A7S). However, it should be noted that the KP is much more recent (by 2 years and 9 months) than the A7S, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. Coming back to sensor resolution, it should be mentioned that the KP has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax KP implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the KP 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 Sony A7S are 21.2 x 14.2 inches or 53.8 x 36 cm for good quality, 17 x 11.3 inches or 43.1 x 28.8 cm for very good quality, and 14.1 x 9.4 inches or 35.9 x 24 cm for excellent quality prints.

Unlike the A7S, the KP 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 KP has a native sensitivity range from ISO 100 to ISO 819200. The corresponding ISO settings for the Sony Alpha A7S are ISO 100 to ISO 102400, with the possibility to increase the ISO range to 50-409600.

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 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"). The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
2.		Sony A7S	Full Frame	12.0	4240	2832	1080/60p	23.9	13.2	3702	87
3.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
4.		Nikon D7500	APS-C	20.7	5568	3712	4K/30p	24.3	14.0	1483	86
5.		Nikon Df	Full Frame	16.2	4928	3280	none	24.6	13.1	3279	89
6.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
7.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
8.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
9.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
10.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
11.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
12.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
13.		Sony ZV-E1	Full Frame	12.0	4240	2832	4K/60p	25.4	14.6	3181	96
14.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
15.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
16.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90
17.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95
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 A7S provides a faster frame rate than the KP. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A7S has an electronic viewfinder (2400k dots), while the KP 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 A7S has a higher magnification than the one of the KP (0.71x vs 0.63x), 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 KP and Sony A7S 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 KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
2.		Sony A7S	2400	n	3.0 / 921	tilting	n	1/8000s	5.0/s	n	n
3.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
4.		Nikon D7500	optical	Y	3.2 / 922	tilting	Y	1/8000s	8.0/s	Y	n
5.		Nikon Df	optical	Y	3.2 / 921	fixed	n	1/4000s	5.5/s	n	n
6.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
7.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
8.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
9.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
10.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
11.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
12.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
13.		Sony ZV-E1	none	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
14.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
15.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	Y	Y
16.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
17.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
Notes: *) 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 KP has one, while the A7S does not. While the built-in flash of the KP 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, both cameras under consideration feature an 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 Pentax KP 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 KP writes its imaging data to SDXC cards, while the A7S 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 KP and Sony Alpha A7S 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 KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
2.		Sony A7S	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
3.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
4.		Nikon D7500	Y	stereo / mono	Y	Y	mini	2.0	Y	-	Y
5.		Nikon Df	Y	- / -	-	-	mini	2.0	-	-	-
6.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
7.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
8.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
9.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
10.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
11.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
12.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
13.		Sony ZV-E1	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
14.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
16.		Sony A7	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-

It is notable that the A7S has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The KP lacks such a headphone port.

Both the KP and the A7S have been discontinued, but can regularly be found used on ebay. The A7S was replaced by the Sony A7S II, while the KP does not have a direct successor. Further information on the features and operation of the KP and A7S can be found, respectively, in the Pentax KP Manual (free pdf) or the online Sony A7S Manual.

Review summary

So what conclusions can be drawn? Is the Pentax KP better than the Sony A7S or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Pentax KP:

• More detail: Offers more megapixels (24.1 vs 12MP) with a 42% higher linear resolution.
• 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.
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Faster burst: Shoots at higher frequency (7 vs 5 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• 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 affordable: Was introduced into a lower priced category (56 percent cheaper at launch).
• More modern: Reflects 2 years and 9 months of technical progress since the A7S launch.

Advantages of the Sony Alpha A7S:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better image quality: Features bigger pixels on a larger sensor for higher quality imaging.
• Richer colors: The pixel size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger pixels capture a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger pixels means good image quality even under poor lighting.
• Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• More framing info: Has an electronic viewfinder that displays shooting data.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.71x vs 0.63x).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/6000s) to freeze action.
• More compact: Is smaller (127x94mm vs 132x101mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 214g or 30 percent) and is thus easier to take along.
• Easier travel charging: Can be conveniently charged via its USB port.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More heavily discounted: Has been around for much longer (launched in April 2014).

If the count of relative strengths (bullet points above) is taken as a measure, the A7S is the clear winner of the contest (16 : 10 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 KP and the Sony A7S place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens 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 says little about, for example, the shooting experience and imaging performance of the KP and the A7S 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.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
2.		Sony A7S	4/5	..	..	86/100	4.5/5	5/5	Apr 2014	2,499	ebay.com
3.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	1,899	ebay.com
4.		Nikon D7500	4.5/5	+ +	4.5/5	86/100	5/5	4.5/5	Apr 2017	1,299	amazon.com
5.		Nikon Df	4/5	..	..	81/100	4/5	4/5	Nov 2013	2,749	ebay.com
6.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
7.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	amazon.com
8.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
9.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
10.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
11.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	1,099	ebay.com
12.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	1,099	ebay.com
13.		Sony ZV-E1	..	..	..	..	..	..	Mar 2023	2,199	amazon.com
14.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
15.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	1,199	ebay.com
16.		Sony A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	1,699	ebay.com
17.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	2,299	ebay.com
Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The assessments were made in relation to similar cameras of the same technological generation. A score, therefore, has to be seen in close connection to the price and market introduction time 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. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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