Pentax KP vs Sony A7S III
The Pentax KP and the Sony Alpha 7S III are two digital cameras that were revealed to the public, respectively, in January 2017 and July 2020. The KP is a DSLR, while the A7S III is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (KP) and a full frame (A7S III) 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.
Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax KP and the Sony Alpha 7S III? 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.
An illustration of the physical size and weight of the Pentax KP and the Sony A7S III is provided 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 KP can be obtained in two different colors (black, silver), while the A7S III 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 III is notably smaller (8 percent) than the Pentax KP. Moreover, the A7S III is slightly lighter (1 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 III can take 600 images on a single charge of its NP-FZ100 power pack. The power pack in the A7S III can be charged via the USB port, which can be very convenient when travelling.
The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.
|1.||Pentax KP||132 mm||101 mm||76 mm||703 g||390||Y||Jan 2017||1,099|
|2.||Sony A7S III||127 mm||97 mm||81 mm||699 g||600||Y||Jul 2020||3,499|
|3.||Fujifilm X-H1||140 mm||97 mm||86 mm||673 g||310||Y||Feb 2018||1,899|
|4.||Nikon D7500||136 mm||104 mm||73 mm||720 g||950||Y||Apr 2017||1,299|
|5.||Pentax K-3 III||135 mm||104 mm||74 mm||820 g||800||Y||Mar 2021||1,999|
|6.||Pentax K-70||126 mm||93 mm||74 mm||688 g||410||Y||Jun 2016||649|
|7.||Pentax K-S2||123 mm||91 mm||73 mm||678 g||410||Y||Feb 2015||749|
|8.||Pentax K-3 II||131 mm||100 mm||77 mm||800 g||720||Y||Apr 2015||1,099|
|9.||Pentax K-3||131 mm||100 mm||77 mm||800 g||560||Y||Oct 2013||1,299|
|10.||Pentax K-5 II||131 mm||97 mm||73 mm||760 g||740||Y||Sep 2012||1,099|
|11.||Pentax K-5||131 mm||97 mm||73 mm||760 g||740||Y||Sep 2010||1,099|
|12.||Sony A7R IV||129 mm||96 mm||78 mm||665 g||670||Y||Jul 2019||3,499|
|13.||Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199|
|14.||Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|15.||Sony A7R II||127 mm||96 mm||60 mm||625 g||290||Y||Jun 2015||3,199|
|16.||Sony A7S II||127 mm||96 mm||60 mm||627 g||370||Y||Sep 2015||2,999|
|17.||Sony A77 II||143 mm||104 mm||81 mm||647 g||480||Y||May 2014||1,199|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
The price is, of course, an important factor in any camera decision. 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 KP was launched at a markedly lower price (by 69 percent) than the A7S III, 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.
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. 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 KP features an APS-C sensor and the Sony A7S III a full frame sensor. The sensor area in the A7S III is 131 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 III. 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 8.40μm for the A7S III). Moreover, it should be noted that the A7S III is much more recent (by 3 years and 6 months) than the KP, 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 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 III 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 III, 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 7S III are ISO 80 to ISO 102400, with the possibility to increase the ISO range to 40-409600.
For many cameras, data on sensor performance has been reported by DXO Mark. 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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
| DXO |
|2.||Sony A7S III||Full Frame||12.0||4240||2832||4K/120p||23.7||13.9||2520||86|
|5.||Pentax K-3 III||APS-C||25.6||6192||4128||4K/30p||..||..||..||..|
|8.||Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
|10.||Pentax K-5 II||APS-C||16.1||4928||3264||1080/25p||23.8||14.1||1235||82|
|12.||Sony A7R IV||Full Frame||60.2||9504||6336||4K/30p||26.0||14.8||3344||99|
|13.||Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|14.||Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|15.||Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|16.||Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
|17.||Sony A77 II||APS-C||24.0||6000||4000||1080/60p||..||..||..||..|
Many modern cameras cannot only take still pictures, but also record videos. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A7S III provides a better video resolution than the KP. It can shoot movie footage at 4K/120p, while the Pentax is limited to 1080/60i.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the A7S III has an electronic viewfinder (9440k 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 III has a higher magnification than the one of the KP (0.91x vs 0.63x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The following table reports on some other key feature differences and similarities of the Pentax KP, the Sony A7S III, and comparable cameras.
|2.||Sony A7S III||9440||n||3.0||1440||swivel||Y||1/8000s||10.0||n||Y|
|5.||Pentax K-3 III||optical||Y||3.2||1620||fixed||Y||1/8000s||12.0||n||Y|
|8.||Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y|
|10.||Pentax K-5 II||optical||Y||3.0||921||fixed||n||1/8000s||7.0||Y||Y|
|12.||Sony A7R IV||5760||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|13.||Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|15.||Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|16.||Sony A7S II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|17.||Sony A77 II||2359||Y||3.0||1229||full-flex||n||1/8000s||12.0||Y||Y|
One difference between the cameras concerns the presence of an on-board flash. The KP has one, while the A7S III 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 A7S III has an articulated screen that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in taking selfies. In contrast, the KP does not have a selfie-screen.
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 III uses CFexpress or SDXC cards. The A7S III features dual card slots, which can be very useful in case a memory card fails. In contrast, the KP only has one slot. The A7S III supports UHS-II cards (on both slots), while the KP can use UHS-I cards.
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 7S III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|2.||Sony A7S III||Y||stereo||mono||Y||Y||full||3.2||Y||-||Y|
|5.||Pentax K-3 III||Y||stereo||mono||Y||Y||micro||3.2||Y||-||Y|
|8.||Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
|10.||Pentax K-5 II||Y||stereo||mono||Y||-||mini||2.0||-||-||-|
|12.||Sony A7R IV||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|13.||Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|15.||Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|16.||Sony A7S II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|17.||Sony A77 II||Y||stereo||mono||Y||-||mini||2.0||Y||Y||-|
It is notable that the A7S III 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 III are recent models that are part of the current product line-up. The A7S III replaced the earlier Sony A7S II, while the KP does not have a direct predecessor. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Pentax and Sony websites.
So how do things add up? Is the Pentax KP better than the Sony A7S III or vice versa? The listing below highlights the relative strengths of the two models.
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.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- More affordable: Was introduced into a lower priced category (69 percent cheaper at launch).
- More heavily discounted: Has been available for much longer (launched in January 2017).
Arguments in favor of the Sony Alpha 7S III:
- 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/120p vs 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 (0.91x vs 0.63x).
- More detailed LCD: Has a higher resolution rear screen (1440k vs 921k dots).
- More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/6000s) to freeze action.
- Faster burst: Shoots at higher frequency (10 vs 7 flaps/sec) to capture the decisive moment.
- Longer lasting: Gets more shots (600 versus 390) out of a single battery charge.
- Easier travel charging: Can be conveniently charged via its USB port.
- More legacy lens friendly: Can use many non-native lenses via adapters.
- Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
- More solid recording: Has a full-sized HDMI port for a sturdy connection to an external recorder.
- Easier wireless transfer: Supports Bluetooth for image sharing without cables.
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- More modern: Reflects 3 years and 6 months of technical progress since the KP launch.
If the count of relative strengths (bullet points above) is taken as a measure, the A7S III is the clear winner of the contest (24 : 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 KP and the Sony A7S III 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 remains incomplete and does no justice, for example, to the way the KP or the A7S III perform in practice. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable.
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], 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.
|1.||Pentax KP||4/5||..||82/100||5/5||4.5/5||Jan 2017||1,099|
|2.||Sony A7S III||..||+ +||91/100||4.5/5||5/5||Jul 2020||3,499|
|3.||Fujifilm X-H1||..||+||86/100||4.5/5||4.5/5||Feb 2018||1,899|
|4.||Nikon D7500||4.5/5||+ +||86/100||5/5||4.5/5||Apr 2017||1,299|
|5.||Pentax K-3 III||..||..||..||..||..||Mar 2021||1,999|
|6.||Pentax K-70||4.5/5||..||79/100||4.5/5||4.5/5||Jun 2016||649|
|7.||Pentax K-S2||4.5/5||..||..||5/5||4.5/5||Feb 2015||749|
|8.||Pentax K-3 II||4.5/5||..||..||5/5||5/5||Apr 2015||1,099|
|9.||Pentax K-3||4/5||..||83/100||5/5||5/5||Oct 2013||1,299|
|10.||Pentax K-5 II||5/5||..||80/100||5/5||4.5/5||Sep 2012||1,099|
|11.||Pentax K-5||4/5||..||83/100||5/5||4.5/5||Sep 2010||1,099|
|12.||Sony A7R IV||5/5||+||91/100||4.5/5||5/5||Jul 2019||3,499|
|13.||Sony A7R III||..||+ +||90/100||4.5/5||5/5||Oct 2017||3,199|
|14.||Sony A9||5/5||+ +||89/100||5/5||5/5||Apr 2017||4,499|
|15.||Sony A7R II||5/5||+ +||90/100||5/5||5/5||Jun 2015||3,199|
|16.||Sony A7S II||5/5||+||..||4.5/5||5/5||Sep 2015||2,999|
|17.||Sony A77 II||4/5||..||80/100||4.5/5||5/5||May 2014||1,199|
|Notes: (+ +) 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 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.
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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.
Specifications: Pentax KP vs Sony A7S III
Below is a side-by-side comparison of the specs of the two cameras to facilitate a quick review of their differences and common features.
|Camera Model||Pentax KP||Sony A7S III|
|Camera Type||Digital single lens reflex||Mirrorless system camera|
|Camera Lens||Pentax K mount lenses||Sony E mount lenses|
|Launch Date||January 2017||July 2020|
|Launch Price||USD 1,099||USD 3,499|
|Sensor Specs||Pentax KP||Sony A7S III|
|Sensor Format||APS-C Sensor||Full Frame Sensor|
|Sensor Size||23.5 x 15.6 mm||35.6 x 23.8 mm|
|Sensor Area||366.6 mm2||847.28 mm2|
|Sensor Diagonal||28.2 mm||42.8 mm|
|Sensor Resolution||24.1 Megapixels||12 Megapixels|
|Image Resolution||6016 x 4000 pixels||4240 x 2832 pixels|
|Pixel Pitch||3.90 μm||8.40 μm|
|Pixel Density||6.56 MP/cm2||1.42 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||1080/60i Video||4K/120p Video|
|ISO Setting||100 - 819,200 ISO||80 - 102,400 ISO|
|ISO Boost||no Enhancement||40 - 409,600 ISO|
|Image Processor||PRIME IV||BIONZ XR|
|DXO Sensor Quality (score)||..||86|
|DXO Color Depth (bits)||..||23.7|
|DXO Dynamic Range (EV)||..||13.9|
|DXO Low Light (ISO)||..||2520|
|Screen Specs||Pentax KP||Sony A7S III|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||9440k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||921k dots||1440k dots|
|LCD Attachment||Tilting screen||Swivel screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Pentax KP||Sony A7S III|
|Focus System||Phase-detect AF||Contrast-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/6000s||1/8000s|
|Continuous Shooting||7 shutter flaps/s||10 shutter flaps/s|
|Shutter Life Expectancy||100 000 actuations||200 000 actuations|
|Electronic Shutter||up to 1/24000s||YES|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||CFexpress or SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||UHS-I||Dual UHS-II|
|Connectivity Specs||Pentax KP||Sony A7S III|
|USB Connector||USB 2.0||USB 3.2|
|HDMI Port||no HDMI||full HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||no Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Bluetooth Support||no Bluetooth||Bluetooth built-in|
|Body Specs||Pentax KP||Sony A7S III|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||390 shots per charge||600 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
132 x 101 x 76 mm
(5.2 x 4.0 x 3.0 in)
127 x 97 x 81 mm
(5.0 x 3.8 x 3.2 in)
|Camera Weight||703 g (24.8 oz)||699 g (24.7 oz)|
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