Pentax K-70 vs Sony A7R III
The Pentax K-70 and the Sony Alpha A7R III are two digital cameras that were officially introduced, respectively, in June 2016 and October 2017. The K-70 is a DSLR, while the A7R III is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (K-70) and a full frame (A7R III) sensor. The Pentax has a resolution of 24 megapixels, whereas the Sony provides 42.2 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 K-70 and the Sony Alpha A7R 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.
The physical size and weight of the Pentax K-70 and the Sony A7R III 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 measures are rounded to the nearest millimeter.
The K-70 can be obtained in two different colors (black, silver), while the A7R 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 A7R III is somewhat larger (4 percent) than the Pentax K-70. However, the A7R III is markedly lighter (6 percent) than the K-70. 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-70 gets 410 shots out of its D-LI109 battery, while the A7R III can take 650 images on a single charge of its NP-FZ100 power pack. The power pack in the A7R III can be charged via the USB port, which can be very convenient when travelling.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.
|Pentax K-70||5.0 in||3.7 in||2.9 in||24.3 oz||410||Y||Jun 2016||649|
|Sony A7R III||5.0 in||3.8 in||2.9 in||22.9 oz||650||Y||Oct 2017||3,199|
|Nikon Z7||5.3 in||4.0 in||2.6 in||23.8 oz||330||Y||Aug 2018||3,399|
|Olympus E-M1 II||5.3 in||3.6 in||2.6 in||20.2 oz||440||Y||Sep 2016||1,999|
|Panasonic G9||5.4 in||3.8 in||3.6 in||23.2 oz||400||Y||Nov 2017||1,699|
|Panasonic GH5||5.5 in||3.9 in||3.4 in||25.6 oz||410||Y||Jan 2017||1,999|
|Pentax KP||5.2 in||4.0 in||3.0 in||24.8 oz||390||Y||Jan 2017||1,099|
|Pentax K-3 II||5.2 in||3.9 in||3.0 in||28.2 oz||720||Y||Apr 2015||1,099|
|Pentax K-3||5.2 in||3.9 in||3.0 in||28.2 oz||560||Y||Oct 2013||1,299|
|Pentax K-5||5.2 in||3.8 in||2.9 in||26.8 oz||740||Y||Sep 2010||1,099|
|Sony A9||5.0 in||3.8 in||2.5 in||23.7 oz||650||Y||Apr 2017||4,499|
|Sony A99 II||5.6 in||4.1 in||3.0 in||29.9 oz||490||Y||Sep 2016||3,199|
|Sony A6500||4.7 in||2.6 in||2.1 in||16.0 oz||350||Y||Oct 2016||1,399|
|Sony A7R II||5.0 in||3.8 in||2.4 in||22.0 oz||290||Y||Jun 2015||3,199|
|Sony A7S II||5.0 in||3.8 in||2.4 in||22.1 oz||370||Y||Sep 2015||2,999|
|Sony A68||5.6 in||4.1 in||3.2 in||21.5 oz||540||n||Nov 2015||699|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will obviously take relative prices into account. 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 K-70 was launched at a markedly lower price (by 80 percent) than the A7R 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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. 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.
Of the two cameras under consideration, the Pentax K-70 features an APS-C sensor and the Sony A7R III a full frame sensor. The sensor area in the A7R III 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 42.2MP, the A7R III offers a higher resolution than the K-70 (24MP), but the A7R III nevertheless has larger individual pixels (pixel pitch of 4.52μm versus 3.91μm for the K-70) due to its larger sensor. Moreover, the A7R III is a somewhat more recent model (by 1 year and 4 months) than the K-70, and its sensor might 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 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 Sony A7R III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7R III for good quality output (200 dots per inch) amounts to 39.8 x 26.5 inches or 101 x 67.4 cm, for very good quality (250 dpi) 31.8 x 21.2 inches or 80.8 x 53.9 cm, and for excellent quality (300 dpi) 26.5 x 17.7 inches or 67.3 x 44.9 cm. The corresponding values for the Pentax K-70 are 30 x 20 inches or 76.2 x 50.8 cm for good quality, 24 x 16 inches or 61 x 40.6 cm for very good quality, and 20 x 13.3 inches or 50.8 x 33.9 cm for excellent quality prints.
Both cameras have the capacity to capture high quality composite images by combining multiple shots after shifting the sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).
The Pentax K-70 has a native sensitivity range from ISO 100 to ISO 102400. The corresponding ISO settings for the Sony Alpha A7R III are ISO 100 to ISO 32000, with the possibility to increase the ISO range to 50-102400.
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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
| DXO |
|Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|Nikon Z7||Full Frame||45.4||8256||5504||4K/30p||26.3||14.6||2668||99|
|Olympus E-M1 II||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|Panasonic G9||Four Thirds||20.2||5184||3888||4K/60p||..||..||..||..|
|Panasonic GH5||Four Thirds||20.2||5184||3888||4K/60p||23.9||13.0||807||77|
|Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
|Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|Sony A99 II||Full Frame||42.2||7952||5304||4K/30p||25.4||13.4||2317||92|
|Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
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 A7R III provides a better video resolution than the K-70. It can shoot movie footage at 4K/30p, while the Pentax is limited to 1080/60i.
Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A7R III has an electronic viewfinder (3686k dots), while the K-70 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 A7R III has a higher magnification than the one of the K-70 (0.78x 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 K-70 and Sony A7R III in connection with corresponding information for a sample of similar cameras.
|Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|Olympus E-M1 II||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y|
|Sony A99 II||2400||Y||3.0||1229||full-flex||n||1/8000s||12.0||n||Y|
|Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|Sony A7S II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
One difference between the cameras concerns the presence of an on-board flash. The K-70 has one, while the A7R III does not. While the built-in flash of the K-70 is not very powerful, it can at times be useful as a fill-in light.The K-70 has an articulated LCD that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in snapping selfies. In contrast, the A7R III 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, the A7R III 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 Pentax K-70 and the Sony A7R III 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.
The K-70 writes its imaging data to SDXC cards, while the A7R III uses SDXC or Memory Stick PRO Duo cards. The A7R III features dual card slots, which can be very useful in case a memory card fails. In contrast, the K-70 only has one slot. The A7R III supports UHS-II cards (on its first slot), while the K-70 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 K-70 and Sony Alpha A7R III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Olympus E-M1 II||Y||stereo||mono||Y||Y||micro||3.0||Y||-||-|
|Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
|Sony A99 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||Y|
|Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|Sony A7S II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A7R III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The K-70 lacks such a headphone port.
Studio photographers will appreciate that the Sony A7R III (unlike the K-70) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
The K-70 is a recent model that features in the current product line-up of Pentax. In contrast, the A7R III has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the A7R III was succeeded by the Sony A7R IV. 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 there a clear favorite between the Pentax K-70 and the Sony A7R III? Which camera is better? The listing below highlights the relative strengths of the two models.
Advantages of the Pentax K-70:
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- 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.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- More affordable: Was introduced into a lower priced category (80 percent cheaper at launch).
- More heavily discounted: Has been on the market for longer (launched in June 2016).
Reasons to prefer the Sony Alpha A7R III:
- More detail: Has more megapixels (42.2 vs 24MP), which boosts linear resolution by 33%.
- 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 1080/60i).
- 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 (0.78x vs 0.63x).
- More detailed LCD: Has a higher resolution rear screen (1440k vs 921k dots).
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/6000s) to freeze action.
- Faster burst: Shoots at higher frequency (10 vs 6 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- Longer lasting: Gets more shots (650 versus 410) 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 (3.1 vs 2.0).
- Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
- Easier wireless transfer: Supports Bluetooth for image sharing without cables.
- 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.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- More modern: Was introduced somewhat (1 year and 4 months) more recently.
If the count of individual advantages (bullet points above) is taken as a guide, the A7R III is the clear winner of the contest (24 : 6 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 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-70 and the Sony A7R 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 comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains incomplete and does no justice, for example, to the way the K-70 or the A7R 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 adjacent summary-table relays the overall verdicts of several of the most popular camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, and photographyblog). 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.
|Pentax K-70||..||79/100||4.5/5||4/5||4.5/5||Jun 2016||649|
|Sony A7R III||+ +||90/100||4.5/5||5/5||5/5||Oct 2017||3,199|
|Nikon Z7||+||89/100||4.5/5||4.5/5||5/5||Aug 2018||3,399|
|Olympus E-M1 II||+ +||85/100||4.5/5||5/5||4.5/5||Sep 2016||1,999|
|Panasonic G9||+ +||85/100||5/5||5/5||5/5||Nov 2017||1,699|
|Panasonic GH5||+ +||85/100||4.5/5||5/5||5/5||Jan 2017||1,999|
|Pentax KP||..||82/100||5/5||..||4.5/5||Jan 2017||1,099|
|Pentax K-3 II||..||..||5/5||4.5/5||5/5||Apr 2015||1,099|
|Pentax K-3||..||83/100||5/5||4.5/5||5/5||Oct 2013||1,299|
|Pentax K-5||..||83/100||5/5||4.5/5||4.5/5||Sep 2010||1,099|
|Sony A9||+ +||89/100||5/5||5/5||5/5||Apr 2017||4,499|
|Sony A99 II||..||85/100||4.5/5||4.5/5||4.5/5||Sep 2016||3,199|
|Sony A6500||+ +||85/100||4.5/5||5/5||4.5/5||Oct 2016||1,399|
|Sony A7R II||+ +||90/100||5/5||4.5/5||5/5||Jun 2015||3,199|
|Sony A7S II||+||..||4.5/5||5/5||5/5||Sep 2015||2,999|
|Sony A68||..||..||4/5||..||4/5||Nov 2015||699|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
Care should be taken when interpreting the review scores above, 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. It should also be noted that some of the review sites have over time altered the way they render their verdicts.
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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.
Specifications: Pentax K-70 vs Sony A7R 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 K-70||Sony A7R III|
|Camera Type||Digital single lens reflex||Mirrorless system camera|
|Camera Lens||Pentax K mount lenses||Sony E mount lenses|
|Launch Date||June 2016||October 2017|
|Launch Price||USD 649||USD 3,199|
|Sensor Specs||Pentax K-70||Sony A7R III|
|Sensor Format||APS-C Sensor||Full Frame Sensor|
|Sensor Size||23.5 x 15.6 mm||35.9 x 24.0 mm|
|Sensor Area||366.6 mm2||861.6 mm2|
|Sensor Diagonal||28.2 mm||43.2 mm|
|Sensor Resolution||24 Megapixels||42.2 Megapixels|
|Image Resolution||6000 x 4000 pixels||7952 x 5304 pixels|
|Pixel Pitch||3.91 μm||4.52 μm|
|Pixel Density||6.55 MP/cm2||4.90 MP/cm2|
|Moiré control||no AA filter||no AA filter|
|Movie Capability||1080/60i Video||4K/30p Video|
|ISO Setting||100 - 102,400 ISO||100 - 32,000 ISO|
|ISO Boost||no Enhancement||50 - 102,400 ISO|
|Image Processor||PRIME MII||BIONZ X|
|DXO Sensor Quality (score)||..||100|
|DXO Color Depth (bits)||..||26.0|
|DXO Dynamic Range (EV)||..||14.7|
|DXO Low Light (ISO)||..||3523|
|Screen Specs||Pentax K-70||Sony A7R III|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||3686k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||921k dots||1440k dots|
|LCD Attachment||Swivel screen||Tilting screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Pentax K-70||Sony A7R III|
|Focus System||Phase-detect AF||On-Sensor Phase-detect|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/6000s||1/8000s|
|Continuous Shooting||6 shutter flaps/s||10 shutter flaps/s|
|Shutter Life Expectancy||100 000 actuations||500 000 actuations|
|Electronic Shutter||no E-Shutter||YES|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||UHS-I||Single UHS-II|
|Connectivity Specs||Pentax K-70||Sony A7R III|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 2.0||USB 3.1|
|HDMI Port||mini HDMI||micro HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||no Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Bluetooth Support||no Bluetooth||Bluetooth built-in|
|Body Specs||Pentax K-70||Sony A7R III|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||410 shots per charge||650 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
126 x 93 x 74 mm
(5.0 x 3.7 x 2.9 in)
127 x 96 x 74 mm
(5.0 x 3.8 x 2.9 in)
|Camera Weight||688 g (24.3 oz)||650 g (22.9 oz)|
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