Pentax K-3 II vs Sony A77 II
The Pentax K-3 II and the Sony Alpha SLT-A77 II are two enthusiast cameras that were announced, respectively, in April 2015 and May 2014. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Pentax has a resolution of 24.1 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.
Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-3 II and the Sony Alpha SLT-A77 II? 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 side-by-side display below illustrates the physical size and weight of the Pentax K-3 II and the Sony A77 II. 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 A77 II 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 A77 II is notably larger (14 percent) than the Pentax K-3 II. However, the A77 II is markedly lighter (19 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.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.
|1.||Pentax K-3 II||131 mm||100 mm||77 mm||800 g||720||Y||Apr 2015||1,099|
|2.||Sony A77 II||143 mm||104 mm||81 mm||647 g||480||Y||May 2014||1,199|
|3.||Canon 80D||139 mm||105 mm||79 mm||730 g||960||Y||Feb 2016||1,199|
|4.||Nikon D7200||136 mm||107 mm||76 mm||765 g||1110||Y||Mar 2015||1,199|
|5.||Nikon D7100||136 mm||107 mm||76 mm||765 g||950||Y||Feb 2013||1,199|
|6.||Pentax K-3 III||135 mm||104 mm||74 mm||820 g||800||Y||Mar 2021||1,999|
|7.||Pentax KP||132 mm||101 mm||76 mm||703 g||390||Y||Jan 2017||1,099|
|8.||Pentax K-70||126 mm||93 mm||74 mm||688 g||410||Y||Jun 2016||649|
|9.||Pentax K-S2||123 mm||91 mm||73 mm||678 g||410||Y||Feb 2015||749|
|10.||Pentax K-S1||121 mm||93 mm||70 mm||558 g||410||n||Aug 2014||749|
|11.||Pentax K-3||131 mm||100 mm||77 mm||800 g||560||Y||Oct 2013||1,299|
|12.||Pentax K-5 II||131 mm||97 mm||73 mm||760 g||740||Y||Sep 2012||1,099|
|13.||Pentax K-5||131 mm||97 mm||73 mm||760 g||740||Y||Sep 2010||1,099|
|14.||Sony A68||143 mm||104 mm||81 mm||610 g||540||n||Nov 2015||699|
|15.||Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
|16.||Sony A77||143 mm||104 mm||81 mm||732 g||470||Y||Aug 2011||1,399|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
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 K-3 II was somewhat cheaper (by 8 percent) than the A77 II 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.
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 tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units 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 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.
While the two cameras under review share the same sensor size, the K-3 II offers a slightly higher resolution of 24.1 megapixels, compared with 24 MP of the A77 II. This megapixels advantage translates into a 0.3 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 3.91μm for the A77 II). In this context, it should be noted, however, that the K-3 II is a somewhat more recent model (by 11 months) than the A77 II, 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-3 II has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
Unlike the A77 II, 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 corresponding ISO settings for the Sony Alpha SLT-A77 II are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-51200.
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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
|1.||Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
|2.||Sony A77 II||APS-C||24.0||6000||4000||1080/60p||..||..||..||..|
|6.||Pentax K-3 III||APS-C||25.6||6192||4128||4K/30p||..||..||..||..|
|12.||Pentax K-5 II||APS-C||16.1||4928||3264||1080/25p||23.8||14.1||1235||82|
|15.||Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A77 II provides a faster frame rate than the K-3 II. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.
Apart from body and sensor, cameras can and do differ across a range of features. For example, the A77 II has an electronic viewfinder (2359k dots), while the K-3 II 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 A77 II has a higher magnification than the one of the K-3 II (0.73x vs 0.63x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Pentax K-3 II and Sony A77 II along with similar information for a selection of comparators.
|1.||Pentax K-3 II||optical||Y||3.2 / 1037||fixed||n||1/8000s||8.3||n||Y|
|2.||Sony A77 II||2359||Y||3.0 / 1229||full-flex||n||1/8000s||12.0||Y||Y|
|3.||Canon 80D||optical||Y||3.0 / 1040||swivel||Y||1/8000s||7.0||Y||n|
|4.||Nikon D7200||optical||Y||3.2 / 1229||fixed||n||1/8000s||6.0||Y||n|
|5.||Nikon D7100||optical||Y||3.2 / 1229||fixed||n||1/8000s||6.0||Y||n|
|6.||Pentax K-3 III||optical||Y||3.2 / 1620||fixed||Y||1/8000s||12.0||n||Y|
|7.||Pentax KP||optical||n||3.0 / 921||tilting||n||1/6000s||7.0||Y||Y|
|8.||Pentax K-70||optical||n||3.0 / 921||swivel||n||1/6000s||6.0||Y||Y|
|9.||Pentax K-S2||optical||n||3.0 / 921||swivel||n||1/6000s||5.4||Y||Y|
|10.||Pentax K-S1||optical||n||3.0 / 921||fixed||n||1/6000s||5.4||Y||Y|
|11.||Pentax K-3||optical||Y||3.2 / 1037||fixed||n||1/8000s||8.3||Y||Y|
|12.||Pentax K-5 II||optical||Y||3.0 / 921||fixed||n||1/8000s||7.0||Y||Y|
|13.||Pentax K-5||optical||Y||3.0 / 921||fixed||n||1/8000s||7.0||Y||Y|
|14.||Sony A68||1440||Y||2.7 / 460||tilting||n||1/4000s||8.0||Y||Y|
|15.||Sony A7 II||2400||n||3.0 / 1230||tilting||n||1/8000s||5.0||n||Y|
|16.||Sony A77||2359||Y||3.0 / 921||full-flex||n||1/8000s||12.0||Y||Y|
One difference between the cameras concerns the presence of an on-board flash. The A77 II has one, while the K-3 II does not. While the built-in flash of the A77 II is not very powerful, it can at times be useful as a fill-in light.The A77 II 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 K-3 II does not have a selfie-screen.
The Pentax K-3 II 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-3 II writes its imaging data to SDXC cards, while the A77 II uses SDXC or Memory Stick PRO Duo cards. The K-3 II features dual card slots, which can be very useful in case a memory card fails. In contrast, the A77 II 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.
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 Sony Alpha SLT-A77 II and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
Mic / Speaker
|1.||Pentax K-3 II||Y||mono / mono||Y||Y||mini||3.0||-||-||-|
|2.||Sony A77 II||Y||stereo / mono||Y||-||mini||2.0||Y||Y||-|
|3.||Canon 80D||Y||stereo / mono||Y||Y||mini||2.0||Y||Y||-|
|4.||Nikon D7200||Y||stereo / mono||Y||Y||mini||2.0||Y||Y||-|
|5.||Nikon D7100||Y||stereo / mono||Y||Y||mini||2.0||-||-||-|
|6.||Pentax K-3 III||Y||stereo / mono||Y||Y||micro||3.2||Y||-||Y|
|7.||Pentax KP||Y||stereo / mono||Y||-||-||2.0||Y||-||-|
|8.||Pentax K-70||Y||stereo / mono||Y||-||mini||2.0||Y||-||-|
|9.||Pentax K-S2||Y||mono / mono||Y||-||micro||2.0||Y||Y||-|
|10.||Pentax K-S1||Y||stereo / mono||-||-||micro||2.0||-||-||-|
|11.||Pentax K-3||Y||mono / mono||Y||Y||mini||3.0||-||-||-|
|12.||Pentax K-5 II||Y||stereo / mono||Y||-||mini||2.0||-||-||-|
|13.||Pentax K-5||Y||stereo / mono||Y||-||mini||2.0||-||-||-|
|14.||Sony A68||Y||stereo / mono||Y||-||micro||2.0||-||-||-|
|15.||Sony A7 II||Y||stereo / mono||Y||Y||micro||2.0||Y||Y||-|
|16.||Sony A77||Y||stereo / mono||Y||-||mini||2.0||-||-||-|
It is notable that the K-3 II has a headphone jack, which is not present on the A77 II This port makes it possible to attach external headphones and monitor the quality of sound during the recording process.
Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.
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.
The A77 II is a recent model that features in the current product line-up of Sony. In contrast, the K-3 II has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the K-3 II was succeeded by the Pentax K-3 III. 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? Which of the two cameras – the Pentax K-3 II or the Sony A77 II – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.
Advantages of the Pentax K-3 II:
- 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.
- Better sound control: Has a headphone port that enables audio monitoring while recording.
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More compact: Is smaller (131x100mm vs 143x104mm) and thus needs less room in the bag.
- Longer lasting: Can take more shots (720 versus 480) 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).
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- More modern: Is somewhat more recent (announced 11 months after the A77 II).
Arguments in favor of the Sony Alpha SLT-A77 II:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
- More framing info: Has an electronic viewfinder that displays shooting data.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.73x vs 0.63x).
- More detailed LCD: Has a higher resolution rear screen (1229k vs 1037k dots).
- More flexible LCD: Has a full-flex 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 burst: Shoots at higher frequency (12 vs 8.3 flaps/sec) to capture the decisive moment.
- Less heavy: Has a lower weight (by 153g or 19 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 heavily discounted: Has been on the market for longer (launched in May 2014).
If the count of relative strengths (bullet points above) is taken as a measure, the A77 II comes out slightly ahead of the K-3 II (13 : 12 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-3 II and the Sony A77 II 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 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 K-3 II or the A77 II perform in practice. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.
This is why expert reviews 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.
|1.||Pentax K-3 II||4.5/5||..||..||..||5/5||5/5||Apr 2015||1,099|
|2.||Sony A77 II||4/5||..||..||80/100||4.5/5||5/5||May 2014||1,199|
|3.||Canon 80D||4/5||+ +||4.5/5||84/100||4.5/5||4.5/5||Feb 2016||1,199|
|4.||Nikon D7200||4/5||+ +||..||84/100||4.5/5||4.5/5||Mar 2015||1,199|
|5.||Nikon D7100||5/5||+ +||..||85/100||4.5/5||4.5/5||Feb 2013||1,199|
|6.||Pentax K-3 III||4/5||..||3/5||..||4.5/5||..||Mar 2021||1,999|
|7.||Pentax KP||4/5||..||3/5||82/100||5/5||4.5/5||Jan 2017||1,099|
|8.||Pentax K-70||4.5/5||..||..||79/100||4.5/5||4.5/5||Jun 2016||649|
|9.||Pentax K-S2||4.5/5||..||..||..||5/5||4.5/5||Feb 2015||749|
|10.||Pentax K-S1||4/5||..||..||..||4.5/5||4/5||Aug 2014||749|
|11.||Pentax K-3||4/5||..||..||83/100||5/5||5/5||Oct 2013||1,299|
|12.||Pentax K-5 II||5/5||..||..||80/100||5/5||4.5/5||Sep 2012||1,099|
|13.||Pentax K-5||4/5||..||..||83/100||5/5||4.5/5||Sep 2010||1,099|
|14.||Sony A68||3/5||..||..||..||4/5||4/5||Nov 2015||699|
|15.||Sony A7 II||5/5||+||4/5||82/100||4.5/5||5/5||Nov 2014||1,999|
|16.||Sony A77||5/5||91/100||..||81/100||..||5/5||Aug 2011||1,399|
|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, please note that some of the review sites have changed their methodology and reporting over time.
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 make a corresponding selection in the search boxes below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.
- Canon M6 Mark II vs Pentax K-3 II
- Canon M6 vs Pentax K-3 II
- Canon SX720 vs Sony A77 II
- Canon T5 vs Sony A77 II
- Fujifilm X100 vs Pentax K-3 II
- Fujifilm X100F vs Sony A77 II
- Fujifilm X70 vs Sony A77 II
- Nikon D5100 vs Sony A77 II
- Nikon W150 vs Pentax K-3 II
- Olympus E-30 vs Sony A77 II
- Pentax K-3 II vs Sony A7 II
Specifications: Pentax K-3 II vs Sony A77 II
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-3 II||Sony A77 II|
|Camera Type||Digital single lens reflex||Digital single lens reflex|
|Camera Lens||Pentax K mount lenses||Sony A mount lenses|
|Launch Date||April 2015||May 2014|
|Launch Price||USD 1,099||USD 1,199|
|Sensor Specs||Pentax K-3 II||Sony A77 II|
|Sensor Format||APS-C Sensor||APS-C Sensor|
|Sensor Size||23.5 x 15.6 mm||23.5 x 15.6 mm|
|Sensor Area||366.6 mm2||366.6 mm2|
|Sensor Diagonal||28.2 mm||28.2 mm|
|Sensor Resolution||24.1 Megapixels||24 Megapixels|
|Image Resolution||6016 x 4000 pixels||6000 x 4000 pixels|
|Pixel Pitch||3.90 μm||3.91 μm|
|Pixel Density||6.56 MP/cm2||6.55 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||1080/60i Video||1080/60p Video|
|ISO Setting||100 - 51,200 ISO||100 - 25,600 ISO|
|ISO Boost||no Enhancement||50 - 51,200 ISO|
|Image Processor||PRIME III||BIONZ X|
|DXO Sensor Quality (score)||80||..|
|DXO Color Depth (bits)||23.6||..|
|DXO Dynamic Range (EV)||13.6||..|
|DXO Low Light (ISO)||1106||..|
|Screen Specs||Pentax K-3 II||Sony A77 II|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2359k dots|
|Top-Level Screen||Control Panel||Control Panel|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.2inch||3.0inch|
|LCD Resolution||1037k dots||1229k dots|
|LCD Attachment||Fixed screen||Fully flexible screen|
|Shooting Specs||Pentax K-3 II||Sony A77 II|
|Focus System||Phase-detect AF||Phase-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/8000s|
|Continuous Shooting||8.3 shutter flaps/s||12 shutter flaps/s|
|Shutter Life Expectancy||200 000 actuations||150 000 actuations|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||no On-Board Flash||Built-in Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Dual card slots||Single card slot|
|UHS card support||UHS-I||UHS-I|
|Connectivity Specs||Pentax K-3 II||Sony A77 II|
|Studio Flash||PC Sync socket||PC Sync socket|
|USB Connector||USB 3.0||USB 2.0|
|HDMI Port||mini HDMI||mini HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||Headphone port||no Headphone port|
|Wifi Support||no Wifi||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Geotagging||GPS built-in||no internal GPS|
|Body Specs||Pentax K-3 II||Sony A77 II|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||720 shots per charge||480 shots per charge|
131 x 100 x 77 mm
(5.2 x 3.9 x 3.0 in)
143 x 104 x 81 mm
(5.6 x 4.1 x 3.2 in)
|Camera Weight||800 g (28.2 oz)||647 g (22.8 oz)|
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