Pentax K-5 vs Sony A77
The Pentax K-5 and the Sony Alpha SLT-A77 are two enthusiast cameras that were revealed to the public, respectively, in September 2010 and August 2011. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Pentax has a resolution of 16.1 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.
|Pentax K-5||Sony A77|
|Digital single lens reflex||Digital single lens reflex|
|Pentax K mount lenses||Sony A mount lenses|
|16.1 MP, APS-C Sensor||24 MP, APS-C Sensor|
|1080/25p Video||1080/60p Video|
|ISO 100-12,800 (80 - 51,200)||ISO 100-16,000 (50 - 25,600)|
|Optical viewfinder||Electronic viewfinder (2359k dots)|
|3.0 LCD, 921k dots||3.0 LCD, 921k dots|
|Fixed screen (not touch-sensitive)||Fully flexible screen (no touchscreen)|
|7 shutter flaps per second||12 shutter flaps per second|
|In-body stabilization||In-body stabilization|
|Weathersealed body||Weathersealed body|
|740 shots per battery charge||470 shots per battery charge|
|131 x 97 x 73 mm, 760 g||143 x 104 x 81 mm, 732 g|
Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-5 and the Sony Alpha SLT-A77? 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-5 and the Sony A77 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.
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A77 is notably larger (17 percent) than the Pentax K-5. However, the A77 is slightly lighter (4 percent) than the K-5. 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 table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. If you want to switch the focus of the display and review another camera pair, just select a new right or left comparator from among the camera models in the table. Alternatively, you can also move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.
|Pentax K-5||131 mm||97 mm||73 mm||760 g||740||Y||Sep 2010||1,099|
|Sony A77||143 mm||104 mm||81 mm||732 g||470||Y||Aug 2011||1,399|
|Nikon D7000||132 mm||105 mm||77 mm||780 g||1050||Y||Sep 2010||1,499|
|Olympus E-M5 II||124 mm||85 mm||45 mm||469 g||310||Y||Feb 2015||1,099|
|Olympus E-M5||122 mm||89 mm||43 mm||425 g||360||Y||Feb 2012||1,299|
|Panasonic GH5||139 mm||98 mm||87 mm||725 g||410||Y||Jan 2017||1,999|
|Pentax KP||132 mm||101 mm||76 mm||703 g||390||Y||Jan 2017||1,099|
|Pentax K-70||126 mm||93 mm||74 mm||688 g||410||Y||Jun 2016||649|
|Pentax K-3 II||131 mm||100 mm||77 mm||800 g||720||Y||Apr 2015||1,099|
|Pentax K-3||131 mm||100 mm||77 mm||800 g||560||Y||Oct 2013||1,299|
|Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
|Sony A77 II||143 mm||104 mm||81 mm||647 g||480||Y||May 2014||1,199|
|Sony A99||147 mm||111 mm||78 mm||812 g||500||Y||Sep 2012||2,799|
|Sony A850||156 mm||117 mm||82 mm||895 g||880||Y||Aug 2009||1,999|
Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
(1) Number of images that can be taken on a full battery charge according to the CIPA-standard; (2) Official announcement.
Any camera decision will obviously take relative prices into account. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The K-5 was launched at a somewhat lower price (by 21 percent) than the A77, which makes it more attractive for photographers on a tight budget. 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. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixels in a sensor of the same technological generation. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the background. On the downside, larger sensors tend to be associated with larger, more expensive camera bodies and lenses.
Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the A77 is 1 percent smaller. They nevertheless have the same format factor of 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.
Despite having a slightly smaller sensor, the A77 offers a higher resolution of 24 megapixels, compared with 16.1 MP of the K-5. 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 3.91μm versus 4.81μm for the K-5). However, it should be noted that the A77 is a somewhat more recent model (by 11 months) than the K-5, and its sensor might have benefitted from technological advances during this time that partly offset its pixel-size disadvantage.
The resolution advantage of the Sony A77 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A77 for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the Pentax K-5 are 24.6 x 16.3 inches or 62.6 x 41.5 cm for good quality, 19.7 x 13.1 inches or 50.1 x 33.2 cm for very good quality, and 16.4 x 10.9 inches or 41.7 x 27.6 cm for excellent quality prints.
The Pentax K-5 has a native sensitivity range from ISO 100 to ISO 12800, which can be extended to ISO 80-51200. The corresponding ISO settings for the Sony Alpha SLT-A77 are ISO 100 to ISO 16000, with the possibility to increase the ISO range to 50-25600.
Consistent information on actual sensor performance is available from DXO Mark for many cameras. This service assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. Of the two cameras under review, the K-5 has a notably higher overall DXO score than the A77 (overall score 4 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.3 bits lower color depth, 0.9 EV in additional dynamic range, and 0.5 stops in additional low light sensitivity. The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.
|Olympus E-M5 II||Four Thirds||15.9||4608||3456||1080/60p||23.0||12.5||842||73|
|Olympus E-M5||Four Thirds||15.9||4608||3456||1080/60i||22.8||12.3||826||71|
|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 A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|Sony A77 II||APS-C||24.0||6000||4000||1080/60p||..||..||..||..|
|Sony A99||Full Frame||24.0||6000||4000||1080/60p||25.0||14.0||1555||89|
|Sony A850||Full Frame||24.4||6048||4032||none||23.8||12.2||1415||79|
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 A77 provides a faster frame rate than the K-5. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/25p.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the A77 has an electronic viewfinder (2359k dots), while the K-5 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 has a higher magnification than the one of the K-5 (0.73x vs 0.61x), 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 K-5, the Sony A77, and comparable cameras.
|Olympus E-M5 II||2360||n||3.0||1037||swivel||Y||1/8000s||10.0||n||Y|
|Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y|
|Sony A7 II||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y|
|Sony A77 II||2359||Y||3.0||1229||full-flex||n||1/8000s||12.0||Y||Y|
The Pentax K-5 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-5 writes its imaging data to SDXC cards, while the A77 uses SDXC or Memory Stick PRO Duo cards. The A77 supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the K-5 cannot take advantage of Ultra High Speed SD 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-5 and Sony Alpha SLT-A77 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
|Olympus E-M5 II||Y||stereo||mono||Y||-||micro||2.0||Y||-||-|
|Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
|Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|Sony A77 II||Y||stereo||mono||Y||-||mini||2.0||Y||Y||-|
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 A77 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.
Both the K-5 and the A77 have been discontinued, but can regularly be found used on eBay. The K-5 was replaced by the Pentax K-5 II, while the A77 was followed by the Sony A77 II. 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-5 or the Sony A77 – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.
Reasons to prefer the Pentax K-5:
- Better image quality: Scores markedly higher (4 points) in the DXO overall assessment.
- More dynamic range: Captures a larger spectrum of light and dark details (0.9 EV of extra DR).
- Better low-light sensitivity: Requires less light for good images (0.5 stops ISO advantage).
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More compact: Is smaller (131x97mm vs 143x104mm) and thus needs less room in the bag.
- Longer lasting: Can take more shots (740 versus 470) on a single battery charge.
- More affordable: Was introduced into a lower priced segment (21 percent cheaper at launch).
- More heavily discounted: Has been on the market for longer (launched in September 2010).
Arguments in favor of the Sony Alpha SLT-A77:
- More detail: Has more megapixels (24 vs 16.1MP), which boosts linear resolution by 22%.
- Better video: Provides higher movie framerates (1080/60p versus 1080/25p).
- More framing info: Has an electronic viewfinder that displays shooting data.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.73x vs 0.61x).
- 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 7 flaps/sec) to capture the decisive moment.
- Easier geotagging: Features an internal GPS sensor to log localization data.
- Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
- More modern: Was introduced somewhat (11 months) more recently.
If the number of relative strengths (bullet points above) is taken as a guide, the A77 comes out slightly ahead of the K-5 (10 : 9 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. 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-5 and the Sony A77 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 says little about, for example, the shooting experience and imaging performance of the K-5 and the A77 in practical situations. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.
This is why expert reviews are important. The following table reports the overall ratings of the cameras as published by some of the major camera review sites (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-5||..||83/100||5/5||4.5/5||4.5/5||Sep 2010||1,099|
|Sony A77||91/100||81/100||..||4.5/5||5/5||Aug 2011||1,399|
|Nikon D7000||..||80/100||4.5/5||5/5||4.5/5||Sep 2010||1,499|
|Olympus E-M5 II||+ +||81/100||5/5||4.5/5||5/5||Feb 2015||1,099|
|Olympus E-M5||+ +||80/100||4.5/5||5/5||5/5||Feb 2012||1,299|
|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-70||..||79/100||4.5/5||4/5||4.5/5||Jun 2016||649|
|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|
|Sony A9||+ +||89/100||5/5||5/5||5/5||Apr 2017||4,499|
|Sony A7 II||+||82/100||4.5/5||5/5||5/5||Nov 2014||1,999|
|Sony A77 II||..||80/100||4.5/5||4/5||5/5||May 2014||1,199|
|Sony A99||..||84/100||4.5/5||o||4.5/5||Sep 2012||2,799|
|Sony A850||..||75/100||..||4/5||4.5/5||Aug 2009||1,999|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The review scores listed above should be treated with care, 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 comparisons of ratings among very different cameras or across long time periods have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.
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.
- Canon 30D vs Pentax K-5
- Canon G5 X vs Sony A77 II
- Canon T5i vs Sony A77
- Hasselblad X1D vs Sony A77
- Leica Q Typ 116 vs Pentax K-5
- Nikon D50 vs Sony A77 II
- Olympus E-30 vs Sony A77 II
- Olympus E-420 vs Sony A77 II
- Olympus E-520 vs Sony A77
- Olympus XZ-1 vs Sony A77
- Panasonic G10 vs Sony A77
- Panasonic G10 vs Sony A77 II
Specifications: Pentax K-5 vs Sony A77
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-5||Sony A77|
|Camera Type||Digital single lens reflex||Digital single lens reflex|
|Camera Lens||Pentax K mount lenses||Sony A mount lenses|
|Launch Date||September 2010||August 2011|
|Launch Price||USD 1,099||USD 1,399|
|Sensor Specs||Pentax K-5||Sony A77|
|Sensor Format||APS-C Sensor||APS-C Sensor|
|Sensor Size||23.7 x 15.7 mm||23.5 x 15.6 mm|
|Sensor Area||372.09 mm2||366.6 mm2|
|Sensor Diagonal||28.4 mm||28.2 mm|
|Sensor Resolution||16.1 Megapixels||24 Megapixels|
|Image Resolution||4928 x 3264 pixels||6000 x 4000 pixels|
|Pixel Pitch||4.81 μm||3.91 μm|
|Pixel Density||4.32 MP/cm2||6.55 MP/cm2|
|Moiré control||Anti-Alias filter||Anti-Alias filter|
|Movie Capability||1080/25p Video||1080/60p Video|
|ISO Setting||100 - 12,800 ISO||100 - 16,000 ISO|
|ISO Boost||80 - 51,200 ISO||50 - 25,600 ISO|
|Image Processor||PRIME II||BIONZ X|
|DXO Sensor Quality (score)||82||78|
|DXO Color Depth (bits)||23.7||24.0|
|DXO Dynamic Range (EV)||14.1||13.2|
|DXO Low Light (ISO)||1162||801|
|Screen Specs||Pentax K-5||Sony A77|
|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||3.0inch||3.0inch|
|LCD Resolution||921k dots||921k dots|
|LCD Attachment||Fixed screen||Fully flexible screen|
|Shooting Specs||Pentax K-5||Sony A77|
|Focus System||Phase-detect AF||Phase-detect AF|
|Manual Focusing Aid||no Peaking Feature||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/8000s|
|Continuous Shooting||7 shutter flaps/s||12 shutter flaps/s|
|Shutter Life Expectancy||100 000 actuations||150 000 actuations|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||Build-in Flash||Build-in Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Single card slot||Single card slot|
|UHS card support||no||UHS-I|
|Connectivity Specs||Pentax K-5||Sony A77|
|Studio Flash||PC Sync socket||PC Sync socket|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||mini HDMI||mini HDMI|
|Microphone Port||External MIC port||External MIC port|
|Wifi Support||no Wifi||no Wifi|
|Geotagging||no internal GPS||GPS built-in|
|Body Specs||Pentax K-5||Sony A77|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||740 shots per charge||470 shots per charge|
131 x 97 x 73 mm
(5.2 x 3.8 x 2.9 in)
143 x 104 x 81 mm
(5.6 x 4.1 x 3.2 in)
|Camera Weight||760 g (26.8 oz)||732 g (25.8 oz)|
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