Pentax K-3 vs Sony A77
The Pentax K-3 and the Sony Alpha SLT-A77 are two enthusiast cameras that were revealed to the public, respectively, in October 2013 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 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.
|Pentax K-3||Sony A77|
|Digital single lens reflex||Digital single lens reflex|
|Pentax K mount lenses||Sony A mount lenses|
|24.1 MP, APS-C Sensor||24 MP, APS-C Sensor|
|1080/60i Video||1080/60p Video|
|ISO 100-51200||ISO 100-16000 (50-25600)|
|Optical viewfinder||Electronic viewfinder (2359k dots)|
|3.2" LCD, 1037k dots||3.0" LCD, 921k dots|
|Fixed screen (not touch-sensitive)||Fully flexible screen (no touchscreen)|
|8.3 shutter flaps per second||12 shutter flaps per second|
|In-body stabilization||In-body stabilization|
|Weathersealed body||Weathersealed body|
|560 shots per battery charge||470 shots per battery charge|
|131 x 100 x 77 mm, 800 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-3 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.
Body comparison: Pentax K-3 vs Sony A77
The physical size and weight of the Pentax K-3 and the Sony A77 are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth measures are rounded to the nearest millimeter.
The K-3 can be obtained in two different colors (black, silver), while the A77 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 is notably larger (14 percent) than the Pentax K-3. However, the A77 is markedly lighter (9 percent) than the K-3. 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 would like to visualize and compare a different camera combination, just use the right or left arrows in the table to switch to the respective camera. Alternatively, you can also navigate to the CAM-parator app and make your selection from the full list of cameras there.
|Pentax K-3»||5.2 in||3.9 in||3.0 in||28.2 oz||560||Y||Oct 2013||1,299||-||Pentax K-3|
|Sony A77«||5.6 in||4.1 in||3.2 in||25.8 oz||470||Y||Aug 2011||1,399||-||Sony A77|
|Canon 70D« »||5.5 in||4.1 in||3.1 in||26.6 oz||920||Y||Jul 2013||1,199||-||Canon 70D|
|Nikon D7200« »||5.4 in||4.2 in||3.0 in||27.0 oz||1110||Y||Mar 2015||1,199||-||Nikon D7200|
|Nikon D7100« »||5.4 in||4.2 in||3.0 in||27.0 oz||950||Y||Feb 2013||1,199||-||Nikon D7100|
|Pentax KP« »||5.2 in||4.0 in||3.0 in||24.8 oz||390||Y||Jan 2017||1,099||Pentax KP|
|Pentax K-70« »||5.0 in||3.7 in||2.9 in||24.3 oz||410||Y||Jun 2016||649||Pentax K-70|
|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 II|
|Pentax K-5« »||5.2 in||3.8 in||2.9 in||26.8 oz||740||Y||Sep 2010||1,099||-||Pentax K-5|
|Sony A6500« »||4.7 in||2.6 in||2.1 in||16.0 oz||350||Y||Oct 2016||1,399||Sony A6500|
|Sony A7 II« »||5.0 in||3.8 in||2.4 in||21.1 oz||350||Y||Nov 2014||1,999||-||Sony A7 II|
|Sony A77 II« »||5.6 in||4.1 in||3.2 in||22.8 oz||480||Y||May 2014||1,199||Sony A77 II|
|Sony A99« »||5.8 in||4.4 in||3.1 in||28.6 oz||500||Y||Sep 2012||2,799||-||Sony A99|
|Note: Measurements and pricing do not include easily detachable parts, such as 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 K-3 was somewhat cheaper (by 7 percent) than the A77 at launch, but both cameras fall into the same price category. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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.
Sensor comparison: Pentax K-3 vs Sony A77
The size of the imaging sensor is a crucial determinant 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. 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 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 offers a slightly higher resolution of 24.1 megapixels, compared with 24 MP of the A77. 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 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). In this context, it should be noted, however, that the K-3 is much more recent (by 2 years and 1 month) than the A77, and its sensor will have benefitted from technological advances during this time that compensate for the smaller pixel size. Coming back to sensor resolution, it should be mentioned that the K-3 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The Pentax K-3 has a native sensitivity range from ISO 100 to ISO 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.
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 Overall DXO ratings for the two cameras under consideration are close, suggesting that they provide similar imaging performance. The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.
|Pentax K-3»||APS-C||24.1||6016||4000||1080/60i||23.7||13.4||1216||80||Pentax K-3|
|Sony A77«||APS-C||24.0||6000||4000||1080/60p||24.0||13.2||801||78||Sony A77|
|Canon 70D« »||APS-C||20.0||5472||3648||1080/30p||22.5||11.6||926||68||Canon 70D|
|Nikon D7200« »||APS-C||24.0||6000||4000||1080/60p||24.5||14.6||1333||87||Nikon D7200|
|Nikon D7100« »||APS-C||24.0||6000||4000||1080/60p||24.2||13.7||1256||83||Nikon D7100|
|Pentax KP« »||APS-C||24.1||6016||4000||1080/60i||-||-||-||-||Pentax KP|
|Pentax K-70« »||APS-C||24.0||6000||4000||1080/60i||-||-||-||-||Pentax K-70|
|Pentax K-3 II« »||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80||Pentax K-3 II|
|Pentax K-5« »||APS-C||16.1||4928||3264||1080/25p||23.7||14.1||1162||82||Pentax K-5|
|Sony A6500« »||APS-C||24.0||6000||4000||4K/30p||24.5||13.7||1405||85||Sony A6500|
|Sony A7 II« »||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90||Sony A7 II|
|Sony A77 II« »||APS-C||24.0||6000||4000||1080/60p||-||-||-||-||Sony A77 II|
|Sony A99« »||Full Frame||24.0||6000||4000||1080/60p||25.0||14.0||1555||89||Sony A99|
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-3. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.
Feature comparison: Pentax K-3 vs Sony A77
Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A77 has an electronic viewfinder (2359k dots), while the K-3 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-3 (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 following table reports on some other key feature differences and similarities of the Pentax K-3, the Sony A77, and comparable cameras.
|Pentax K-3»||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||Y||Y||Pentax K-3|
|Sony A77«||2359||Y||3.0||921||full-flex||n||1/8000s||12.0||Y||Y||Sony A77|
|Canon 70D« »||optical||Y||3.0||1040||swivel||Y||1/8000s||7.0||Y||n||Canon 70D|
|Nikon D7200« »||optical||Y||3.2||1229||fixed||n||1/8000s||6.0||Y||n||Nikon D7200|
|Nikon D7100« »||optical||Y||3.2||1229||fixed||n||1/8000s||6.0||Y||n||Nikon D7100|
|Pentax KP« »||optical||n||3.0||921||tilting||n||1/6000s||7.0||Y||Y||Pentax KP|
|Pentax K-70« »||optical||n||3.0||921||swivel||n||1/6000s||6.0||Y||Y||Pentax K-70|
|Pentax K-3 II« »||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y||Pentax K-3 II|
|Pentax K-5« »||optical||Y||3.0||921||fixed||n||1/8000s||7.0||Y||Y||Pentax K-5|
|Sony A6500« »||2359||n||3.0||922||tilting||Y||1/4000s||11.0||Y||Y||Sony A6500|
|Sony A7 II« »||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y||Sony A7 II|
|Sony A77 II« »||2359||Y||3.0||1229||full-flex||n||1/8000s||12.0||Y||Y||Sony A77 II|
|Sony A99« »||2359||Y||3.0||1229||full-flex||n||1/8000s||6.0||n||Y||Sony A99|
The Pentax K-3 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 writes its imaging data to SDXC cards, while the A77 uses SDXC or Memory Stick PRO Duo cards. The K-3 features dual card slots, which can be very useful in case a memory card fails. In contrast, the A77 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.
Connectivity comparison: Pentax K-3 vs Sony A77
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 and Sony Alpha SLT-A77 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
|Pentax K-3»||Y||mono||mono||Y||Y||mini||3.0||-||-||-||Pentax K-3|
|Sony A77«||Y||stereo||mono||Y||-||mini||2.0||-||-||-||Sony A77|
|Canon 70D« »||Y||stereo||mono||Y||-||mini||2.0||Y||-||-||Canon 70D|
|Nikon D7200« »||Y||stereo||mono||Y||Y||mini||2.0||Y||Y||-||Nikon D7200|
|Nikon D7100« »||Y||stereo||mono||Y||Y||mini||2.0||-||-||-||Nikon D7100|
|Pentax KP« »||Y||stereo||mono||Y||-||-||2.0||Y||-||-||Pentax KP|
|Pentax K-70« »||Y||stereo||mono||Y||-||mini||2.0||Y||-||-||Pentax K-70|
|Pentax K-3 II« »||Y||mono||mono||Y||Y||mini||3.0||-||-||-||Pentax K-3 II|
|Pentax K-5« »||Y||stereo||mono||Y||-||mini||2.0||-||-||-||Pentax K-5|
|Sony A6500« »||Y||stereo||mono||Y||-||micro||2.0||Y||Y||-||Sony A6500|
|Sony A7 II« »||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-||Sony A7 II|
|Sony A77 II« »||Y||stereo||mono||Y||-||mini||2.0||Y||Y||-||Sony A77 II|
|Sony A99« »||Y||stereo||mono||Y||Y||mini||2.0||-||-||-||Sony A99|
It is notable that the K-3 has a headphone jack, which is not present on the A77 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.
Both the K-3 and the A77 have been discontinued, but can regularly be found used on eBay. The A77 was replaced by the Sony A77 II, while the K-3 was followed by the Pentax K-3 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.
Review summary: Pentax K-3 vs Sony A77
So how do things add up? Which of the two cameras – the Pentax K-3 or the Sony A77 – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.
Reasons to prefer the Pentax K-3:
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- Better low-light sensitivity: Requires less light for good images (0.6 stops ISO advantage).
- 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.
- More detailed LCD: Has a higher resolution rear screen (1037k vs 921k dots).
- 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 (560 versus 470) on a single battery charge.
- 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: Reflects 2 years and 1 month of technical progress since the A77 launch.
Arguments in favor of the Sony Alpha SLT-A77:
- 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 flexible LCD: Has 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.
- More heavily discounted: Has been around for much longer (launched in August 2011).
If the count of relative strengths (bullet points above) is taken as a measure, the K-3 is the clear winner of the match-up (12 : 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 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-3 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 comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the K-3 and the A77 in practical situations. 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.
Expert reviews: Pentax K-3 vs Sony A77
This is why expert reviews 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-3»||-||83/100||5/5||4.5/5||5/5||Oct 2013||1,299||-||Pentax K-3|
|Sony A77«||91/100||81/100||-||4.5/5||5/5||Aug 2011||1,399||-||Sony A77|
|Canon 70D« »||+ +||83/100||4.5/5||4.5/5||5/5||Jul 2013||1,199||-||Canon 70D|
|Nikon D7200« »||+ +||84/100||4.5/5||4/5||4.5/5||Mar 2015||1,199||-||Nikon D7200|
|Nikon D7100« »||+ +||85/100||4.5/5||5/5||4.5/5||Feb 2013||1,199||-||Nikon D7100|
|Pentax KP« »||-||82/100||5/5||-||4.5/5||Jan 2017||1,099||Pentax KP|
|Pentax K-70« »||-||79/100||4.5/5||4/5||4.5/5||Jun 2016||649||Pentax K-70|
|Pentax K-3 II« »||-||-||5/5||4.5/5||5/5||Apr 2015||1,099||Pentax K-3 II|
|Pentax K-5« »||-||83/100||5/5||4.5/5||4.5/5||Sep 2010||1,099||-||Pentax K-5|
|Sony A6500« »||+ +||85/100||4.5/5||5/5||4.5/5||Oct 2016||1,399||Sony A6500|
|Sony A7 II« »||+||82/100||4.5/5||5/5||5/5||Nov 2014||1,999||-||Sony A7 II|
|Sony A77 II« »||-||80/100||4.5/5||4/5||5/5||May 2014||1,199||Sony A77 II|
|Sony A99« »||-||84/100||4.5/5||o||4.5/5||Sep 2012||2,799||-||Sony A99|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (-) not available.|
The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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? 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 7D II vs Pentax K-3 II
- Canon 800D vs Pentax K-3
- Canon M10 vs Sony A77 II
- Canon M50 vs Sony A77 II
- Fujifilm X-T3 vs Pentax K-3 II
- Nikon D5600 vs Pentax K-3
- Nikon D5600 vs Sony A77 II
- Nikon D7200 vs Sony A77 II
- Nikon D750 vs Pentax K-3 II
- Olympus E-M1 II vs Pentax K-3
- Olympus E-M5 II vs Sony A77 II
- Panasonic GX80 vs Pentax K-3 II
Specifications: Pentax K-3 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-3||Sony A77|
|Camera Type||Digital single lens reflex||Digital single lens reflex|
|Camera Lens||Pentax K mount lenses||Sony A mount lenses|
|Launch Date||October 2013||August 2011|
|Launch Price||USD 1299||USD 1399|
|Sensor Specs||Pentax K-3||Sony A77|
|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||100-51200 ISO||100-16000 ISO|
|ISO Boost||no Enhancement||50-25600 ISO|
|Image Processor||PRIME III||BIONZ X|
|DXO Sensor Quality (score)||80||78|
|DXO Color Depth (bits)||23.7||24.0|
|DXO Dynamic Range (EV)||13.4||13.2|
|DXO Low Light (ISO)||1216||801|
|Screen Specs||Pentax K-3||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||3.2 inch||3.0 inch|
|LCD Resolution||1037k dots||921k dots|
|LCD Attachment||Fixed screen||Fully flexible screen|
|Shooting Specs||Pentax K-3||Sony A77|
|Autofocus System||Phase-detect AF||Phase-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000/s||1/8000/s|
|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||Build-in Flash||Build-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||Sony A77|
|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||Headphone port|
|Wifi Support||no Wifi||no Wifi|
|Body Specs||Pentax K-3||Sony A77|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Type||D-LI90 power pack||NP-FM500H power pack|
|Battery Life (CIPA)||560 shots per charge||470 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)||732 g (25.8 oz)|
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