Pentax K-3 II versus Sony A7
The Pentax K-3 II and the Sony Alpha A7 are two enthusiast cameras that were announced, respectively, in April 2015 and October 2013. The K-3 II is a DSLR, while the A7 is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (K-3 II) and a full frame sensor. The Pentax has a resolution of 24.1 megapixel, whereas the Sony provides 24 MP.
An illustration of the physical size and weight of the Pentax K-3 II and the Sony A7 is provided in the side-by-side display below. Three successive views from the front, the top, and the rear are shown. All size dimensions are rounded to the nearest millimeter. You can also toggle the display to switch to a percentage comparison if you prefer that the measures are being expressed in relative terms (in this case, the camera on the left side – the K-3 II – represents the basis for the calculations across all the size and weight measures).
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7 is somewhat smaller (9 percent) than the Pentax K-3 II. Moreover, the A7 is substantially lighter (41 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 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 comparisons there.
|Camera Body Specifications
|Pentax K-3 II (⇒ rgt)||131 mm||100 mm||77 mm||800 g||720||YES||2015||1,099||latest||check|
|Sony A7 (⇒ lft)||127 mm||94 mm||48 mm||474 g||340||YES||2013||1,699||discont.||check|
|Canon 80D (⇒ lft | rgt)||139 mm||105 mm||79 mm||730 g||960||YES||2016||1,199||latest||check|
|Nikon D7200 (⇒ lft | rgt)||136 mm||107 mm||76 mm||765 g||1110||YES||2015||1,199||discont.||check|
|Nikon D610 (⇒ lft | rgt)||141 mm||113 mm||82 mm||850 g||900||YES||2013||1,999||latest||check|
|Olympus E-M1 II (⇒ lft | rgt)||134 mm||91 mm||67 mm||574 g||440||YES||2016||1,999||latest||check|
|Olympus PEN-F (⇒ lft | rgt)||125 mm||72 mm||37 mm||427 g||330||no||2016||1,199||latest||check|
|Olympus E-M5 II (⇒ lft | rgt)||124 mm||85 mm||45 mm||469 g||310||YES||2015||1,099||latest||check|
|Panasonic GX8 (⇒ lft | rgt)||133 mm||78 mm||63 mm||487 g||330||YES||2015||1,199||latest||check|
|Panasonic GH4 (⇒ lft | rgt)||133 mm||93 mm||84 mm||560 g||500||YES||2014||1,499||discont.||check|
|Pentax KP (⇒ lft | rgt)||132 mm||101 mm||76 mm||703 g||390||YES||2017||1,099||latest||check|
|Pentax K-70 (⇒ lft | rgt)||126 mm||93 mm||74 mm||688 g||410||YES||2016||649||latest||check|
|Pentax K-3 (⇒ lft | rgt)||131 mm||100 mm||77 mm||800 g||560||YES||2013||1,299||discont.||check|
|Sony RX10 II (⇒ lft | rgt)||129 mm||88 mm||102 mm||813 g||400||YES||2015||1,299||discont.||check|
|Sony A7 II (⇒ lft | rgt)||127 mm||96 mm||60 mm||599 g||350||YES||2014||1,999||latest||check|
|Sony A7S (⇒ lft | rgt)||127 mm||94 mm||48 mm||489 g||380||YES||2014||2,499||discont.||check|
|Sony A7R (⇒ lft | rgt)||127 mm||94 mm||48 mm||465 g||340||YES||2013||2,299||discont.||check|
The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The K-3 II was launched at a markedly lower price (by 35 percent) than the A7, 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 sensor inside a digital camera is one of the key determinants 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. 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 K-3 II features an APS-C sensor and the Sony A7 a full frame sensor. The sensor area in the A7 is 133 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 K-3 II offers a higher resolution of 24.1 megapixel, compared with 24 MP of the Sony A7. This megapixel 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 5.97μm for the A7). However, it should be noted that the K-3 II is a somewhat more recent model (by 1 year and 6 months) than the A7, and its sensor might have benefitted from technological advances during this time that partly offset its pixel-size disadvantage. 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 A7, 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).
Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. This service is based on lab testing and assigns an overall score to each camera sensor, as well as ratings for dynamic range ("DXO Landscape"), color depth ("DXO Portrait"), and low-light sensitivity ("DXO Sports"). Of the two cameras under consideration, the A7 has a markedly higher DXO score than the K-3 II (overall score 10 points higher), which will translate into better image quality. The advantage is based on 1.2 bits higher color depth, 0.6 EV in additional dynamic range, and 1 stops in additional low light sensitivity. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
|Pentax K-3 II (⇒ rgt)||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
|Sony A7 (⇒ lft)||Full Frame||24.0||6000||4000||1080/60p||24.8||14.2||2248||90|
|Canon 80D (⇒ lft | rgt)||APS-C||24.0||6000||4000||1080/60p||23.6||13.2||1135||79|
|Nikon D7200 (⇒ lft | rgt)||APS-C||24.0||6000||4000||1080/60p||24.5||14.6||1333||87|
|Nikon D610 (⇒ lft | rgt)||Full Frame||24.2||6016||4016||1080/30p||25.1||14.4||2925||94|
|Olympus E-M1 II (⇒ lft | rgt)||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|Olympus PEN-F (⇒ lft | rgt)||Four Thirds||20.2||5184||3888||1080/60p||23.1||12.4||894||74|
|Olympus E-M5 II (⇒ lft | rgt)||Four Thirds||15.9||4608||3456||1080/60p||23.0||12.5||842||73|
|Panasonic GX8 (⇒ lft | rgt)||Four Thirds||20.2||5184||3888||4K/30p||23.5||12.6||806||75|
|Panasonic GH4 (⇒ lft | rgt)||Four Thirds||15.9||4608||3456||4K/30p||23.2||12.8||791||74|
|Pentax KP (⇒ lft | rgt)||APS-C||24.1||6016||4000||1080/60i||-||-||-||-|
|Pentax K-70 (⇒ lft | rgt)||APS-C||24.0||6000||4000||1080/60i||-||-||-||-|
|Pentax K-3 (⇒ lft | rgt)||APS-C||24.1||6016||4000||1080/60i||23.7||13.4||1216||80|
|Sony RX10 II (⇒ lft | rgt)||1-inch||20.0||5472||3648||4K/30p||23.0||12.6||531||70|
|Sony A7 II (⇒ lft | rgt)||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|Sony A7S (⇒ lft | rgt)||Full Frame||12.0||4240||2832||1080/60p||23.9||13.2||3702||87|
|Sony A7R (⇒ lft | rgt)||Full Frame||36.2||7360||4912||1080/60p||25.6||14.1||2746||95|
Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A7 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 A7 has an electronic viewfinder (2400k 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 table below summarizes some of the other core capabilities of the Pentax K-3 II and Sony A7 in connection with corresponding information for a sample of similar cameras. The full specs-sheets can be found in the camera manual or, for example, in the dpreview camera hub.
|Pentax K-3 II (⇒ rgt)||optical||YES||3.2||1037||fixed||no||8000||8.3||no||YES|
|Sony A7 (⇒ lft)||2400||no||3.0||1230||tilting||no||8000||5.0||no||no|
|Canon 80D (⇒ lft | rgt)||optical||YES||3.0||1040||swivel||YES||8000||7.0||12||no|
|Nikon D7200 (⇒ lft | rgt)||optical||YES||3.2||1229||fixed||no||8000||6.0||12||no|
|Nikon D610 (⇒ lft | rgt)||optical||YES||3.2||921||fixed||no||4000||6.0||12||no|
|Olympus E-M1 II (⇒ lft | rgt)||2360||no||3.0||1037||swivel||YES||8000||18.0||no||YES|
|Olympus PEN-F (⇒ lft | rgt)||2360||no||3.0||1037||swivel||YES||8000||10.0||no||YES|
|Olympus E-M5 II (⇒ lft | rgt)||2360||no||3.0||1037||swivel||YES||8000||10.0||no||YES|
|Panasonic GX8 (⇒ lft | rgt)||2360||no||3.0||1040||swivel||YES||8000||10.0||no||YES|
|Panasonic GH4 (⇒ lft | rgt)||2359||no||3.0||1036||swivel||YES||8000||12.0||17||no|
|Pentax KP (⇒ lft | rgt)||optical||no||3.0||921||tilting||no||6000||7.0||YES||YES|
|Pentax K-70 (⇒ lft | rgt)||optical||no||3.0||921||swivel||no||6000||6.0||YES||YES|
|Pentax K-3 (⇒ lft | rgt)||optical||YES||3.2||1037||fixed||no||8000||8.3||13||YES|
|Sony RX10 II (⇒ lft | rgt)||2359||YES||3.0||1229||tilting||no||3200||14.0||10.2||YES|
|Sony A7 II (⇒ lft | rgt)||2400||no||3.0||1230||tilting||no||8000||5.0||no||YES|
|Sony A7S (⇒ lft | rgt)||2400||no||3.0||921||tilting||no||8000||5.0||no||no|
|Sony A7R (⇒ lft | rgt)||2400||no||3.0||1230||tilting||no||8000||4.0||no||no|
The K-3 II is a current model that online retailers, such as amazon, will have in stock. In contrast, the A7 has been discontinued (but it can be found pre-owned on ebay). As a replacement in the same line of cameras, the A7 was succeeded by the Sony A7 II.
So how do things add up? Is the Pentax K-3 II better than the Sony A7 or vice versa? The listing below highlights the relative strengths of the two models.
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.
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Easier setting verification: Has an LCD display on top to control shooting parameters.
- Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
- Faster burst: Shoots at higher frequency (8.3 vs 5 flaps/sec) to capture the decisive moment.
- Longer lasting: Can take more shots (720 versus 340) on a single battery charge.
- Sharper images: Has hand-shake reducing image stabilization build-in.
- More affordable: Was introduced into a lower priced category (35 percent cheaper at launch).
- More modern: Is somewhat more recent (announced 1 year and 6 months after the A7).
Reasons to prefer the Sony Alpha A7:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better image quality: Scores markedly higher (10 points) in the DXO overall evaluation.
- Richer colors: Generates noticeably more natural colors (1.2 bits more color depth).
- More dynamic range: Captures a broader range of light and dark details (0.6 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (1 stops ISO advantage).
- Better video: Provides higher movie framerates (1080/60p vs 1080/60i).
- More framing info: Has an electronic viewfinder that displays shooting data.
- More detailed LCD: Has a higher resolution rear screen (1230k vs 1037k dots).
- More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
- Less heavy: Has a lower weight (by 326g or 41 percent) and is thus easier to take along.
- More legacy lens friendly: Can use many non-native lenses via adapters.
- More heavily discounted: Has been on the market for longer (launched in October 2013).
If the count of individual advantages (bullet points above) is taken as a guide, the A7 emerges as the winner of the match-up (12 : 10 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.
In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the K-3 II and the A7 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. This is why expert reviews are important. The table below summarizes the assessments of some of the best known camera review sites. The full reviews are available, respectively, at cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.
|Pentax K-3 II (⇒ rgt)||-||-||5/5||4.5/5||5/5||2015||1,099||latest||check|
|Sony A7 (⇒ lft)||HiRec||80/100 Silver||5/5||4.5/5||5/5||2013||1,699||discont.||check|
|Canon 80D (⇒ lft | rgt)||HiRec||84/100 Silver||4.5/5||4.5/5||4.5/5||2016||1,199||latest||check|
|Nikon D7200 (⇒ lft | rgt)||HiRec||84/100 Silver||4.5/5||4/5||4.5/5||2015||1,199||discont.||check|
|Nikon D610 (⇒ lft | rgt)||HiRec||87/100 Gold||4.5/5||4.5/5||4.5/5||2013||1,999||latest||check|
|Olympus E-M1 II (⇒ lft | rgt)||HiRec||85/100 Gold||4.5/5||5/5||4.5/5||2016||1,999||latest||check|
|Olympus PEN-F (⇒ lft | rgt)||-||82/100 Silver||4.5/5||4.5/5||5/5||2016||1,199||latest||check|
|Olympus E-M5 II (⇒ lft | rgt)||HiRec||81/100 Silver||5/5||4.5/5||5/5||2015||1,099||latest||check|
|Panasonic GX8 (⇒ lft | rgt)||Rec||82/100 Silver||4.5/5||5/5||4.5/5||2015||1,199||latest||check|
|Panasonic GH4 (⇒ lft | rgt)||HiRec||85/100 Gold||5/5||5/5||5/5||2014||1,499||discont.||check|
|Pentax KP (⇒ lft | rgt)||-||82/100 Silver||5/5||-||4.5/5||2017||1,099||latest||check|
|Pentax K-70 (⇒ lft | rgt)||-||79/100 Silver||4.5/5||4/5||4.5/5||2016||649||latest||check|
|Pentax K-3 (⇒ lft | rgt)||-||83/100 Gold||5/5||4.5/5||5/5||2013||1,299||discont.||check|
|Sony RX10 II (⇒ lft | rgt)||HiRec||82/100 Gold||4.5/5||4.5/5||4/5||2015||1,299||discont.||check|
|Sony A7 II (⇒ lft | rgt)||Rec||82/100 Silver||4.5/5||5/5||5/5||2014||1,999||latest||check|
|Sony A7S (⇒ lft | rgt)||-||86/100 Gold||4.5/5||4.5/5||5/5||2014||2,499||discont.||check|
|Sony A7R (⇒ lft | rgt)||HiRec||82/100 Gold||4.5/5||5/5||5/5||2013||2,299||discont.||check|
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. It should also be noted that some of the review sites have over time altered the way they render their verdicts.
In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. An an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool. If the camera you are interested in is not available, please send me an email, and I will try to update the database with the necessary infos.
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