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Sony A7 II versus Pentax K-3 II

The Sony Alpha A7 II and the Pentax K-3 II are two enthusiast cameras that were officially introduced, respectively, in November 2014 and April 2015. The A7 II is a mirrorless interchangeable lens camera, while the K-3 II is a DSLR. The cameras are based on a full frame (A7 II) and an APS-C (K-3 II) sensor. The Sony has a resolution of 24 megapixel, whereas the Pentax provides 24.1 MP. Read on to find out how these two cameras compare with respect to their size, their sensors, their features, and their reception by expert reviewers.

Body comparison: Sony A7 II vs Pentax K-3 II

The physical size and weight of the Sony A7 II and the Pentax K-3 II are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All size dimensions are rounded to the nearest millimeter. If you prefer, you can also use the toggle button to switch to a comparison in percentage terms (in this case, the camera on the left side – the A7 II – represents the basis for the calculations across all the size and weight measures).

Compare Sony A7 II vs Pentax K-3 II
Compare A7 II versus K-3 II top
Compare A7 II and K-3 II rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-3 II is notably larger (7 percent) than the Sony A7 II. Moreover, the K-3 II is markedly heavier (34 percent) than the A7 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.

Concerning battery life, the A7 II gets 350 shots out of its NP-FW50 battery, while the K-3 II can take 720 images on a single charge of its D-LI90 power pack.

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, 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.

Camera Body Specifications
  Camera
Model
Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(yes/no)
Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Sony A7 II» 5.0 in 3.8 in 2.4 in 21.1 oz 350 Y Nov 2014 1,999- i Sony A7 II
Pentax K-3 II« 5.2 in 3.9 in 3.0 in 28.2 oz 720 Y Apr 2015 1,099 i i Pentax K-3 II
Canon 80D« » 5.5 in 4.1 in 3.1 in 25.8 oz 960 Y Feb 2016 1,199 i i Canon 80D
Panasonic GH5« » 5.5 in 3.9 in 3.4 in 25.6 oz 410 Y Jan 2017 1,999 i i Panasonic GH5
Pentax KP« » 5.2 in 4.0 in 3.0 in 24.8 oz 390 Y Jan 2017 1,099 i i Pentax KP
Pentax K-70« » 5.0 in 3.7 in 2.9 in 24.3 oz 410 Y Jun 2016 649 i i Pentax K-70
Pentax K-3« » 5.2 in 3.9 in 3.0 in 28.2 oz 560 Y Oct 2013 1,299- i Pentax K-3
Pentax K-5« » 5.2 in 3.8 in 2.9 in 26.8 oz 740 Y Sep 2010 1,099- i Pentax K-5
Sony A7 III« » 5.0 in 3.8 in 2.9 in 22.9 oz 610 Y Feb 2018 1,999 i i Sony A7 III
Sony A7R III« » 5.0 in 3.8 in 2.9 in 22.9 oz 650 Y Oct 2017 3,199 i i Sony A7R III
Sony A9« » 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i Sony A9
Sony A7R II« » 5.0 in 3.8 in 2.4 in 22.0 oz 290 Y Jun 2015 3,199- i Sony A7R II
Sony A7S II« » 5.0 in 3.8 in 2.4 in 22.1 oz 370 Y Sep 2015 2,999 i i Sony A7S II
Sony A7« » 5.0 in 3.7 in 1.9 in 16.7 oz 340 Y Oct 2013 1,699- i Sony A7
Sony A7R« » 5.0 in 3.7 in 1.9 in 16.4 oz 340 Y Oct 2013 2,299- i Sony A7R
Sony A77« » 5.6 in 4.1 in 3.2 in 25.8 oz 470 Y Aug 2011 1,999- i Sony A77
Sony A850« » 6.1 in 4.6 in 3.2 in 31.6 oz 880 Y Aug 2009 1,999- i Sony A850

Any camera purchase will naturally be influenced heavily by the price. 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-3 II was launched at a markedly lower price (by 45 percent) than the A7 II, 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.

 

Sensor comparison: Sony A7 II vs Pentax K-3 II

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 more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A7 II features a full frame sensor and the Pentax K-3 II an APS-C sensor. The sensor area in the K-3 II is 57 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

In terms of underlying technology, both cameras are build around CMOS sensors.

Sony A7 II and Pentax K-3 II sensor measures

Despite having a smaller sensor, the K-3 II offers a slightly higher resolution of 24.1 megapixel, compared with 24 MP of the A7 II. 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 II). However, it should be noted that the K-3 II is a somewhat more recent model (by 5 months) than the A7 II, 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 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).

A7 II versus K-3 II MP

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"). Of the two cameras under review, the A7 II has a notably higher overall DXO score than the K-3 II (overall score 10 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 1.3 bits higher color depth, and 1.1 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.

Sensor Characteristics
  Camera
Model
Sensor
Class
Resolution
(MP)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Camera
Model
Sony A7 II» Full Frame 24.0 6000 40001080/60p24.913.6244990Sony A7 II
Pentax K-3 II« APS-C 24.1 6016 40001080/60i23.613.6110680Pentax K-3 II
Canon 80D« » APS-C 24.0 6000 40001080/60p23.613.2113579Canon 80D
Panasonic GH5« » Four Thirds 20.2 5184 38884K/60p23.913.080777Panasonic GH5
Pentax KP« » APS-C 24.1 6016 40001080/60i----Pentax KP
Pentax K-70« » APS-C 24.0 6000 40001080/60i----Pentax K-70
Pentax K-3« » APS-C 24.1 6016 40001080/60i23.713.4121680Pentax K-3
Pentax K-5« » APS-C 16.1 4928 32641080/25p23.714.1116282Pentax K-5
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
Sony A7R III« » Full Frame 42.2 7952 53044K/30p26.014.73523100Sony A7R III
Sony A9« » Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
Sony A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498Sony A7R II
Sony A7S II« » Full Frame 12.0 4240 28324K/30p23.613.3299385Sony A7S II
Sony A7« » Full Frame 24.0 6000 40001080/60p24.814.2224890Sony A7
Sony A7R« » Full Frame 36.2 7360 49121080/60p25.614.1274695Sony A7R
Sony A77« » APS-C 24.0 6000 40001080/60p24.013.280178Sony A77
Sony A850« » Full Frame 24.4 6048 4032-23.812.2141579Sony A850

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A7 II provides a higher frame rate than the K-3 II. It can shoot video footage at 1080/60p, while the Pentax is limited to 1080/60i.

 

Feature comparison: Sony A7 II vs Pentax K-3 II

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A7 II 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 adjacent table lists some of the other core features of the Sony A7 II and Pentax K-3 II along with similar information for a selection of comparators. The full specs-sheets can be found in the camera manual or in the dpreview camera hub.

Core Features
  Camera
Model
Viewfinder
(Type or
'000 dots)
Control
Panel
(yes/no)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(yes/no)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec)
Build-in
Flash
(yes/no)
Build-in
Image
Stab
Camera
Model
Sony A7 II»2400 n 3.0 1230 tilting n 8000 5.0 n Y Sony A7 II
Pentax K-3 II«optical Y 3.2 1037 fixed n 8000 8.3 n Y Pentax K-3 II
Canon 80D« »optical Y 3.0 1040 swivel Y 8000 7.0 Y n Canon 80D
Panasonic GH5« »3680 n 3.2 1620 swivel Y 8000 12.0 n Y Panasonic GH5
Pentax KP« »optical n 3.0 921 tilting n 6000 7.0 Y Y Pentax KP
Pentax K-70« »optical n 3.0 921 swivel n 6000 6.0 Y Y Pentax K-70
Pentax K-3« »optical Y 3.2 1037 fixed n 8000 8.3 Y Y Pentax K-3
Pentax K-5« »optical Y 3.0 921 fixed n 8000 7.0 Y Y Pentax K-5
Sony A7 III« »2359 n 3.0 922 tilting Y 8000 10.0 n Y Sony A7 III
Sony A7R III« »3686 n 3.0 1440 tilting Y 8000 10.0 n Y Sony A7R III
Sony A9« »3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
Sony A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7R II
Sony A7S II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7S II
Sony A7« »2400 n 3.0 1230 tilting n 8000 5.0 n n Sony A7
Sony A7R« »2400 n 3.0 1230 tilting n 8000 4.0 n n Sony A7R
Sony A77« »2359 Y 3.0 921 full-flex n 8000 12.0 Y Y Sony A77
Sony A850« »optical Y 3.0 922 fixed n 8000 3.0 n Y Sony A850

One feature that is present on the K-3 II, but is missing on the A7 II is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The A7 II writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the K-3 II uses SDXC cards. The K-3 II features dual card slots, which can be very useful in case a memory card fails. In contrast, the A7 II only has one slot.

Input-Output Connections
  Camera
Model
Hotshoe
Port
Internal
Microphone
Internal
Speaker
Microphone
Port
Headphone
Port
HDMI
Port
USB
Type
WiFi
Support
NFC
Support
Bluetooth
Support
Camera
Model
Sony A7 II»YstereomonoYYmicro2.0YY-Sony A7 II
Pentax K-3 II«YmonomonoYYmini3.0---Pentax K-3 II
Canon 80D« »YstereomonoYYmini2.0YY-Canon 80D
Panasonic GH5« »YstereomonoYYfull3.1Y-YPanasonic GH5
Pentax KP« »YstereomonoY--2.0Y--Pentax KP
Pentax K-70« »YstereomonoY-mini2.0Y--Pentax K-70
Pentax K-3« »YmonomonoYYmini3.0---Pentax K-3
Pentax K-5« »YstereomonoY-mini2.0---Pentax K-5
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
Sony A7R III« »YstereomonoYYmicro3.1YYYSony A7R III
Sony A9« »YstereomonoYYmicro2.0YYYSony A9
Sony A7R II« »YstereomonoYYmicro2.0YY-Sony A7R II
Sony A7S II« »YstereomonoYYmicro2.0YY-Sony A7S II
Sony A7« »YstereomonoYYmicro2.0YY-Sony A7
Sony A7R« »YstereomonoYYmicro2.0YY-Sony A7R
Sony A77« »YstereomonoY-mini2.0---Sony A77
Sony A850« »Y----mini2.0---Sony A850

The K-3 II is a current model that online retailers, such as amazon, will have in stock. In contrast, the A7 II has been discontinued (but it can be found pre-owned on eBay). As a replacement in the same line of cameras, the A7 II was succeeded by the Sony A7 III.

Review summary: Sony A7 II vs Pentax K-3 II

So what is the bottom line? Is the Sony A7 II better than the Pentax K-3 II or vice versa? Below is a summary of the relative strengths of each of the two contestants.

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Arguments in favor of the Sony Alpha A7 II:

  • 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 assessment.
  • Richer colors: Generates images with noticeably better colors (1.3 bits more color depth).
  • Better low-light sensitivity: Requires less light for good images (1.1 stops ISO advantage).
  • Better video: Provides higher movie framerates (1080/60p versus 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: Is lighter (by 201g or 25 percent) and hence easier to carry around.
  • More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
  • Easier file upload: Has wifi build 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 November 2014).

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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: Features a control panel on top to check 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: Gets more shots (720 versus 350) out of 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 affordable: Was introduced into a lower priced category (45 percent cheaper at launch).
  • More modern: Was introduced somewhat (5 months) more recently.

If the number of relative strengths (bullet points above) is taken as a guide, the A7 II emerges as the winner of the contest (13 : 11 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.

A7 II 13:11 K-3 II

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the A7 II or the K-3 II handle or perform in practice. 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 adjacent table relays the overall verdicts of several of the most popular camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). The full reviews are available by clicking on the site logo in the table header.

Review Scores
  Camera
Model
cameralabs dpreview ephotozine imaging-resource photographyblog Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Sony A7 II»Rec82/1004.5/55/55/5 Nov 2014 1,999- i Sony A7 II
Pentax K-3 II«--5/54.5/55/5 Apr 2015 1,099 i i Pentax K-3 II
Canon 80D« »HiRec84/1004.5/54.5/54.5/5 Feb 2016 1,199 i i Canon 80D
Panasonic GH5« »HiRec85/1004.5/55/55/5 Jan 2017 1,999 i i Panasonic GH5
Pentax KP« »-82/1005/5-4.5/5 Jan 2017 1,099 i i Pentax KP
Pentax K-70« »-79/1004.5/54/54.5/5 Jun 2016 649 i i Pentax K-70
Pentax K-3« »-83/1005/54.5/55/5 Oct 2013 1,299- i Pentax K-3
Pentax K-5« »-83/1005/54.5/54.5/5 Sep 2010 1,099- i Pentax K-5
Sony A7 III« »HiRec89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
Sony A7R III« »HiRec90/1004.5/55/55/5 Oct 2017 3,199 i i Sony A7R III
Sony A9« »HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
Sony A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i Sony A7R II
Sony A7S II« »Rec-4.5/55/55/5 Sep 2015 2,999 i i Sony A7S II
Sony A7« »HiRec80/1005/54.5/55/5 Oct 2013 1,699- i Sony A7
Sony A7R« »HiRec82/1004.5/55/55/5 Oct 2013 2,299- i Sony A7R
Sony A77« »91/10081/100-4.5/55/5 Aug 2011 1,999- i Sony A77
Sony A850« »-75/100-4/54.5/5 Aug 2009 1,999- i Sony A850

The review scores listed above should be treated with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. 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. 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 you do not see the camera that you are looking for, please send me an email, and I will try to locate and add the respective data to the application.

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