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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 announced, 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 sensor. The Sony has a resolution of 24 megapixel, whereas the Pentax provides 24.1 MP.

Body comparison

An illustration of the physical size and weight of the Sony A7 II and the Pentax K-3 II is provided in the side-by-side display below. Three successive views from the front, the top, and the rear are shown. All width, height and depth dimensions are rounded to the nearest millimeter. You can also use the toggle button 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 – the A7 II – represents 100 percent across all the size and weight measures).

Sony A7 II vs Pentax K-3 II front
A7 II versus K-3 II top view
A7 II and K-3 II rear side
Body view (A7 II on the left)

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 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
Camera Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(y/n)
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Sony A7 II (⇒ rgt) 127 mm 96 mm 60 mm 599 g 350 YES 2014 1,999discont. check
Pentax K-3 II (⇒ lft) 131 mm 100 mm 77 mm 800 g 720 YES 2015 1,099 latest check
Olympus E-M1 II (⇒ lft | rgt) 134 mm 91 mm 67 mm 574 g 440 YES 2016 1,999 latest check
Panasonic GX8 (⇒ lft | rgt) 133 mm 78 mm 63 mm 487 g 330 YES 2015 1,199discont. 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 1,299discont. check
Sony A7 III (⇒ lft | rgt) 127 mm 96 mm 74 mm 650 g 610 YES 2018 1,999 latest check
Sony A9 (⇒ lft | rgt) 127 mm 96 mm 63 mm 673 g 650 YES 2017 4,499 latest check
Sony A7R III (⇒ lft | rgt) 127 mm 96 mm 74 mm 650 g 650 YES 2017 3,199 latest check
Sony A7R II (⇒ lft | rgt) 127 mm 96 mm 60 mm 625 g 290 YES 2015 3,199discont. check
Sony A7S II (⇒ lft | rgt) 127 mm 96 mm 60 mm 627 g 370 YES 2015 2,999 latest check
Sony RX10 II (⇒ lft | rgt) 129 mm 88 mm 102 mm 813 g 400 YES 2015 1,299discont. check
Sony A77 II (⇒ lft | rgt) 143 mm 104 mm 81 mm 647 g 480 YES 2014 1,199 latest check
Sony A7 (⇒ lft | rgt) 127 mm 94 mm 48 mm 474 g 340 YES 2013 1,699discont. check
Sony A7R (⇒ lft | rgt) 127 mm 94 mm 48 mm 465 g 340 YES 2013 2,299discont. check
Sony A77 (⇒ lft | rgt) 143 mm 104 mm 81 mm 732 g 470 YES 2011 1,999discont. 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 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

The size of the imaging sensor is a crucial determinant 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. 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 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.

Sony A7 II and Pentax K-3 II sensor measures
Sensor size

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
Sensor resolution

For most cameras, data on sensor performance has been reported by DXO Mark. 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 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 Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Sony A7 II (⇒ rgt) Full Frame 24.0 6000 4000 1080/60p 24.9 13.6 2449 90
Pentax K-3 II (⇒ lft) APS-C 24.1 6016 4000 1080/60i 23.6 13.6 1106 80
Olympus E-M1 II (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/30p 23.7 12.8 1312 80
Panasonic GX8 (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/30p 23.5 12.6 806 75
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 A7 III (⇒ lft | rgt) Full Frame 24.0 6000 4000 4K/30p 25.0 14.7 3730 96
Sony A9 (⇒ lft | rgt) Full Frame 24.0 6000 4000 4K/30p 24.9 13.3 3517 92
Sony A7R III (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 26.0 14.7 3523 100
Sony A7R II (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 26.0 13.9 3434 98
Sony A7S II (⇒ lft | rgt) Full Frame 12.0 4240 2832 4K/30p 23.6 13.3 2993 85
Sony RX10 II (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 23.0 12.6 531 70
Sony A77 II (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p - - - -
Sony A7 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.8 14.2 2248 90
Sony A7R (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60p 25.6 14.1 2746 95
Sony A77 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24 13.2 801 78

Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, 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

Beyond body and sensor, cameras can and do differ across a range 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. If you need more detail on the specs, you can find comprehensive listings, for example, in the dpreview camera hub.

Core Features
Camera Viewfinder
(Type or
'000 dots)
Control
Panel
(Y/n)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(Y/n)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec))
Build-in
Flash
(GN)
Build-in
Image
Stab
Sony A7 II (⇒ rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no YES
Pentax K-3 II (⇒ lft) optical YES 3.2 1037 fixed no 8000 8.3 no YES
Olympus E-M1 II (⇒ lft | rgt) 2360 no 3.0 1037 swivel YES 8000 18.0 no YES
Panasonic GX8 (⇒ lft | rgt) 2360 no 3.0 1040 swivel YES 8000 10.0 no YES
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 A7 III (⇒ lft | rgt) 2359 no 3.0 922 tilting YES 8000 10 no YES
Sony A9 (⇒ lft | rgt) 3686 no 3.0 1440 tilting YES 8000 20.0 no YES
Sony A7R III (⇒ lft | rgt) 3686 no 3.0 1440 tilting YES 8000 10.0 no YES
Sony A7R II (⇒ lft | rgt) 2400 no 3.0 1229 tilting no 8000 5.0 no YES
Sony A7S II (⇒ lft | rgt) 2400 no 3.0 1229 tilting no 8000 5.0 no YES
Sony RX10 II (⇒ lft | rgt) 2359 YES 3.0 1229 tilting no 3200 14.0 10.2 YES
Sony A77 II (⇒ lft | rgt) 2359 YES 3.0 1229 full-flex no 8000 12.0 12 YES
Sony A7 (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no no
Sony A7R (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 4.0 no no
Sony A77 (⇒ lft | rgt) 2359 YES 3.0 921 full-flex no 8000 12.0 12 YES

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.

Summary

So how do things add up? Is there a clear favorite between the Sony A7 II and the Sony A7 II? Below is a summary of the relative strengths of each of the two contestants.


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Advantages 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 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: 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.
  • More heavily discounted: Has been on the market for longer (launched in November 2014).

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Arguments in favor 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 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.
  • 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 (11 : 9 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.

A7 II 11:09 K-3 II

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 A7 II and the K-3 II in practical situations. 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 hands-on reviews by experts are important. The following table reports the overall rankings of the cameras as published by some of the major camera review sites. You can find the full text of the reviews, respectively, at cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.

Review scores
Camera camera
labs
dp
review
ephoto
zine
imaging
resource
photography
blog
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Sony A7 II (⇒ rgt) Rec 82/100 Silver 4.5/5 5/5 5/5 2014 1,999discont. check
Pentax K-3 II (⇒ lft) - - 5/5 4.5/5 5/5 2015 1,099 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
Panasonic GX8 (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 4.5/5 2015 1,199discont. 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 1,299discont. check
Sony A7 III (⇒ lft | rgt) HiRec 89/100 Gold 5/5 .. 5/5 2018 1,999 latest check
Sony A9 (⇒ lft | rgt) HiRec 89/100 Gold 5/5 5/5 5/5 2017 4,499 latest check
Sony A7R III (⇒ lft | rgt) HiRec 90/100 Gold 4.5/5 5/5 5/5 2017 3,199 latest check
Sony A7R II (⇒ lft | rgt) HiRec 90/100 Gold 5/5 4.5/5 5/5 2015 3,199discont. check
Sony A7S II (⇒ lft | rgt) Rec - 4.5/5 5/5 5/5 2015 2,999 latest check
Sony RX10 II (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 4.5/5 4/5 2015 1,299discont. check
Sony A77 II (⇒ lft | rgt) - 80/100 Silver 4.5/5 4/5 5/5 2014 1,199 latest check
Sony A7 (⇒ lft | rgt) HiRec 80/100 Silver 5/5 4.5/5 5/5 2013 1,699discont. check
Sony A7R (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 5/5 5/5 2013 2,299discont. check
Sony A77 (⇒ lft | rgt) 91/100 81/100 Silver - 4.5/5 5/5 2011 1,999discont. check

The above review scores should be interpreted with care, though. The ratings are only valid when refering to cameras in the same category and of the same age. 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. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Other comparisons

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. If you do not see the camera that you are looking for, kindly get in touch, and I will try to locate and add the respective data to the application.

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