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Sony A77 II versus Pentax K-3

The Sony Alpha SLT-A77 II and the Pentax K-3 are two enthusiast cameras that were announced, respectively, in May 2014 and October 2013. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with 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 A77 II and the Pentax K-3 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. 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 – the A77 II – represents 100 percent across all the size and weight measures).

Sony A77 II vs Pentax K-3 front
A77 II versus K-3 top view
A77 II and K-3 rear side
Body view (A77 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 is notably smaller (12 percent) than the Sony A77 II. However, the K-3 is markedly heavier (24 percent) than the A77 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
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 A77 II (⇒ rgt) 143 mm 104 mm 81 mm 647 g 480 YES 2014 1,199 latest check
Pentax K-3 (⇒ lft) 131 mm 100 mm 77 mm 800 g 560 YES 2013 1,299discont. check
Nikon D7200 (⇒ lft | rgt) 136 mm 107 mm 76 mm 765 g 1110 YES 2015 1,199discont. check
Panasonic GX8 (⇒ lft | rgt) 133 mm 78 mm 63 mm 487 g 330 YES 2015 1,199 latest 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 II (⇒ lft | rgt) 131 mm 100 mm 77 mm 800 g 720 YES 2015 1,099 latest check
Sony A9 (⇒ lft | rgt) 127 mm 96 mm 63 mm 673 g 650 YES 2017 4,499 latest check
Sony A6500 (⇒ lft | rgt) 120 mm 67 mm 53 mm 453 g 350 YES 2016 1,399 latest check
Sony RX10 II (⇒ lft | rgt) 129 mm 88 mm 102 mm 813 g 400 YES 2015 1,299discont. check
Sony A7 II (⇒ lft | rgt) 127 mm 96 mm 60 mm 599 g 350 YES 2014 1,999 latest check
Sony RX10 (⇒ lft | rgt) 129 mm 88 mm 102 mm 813 g 420 YES 2013 1,299discont. check
Sony A99 (⇒ lft | rgt) 147 mm 111 mm 78 mm 812 g 500 YES 2012 2,799discont. 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 A77 II was somewhat cheaper (by 8 percent) than the K-3 at launch, but both cameras fall into the same price category. 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 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 generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have 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 are more costly to manufacture and tent to lead to bigger and heavier cameras 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.

Sony A77 II and Pentax K-3 sensor measures
Sensor size

While the two cameras under review share the same sensor size, the K-3 offers a slightly higher resolution of 24.1 megapixel, compared with 24 MP of the A77 II. This megapixel 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 II). Moreover, it should be noted, that the A77 II is a somewhat more recent model (by 6 months) than the K-3, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of individual pixels. 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.

A77 II versus K-3 MP
Sensor resolution

Consistent information on actual sensor performance is available from DXO Mark for most 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. 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 A77 II (⇒ rgt) APS-C 24.0 6000 4000 1080/60p - - - -
Pentax K-3 (⇒ lft) APS-C 24.1 6016 4000 1080/60i 23.7 13.4 1216 80
Nikon D7200 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24.5 14.6 1333 87
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 II (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i 23.6 13.6 1106 80
Sony A9 (⇒ lft | rgt) Full Frame 24.0 6000 4000 4K/30p 24.9 13.3 3517 92
Sony A6500 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p 24.5 13.7 1405 85
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 RX10 (⇒ lft | rgt) 1-inch 20.0 5472 3648 1080/60p 22.9 12.6 474 69
Sony A99 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 25.0 14.0 1555 89
Sony A77 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24 13.2 801 78

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 II provides a higher frame rate than the K-3. It can shoot video footage at 1080/60p, while the Pentax is limited to 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A77 II 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 following table reports on some other key feature differences and similarities of the Sony A77 II, the Pentax K-3, and comparable cameras. The full specs-sheets can be found in the camera manual or, 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 A77 II (⇒ rgt) 2359 YES 3.0 1229 full-flex no 8000 12.0 12 YES
Pentax K-3 (⇒ lft) optical YES 3.2 1037 fixed no 8000 8.3 13 YES
Nikon D7200 (⇒ lft | rgt) optical YES 3.2 1229 fixed no 8000 6.0 12 no
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 II (⇒ lft | rgt) optical YES 3.2 1037 fixed no 8000 8.3 no YES
Sony A9 (⇒ lft | rgt) 3686 no 3.0 1440 tilting YES 8000 20.0 no YES
Sony A6500 (⇒ lft | rgt) 2300 no 3.0 922 tilting YES 4000 11.0 6 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 RX10 (⇒ lft | rgt) 1440 YES 3.0 1229 tilting no 3200 10.0 10.2 YES
Sony A99 (⇒ lft | rgt) 2359 YES 3.0 1229 full-flex no 8000 6.0 no YES
Sony A77 (⇒ lft | rgt) 2359 YES 3.0 921 full-flex no 8000 12.0 12 YES

The A77 II is a current model that online retailers, such as amazon, will have in stock. In contrast, the K-3 has been discontinued (but it can be found pre-owned on ebay). As a replacement in the same line of cameras, the K-3 was succeeded by the Pentax K-3 II.

Summary

So how do things add up? Is the Sony A77 II better than the Pentax K-3 or vice versa? A synthesis of the relative strong points of each of the models is listed below.


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Reasons to prefer the Sony Alpha SLT-A77 II:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • 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 (1229k vs 1037k dots).
  • More flexible LCD: Has full-flex screen for odd-angle shots in portrait or landscape orientation.
  • Faster burst: Shoots at higher frequency (12 vs 8.3 flaps/sec) to capture the decisive moment.
  • Less heavy: Is lighter (by 153g or 19 percent) and hence easier to carry around.
  • More modern: Is somewhat more recent (announced 6 months after the K-3).

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Arguments in favor of the Pentax K-3:

  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • 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 compact: Is smaller (131x100mm vs 143x104mm) and will fit more readily into a bag.
  • Longer lasting: Gets more shots (560 versus 480) out of a single battery charge.
  • More heavily discounted: Has been on the market for longer (launched in October 2013).

If the number of relative strengths (bullet points above) is taken as a guide, the A77 II emerges as the winner of the contest (8 : 6 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.

A77 II 08:06 K-3

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the A77 II and the K-3 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 hands-on reviews by experts are important. The adjacent table relays the overall verdicts of several of the most popular camera review sites. The detailed reviews can be accessed, respectively, on the websites of 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 A77 II (⇒ rgt) - 80/100 Silver 4.5/5 4/5 5/5 2014 1,199 latest check
Pentax K-3 (⇒ lft) - 83/100 Gold 5/5 4.5/5 5/5 2013 1,299discont. check
Nikon D7200 (⇒ lft | rgt) HiRec 84/100 Silver 4.5/5 4/5 4.5/5 2015 1,199discont. check
Panasonic GX8 (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 4.5/5 2015 1,199 latest 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 II (⇒ lft | rgt) - - 5/5 4.5/5 5/5 2015 1,099 latest check
Sony A9 (⇒ lft | rgt) .. 89/100 Gold 5/5 5/5 5/5 2017 4,499 latest check
Sony A6500 (⇒ lft | rgt) HiRec 85/100 Silver 4.5/5 5/5 4.5/5 2016 1,399 latest check
Sony RX10 II (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 4.5/5 4/5 2015 1,299discont. check
Sony A7 II (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 5/5 2014 1,999 latest check
Sony RX10 (⇒ lft | rgt) Rec 80/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,299discont. check
Sony A99 (⇒ lft | rgt) - 84/100 Gold 4.5/5 reviewed 4.5/5 2012 2,799discont. 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 comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Other comparisons

In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored. If you cannot find the camera you are interested in, please send me an email, and I will try to add information on that model to the database.

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