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Panasonic GX8 versus Pentax K-3 II

The Panasonic Lumix DMC-GX8 and the Pentax K-3 II are two enthusiast cameras that were officially introduced, respectively, in July 2015 and April 2015. The GX8 is a mirrorless interchangeable lens camera, while the K-3 II is a DSLR. The cameras are based on a Four Thirds (GX8) and an APS-C sensor. The Panasonic has a resolution of 20.2 megapixel, whereas the Pentax provides 24.1 MP.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Panasonic GX8 and the Pentax K-3 II. 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. 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 – the GX8 – represents 100 percent across all the size and weight measures).

Panasonic GX8 vs Pentax K-3 II front
GX8 versus K-3 II top view
GX8 and K-3 II rear side
Body view (GX8 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 (26 percent) than the Panasonic GX8. Moreover, the K-3 II is substantially heavier (64 percent) than the GX8. Cameras that are aimed at professionals or semi-pros tend to be a bit bulkier in order to give them the necessary environmental and shock resistance. 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)
Panasonic GX8 (⇒ rgt) 5.2 in 3.1 in 2.5 in 17.2 oz 330 YES 2015 1,199 latest check
Pentax K-3 II (⇒ lft) 5.2 in 3.9 in 3.0 in 28.2 oz 720 YES 2015 1,099 latest check
Canon 80D (⇒ lft | rgt) 5.5 in 4.1 in 3.1 in 25.8 oz 960 YES 2016 1,199 latest check
Nikon D7200 (⇒ lft | rgt) 5.4 in 4.2 in 3.0 in 27.0 oz 1110 YES 2015 1,199discont. check
Olympus E-M1 II (⇒ lft | rgt) 5.3 in 3.6 in 2.6 in 20.2 oz 440 YES 2016 1,999 latest check
Olympus PEN-F (⇒ lft | rgt) 4.9 in 2.8 in 1.5 in 15.1 oz 330 no 2016 1,199 latest check
Olympus E-M5 II (⇒ lft | rgt) 4.9 in 3.3 in 1.8 in 16.5 oz 310 YES 2015 1,099 latest check
Panasonic GH5 (⇒ lft | rgt) 5.5 in 3.9 in 3.4 in 25.6 oz 410 YES 2017 1,999 latest check
Panasonic G85 (⇒ lft | rgt) 5.0 in 3.5 in 2.9 in 17.8 oz 330 YES 2016 899 latest check
Panasonic ZS100 (⇒ lft | rgt) 4.4 in 2.6 in 1.7 in 11.0 oz 300 no 2016 699 latest check
Panasonic GX7 (⇒ lft | rgt) 4.8 in 2.8 in 2.2 in 14.2 oz 350 no 2013 999discont. check
Pentax K-3 (⇒ lft | rgt) 5.2 in 3.9 in 3.0 in 28.2 oz 560 YES 2013 1,299discont. check
Sony A6500 (⇒ lft | rgt) 4.7 in 2.6 in 2.1 in 16.0 oz 350 YES 2016 1,399 latest 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 somewhat cheaper (by 8 percent) than the GX8 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 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. 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Panasonic GX8 features a Four Thirds sensor and the Pentax K-3 II an APS-C sensor. The sensor area in the K-3 II is 63 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.5. The sensor in the GX8 has a native 4:3 aspect ratio, while the one in the K-3 II offers a 3:2 aspect.

Panasonic GX8 and Pentax K-3 II sensor measures
Sensor size

With 24.1MP, the K-3 II offers a higher resolution than the GX8 (20.2MP), but the K-3 II nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 3.34μm for the GX8) due to its larger sensor. It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation. Coming back 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.

GX8 versus K-3 II MP
Sensor resolution

For most 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 consideration, the K-3 II has a markedly higher DXO score than the GX8 (overall score 5 points higher), which will translate into better image quality. The advantage is based on 0.1 bits higher color depth, 1 EV in additional dynamic range, and 0.5 stops in additional low light sensitivity. The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

Sensor Characteristics
Camera Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Panasonic GX8 (⇒ rgt) Four Thirds 20.2 5184 3888 4K/30p 23.5 12.6 806 75
Pentax K-3 II (⇒ lft) APS-C 24.1 6016 4000 1080/60i 23.6 13.6 1106 80
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
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 GH5 (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/60p 23.9 13.0 807 77
Panasonic G85 (⇒ lft | rgt) Four Thirds 15.8 4592 3448 4K/30p 22.8 12.5 656 71
Panasonic ZS100 (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 22.8 12.5 559 70
Panasonic GX7 (⇒ lft | rgt) Four Thirds 15.8 4592 3448 1080/60p 22.6 12.2 718 70
Pentax K-3 (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i 23.7 13.4 1216 80
Sony A6500 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p 24.5 13.7 1405 85

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 GX8 provides a higher video resolution than the K-3 II. It can shoot video footage at 4K/30p, while the Pentax is limited to 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the GX8 has an electronic viewfinder (2360k 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 following table reports on some other key feature differences and similarities of the Panasonic GX8, the Pentax K-3 II, 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
Panasonic GX8 (⇒ rgt) 2360 no 3.0 1040 swivel YES 8000 10.0 no YES
Pentax K-3 II (⇒ lft) optical YES 3.2 1037 fixed no 8000 8.3 no YES
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
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 GH5 (⇒ lft | rgt) 3680 no 3.2 1620 swivel YES 8000 12.0 no YES
Panasonic G85 (⇒ lft | rgt) 2360 no 3.0 1040 swivel YES 4000 9.0 6.2 YES
Panasonic ZS100 (⇒ lft | rgt) 1166 no 3.0 1040 fixed YES 2000 10.0 YES YES
Panasonic GX7 (⇒ lft | rgt) 2760 no 3.0 1040 tilting YES 8000 5.0 7 YES
Pentax K-3 (⇒ lft | rgt) optical YES 3.2 1037 fixed no 8000 8.3 13 YES
Sony A6500 (⇒ lft | rgt) 2300 no 3.0 922 tilting YES 4000 11.0 6 YES

Both the GX8 and the K-3 II are current models that good online retailers will have in stock. You can check the latest prices, for example, at amazon. The K-3 II replaced the earlier Pentax K-3, while the GX8 followed on from the Panasonic GX7.

Summary

So what is the bottom line? Which of the two cameras – the Panasonic GX8 or the Pentax K-3 II – has the upper hand? Below is a summary of the relative strengths of each of the two contestants.


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Advantages of the Panasonic Lumix DMC-GX8:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
  • Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
  • Faster burst: Shoots at higher frequency (10 vs 8.3 flaps/sec) to capture the decisive moment.
  • More compact: Is smaller (133x78mm vs 131x100mm) and thus needs less room in the bag.
  • Less heavy: Is lighter (by 313g or 39 percent) and hence easier to carry around.
  • More legacy lens friendly: Can take a broad range of non-native lenses via adapters.

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Arguments in favor of the Pentax K-3 II:

  • More detail: Has more megapixels (24.1 vs 20.2MP), which boosts linear resolution by 11%.
  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • Better image quality: Scores markedly higher (5 points) in the DXO overall evaluation.
  • More dynamic range: Captures a broader range of light and dark details (1 EV of extra DR).
  • Better low-light sensitivity: Can shoot in dim conditions (0.5 stops ISO advantage).
  • 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.
  • Longer lasting: Gets more shots (720 versus 330) out of a single battery charge.

If the count of individual advantages (bullet points above) is taken as a guide, the match-up finishes in a tie (9 points each). 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.

GX8 09:09 K-3 II

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the GX8 or the K-3 II. 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 expert reviews are important. The adjacent table relays the overall verdicts of several of the most popular camera review sites. The full reviews are available, 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)
Panasonic GX8 (⇒ rgt) Rec 82/100 Silver 4.5/5 5/5 4.5/5 2015 1,199 latest check
Pentax K-3 II (⇒ lft) - - 5/5 4.5/5 5/5 2015 1,099 latest 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 1,199discont. 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 GH5 (⇒ lft | rgt) HiRec 85/100 Gold 4.5/5 5/5 5/5 2017 1,999 latest check
Panasonic G85 (⇒ lft | rgt) HiRec 84/100 Gold 5/5 4.5/5 4.5/5 2016 899 latest check
Panasonic ZS100 (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 4/5 4.5/5 2016 699 latest check
Panasonic GX7 (⇒ lft | rgt) Rec 79/100 Silver 5/5 4.5/5 5/5 2013 999discont. check
Pentax K-3 (⇒ lft | rgt) - 83/100 Gold 5/5 4.5/5 5/5 2013 1,299discont. check
Sony A6500 (⇒ lft | rgt) HiRec 85/100 Silver 4.5/5 5/5 4.5/5 2016 1,399 latest check

Care should be taken when interpreting the review scores above, though. The ratings are only valid when refering to cameras in the same category and of the same age. 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.

Other comparisons

In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored. If the camera you are interested in is not available, kindly get in touch, and I will try to add information on that model to the database.

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