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Pentax K-3 versus Olympus E-M1

The Pentax K-3 and the Olympus OM-D E-M1 are two enthusiast cameras that were officially introduced, respectively, in October 2013 and September 2013. The K-3 is a DSLR, while the E-M1 is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (K-3) and a Four Thirds sensor. The Pentax has a resolution of 24.1 megapixel, whereas the Olympus provides 15.9 MP.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Pentax K-3 and the Olympus E-M1. Three consecutive perspectives from the front, the top, and the back are presented. 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 – the K-3 – represents the basis or 100 percent across all the size and weight measures).

Pentax K-3 vs Olympus E-M1 front
K-3 versus E-M1 top view
K-3 and E-M1 rear side
Body view (K-3 on the left)

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Olympus E-M1 is somewhat smaller (7 percent) than the Pentax K-3. Moreover, the E-M1 is substantially lighter (38 percent) than the K-3. Cameras intended for semi-professional or professional use tend to be a bit bulkier in order to give them the necessary ruggedness. 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)
Pentax K-3 (⇒ rgt) 5.2 in 3.9 in 3.0 in 28.2 oz 560 YES 2013 1,299discont. check
Olympus E-M1 (⇒ lft) 5.1 in 3.7 in 2.5 in 17.5 oz 350 YES 2013 1,399discont. check
Canon 70D (⇒ lft | rgt) 5.5 in 4.1 in 3.1 in 26.6 oz 920 YES 2013 1,199discont. check
Nikon D7100 (⇒ lft | rgt) 5.4 in 4.2 in 3.0 in 27.0 oz 950 YES 2013 1,199discont. 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
Olympus E-M10 (⇒ lft | rgt) 4.7 in 3.2 in 1.8 in 14.0 oz 320 no 2014 699discont. check
Olympus E-P5 (⇒ lft | rgt) 4.8 in 2.7 in 1.5 in 14.8 oz 330 no 2013 999discont. check
Olympus E-M5 (⇒ lft | rgt) 4.8 in 3.5 in 1.7 in 15.0 oz .. YES 2012 1,299discont. check
Panasonic GX8 (⇒ lft | rgt) 5.2 in 3.1 in 2.5 in 17.2 oz 330 YES 2015 1,199 latest check
Panasonic GH4 (⇒ lft | rgt) 5.2 in 3.7 in 3.3 in 19.8 oz 500 YES 2014 1,499discont. check
Pentax K-3 II (⇒ lft | rgt) 5.2 in 3.9 in 3.0 in 28.2 oz 720 YES 2015 1,099 latest check
Sony A6500 (⇒ lft | rgt) 4.7 in 2.6 in 2.1 in 16.0 oz 350 YES 2016 1,399 latest check
Sony A7 II (⇒ lft | rgt) 5.0 in 3.8 in 2.4 in 21.1 oz 350 YES 2014 1,999 latest check
Sony A77 II (⇒ lft | rgt) 5.6 in 4.1 in 3.2 in 22.8 oz 480 YES 2014 1,199 latest check
Sony RX10 (⇒ lft | rgt) 5.1 in 3.5 in 4.0 in 28.7 oz 420 YES 2013 1,299discont. check

The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The K-3 was somewhat cheaper (by 7 percent) than the E-M1 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. 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 are more costly to manufacture and tent to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Pentax K-3 features an APS-C sensor and the Olympus E-M1 a Four Thirds sensor. The sensor area in the E-M1 is 39 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 2.0. The sensor in the K-3 has a native 3:2 aspect ratio, while the one in the E-M1 offers a 4:3 aspect.

Pentax K-3 and Olympus E-M1 sensor measures
Sensor size

With 24.1MP, the K-3 offers a higher resolution than the E-M1 (15.9MP), but the K-3 nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 3.75μm for the E-M1) 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 to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

K-3 versus E-M1 MP
Sensor resolution

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 K-3 has a notably higher overall DXO score than the K-3 (overall score 7 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.7 bits higher color depth, 0.7 EV in additional dynamic range, and 0.7 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
Pentax K-3 (⇒ rgt) APS-C 24.1 6016 4000 1080/60i 23.7 13.4 1216 80
Olympus E-M1 (⇒ lft) Four Thirds 15.9 4608 3456 1080/30p 23.0 12.7 757 73
Canon 70D (⇒ lft | rgt) APS-C 20.0 5472 3648 1080/30p 22.5 11.6 926 68
Nikon D7100 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24.2 13.7 1256 83
Olympus E-M5 II (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/60p 23.0 12.5 842 73
Olympus E-M10 (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/30p 22.8 12.3 884 72
Olympus E-P5 (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/30p 22.8 12.4 895 72
Olympus E-M5 (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/60i 22.8 12.3 826 71
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 K-3 II (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i 23.6 13.6 1106 80
Sony A6500 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p 24.5 13.7 1405 85
Sony A7 II (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.9 13.6 2449 90
Sony A77 II (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p - - - -
Sony RX10 (⇒ lft | rgt) 1-inch 20.0 5472 3648 1080/60p 22.9 12.6 474 69

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 K-3 provides a higher frame rate than the E-M1. It can shoot video footage at 1080/60i, while the Olympus is limited to 1080/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the E-M1 has an electronic viewfinder (2360k 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 table below summarizes some of the other core capabilities of the Pentax K-3 and Olympus E-M1 in connection with corresponding information for a sample of similar cameras. 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
Pentax K-3 (⇒ rgt) optical YES 3.2 1037 fixed no 8000 8.3 13 YES
Olympus E-M1 (⇒ lft) 2360 no 3.0 1037 tilting YES 8000 10.0 no YES
Canon 70D (⇒ lft | rgt) optical YES 3.0 1040 swivel YES 8000 7.0 12 no
Nikon D7100 (⇒ lft | rgt) optical YES 3.2 1229 fixed no 8000 6.0 12 no
Olympus E-M5 II (⇒ lft | rgt) 2360 no 3.0 1037 swivel YES 8000 10.0 no YES
Olympus E-M10 (⇒ lft | rgt) 1440 no 3.0 1037 tilting YES 4000 8.0 5.8 YES
Olympus E-P5 (⇒ lft | rgt) no no 3.0 1037 tilting YES 8000 9.0 7 YES
Olympus E-M5 (⇒ lft | rgt) 1440 no 3.0 610 tilting YES 4000 9.0 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 K-3 II (⇒ lft | rgt) optical YES 3.2 1037 fixed no 8000 8.3 no YES
Sony A6500 (⇒ lft | rgt) 2300 no 3.0 922 tilting YES 4000 11.0 6 YES
Sony A7 II (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no YES
Sony A77 II (⇒ lft | rgt) 2359 YES 3.0 1229 full-flex no 8000 12.0 12 YES
Sony RX10 (⇒ lft | rgt) 1440 YES 3.0 1229 tilting no 3200 10.0 10.2 no

Both the K-3 and the E-M1 have been discontinued, but can regularly be found used on ebay. The E-M1 was replaced by the Olympus E-M1 II, while the K-3 was followed by the Pentax K-3 II.

Summary

So what conclusions can be drawn? Is the Pentax K-3 better than the Olympus E-M1 or vice versa? Below is a summary of the relative strengths of each of the two contestants.


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Reasons to prefer the Pentax K-3:

  • More detail: Offers more megapixels (24.1 vs 15.9MP) with a 25% higher linear resolution.
  • Better image quality: Scores markedly higher (7 points) in the DXO overall assessment.
  • More dynamic range: Captures a larger spectrum of light and dark details (0.7 EV of extra DR).
  • Better low-light sensitivity: Requires less light for good images (0.7 stops ISO advantage).
  • Better video: Provides higher movie framerates (1080/60i vs 1080/30p).
  • 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.
  • Longer lasting: Can take more shots (560 versus 350) on a single battery charge.
  • Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.

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Arguments in favor of the Olympus OM-D E-M1:

  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
  • Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
  • Less heavy: Has a lower weight (by 303g or 38 percent) and is thus easier to take along.
  • More legacy lens friendly: Can use many non-native lenses via adapters.

If the count of relative strengths (bullet points above) is taken as a measure, the K-3 is the clear winner of the match-up (10 : 5 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features.

K-3 10:05 E-M1

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it remains incomplete and does no justice, for example, to the way the K-3 or the E-M1 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 where reviews by experts come in. The following table reports the overall rankings of the cameras as published by some of the major 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)
Pentax K-3 (⇒ rgt) - 83/100 Gold 5/5 4.5/5 5/5 2013 1,299discont. check
Olympus E-M1 (⇒ lft) HiRec 84/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,399discont. check
Canon 70D (⇒ lft | rgt) HiRec 83/100 Gold 4.5/5 4.5/5 5/5 2013 1,199discont. check
Nikon D7100 (⇒ lft | rgt) HiRec 85/100 Gold 4.5/5 5/5 4.5/5 2013 1,199discont. check
Olympus E-M5 II (⇒ lft | rgt) HiRec 81/100 Silver 5/5 4.5/5 5/5 2015 1,099 latest check
Olympus E-M10 (⇒ lft | rgt) - 80/100 Gold 5/5 4.5/5 5/5 2014 699discont. check
Olympus E-P5 (⇒ lft | rgt) HiRec 78/100 Silver 4.5/5 4.5/5 5/5 2013 999discont. check
Olympus E-M5 (⇒ lft | rgt) HiRec 80/100 Gold 4.5/5 5/5 5/5 2012 1,299discont. 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 1,499discont. check
Pentax K-3 II (⇒ lft | rgt) - - 5/5 4.5/5 5/5 2015 1,099 latest check
Sony A6500 (⇒ lft | rgt) HiRec 85/100 Silver 4.5/5 5/5 4.5/5 2016 1,399 latest check
Sony A7 II (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 5/5 2014 1,999 latest check
Sony A77 II (⇒ lft | rgt) - 80/100 Silver 4.5/5 4/5 5/5 2014 1,199 latest check
Sony RX10 (⇒ lft | rgt) Rec 80/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,299discont. check

Care should be taken when interpreting the review scores above, 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 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

If you would like to see a different side-by-side camera review, just use the search menu 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, please send me an email, and I will try to locate and add the respective data to the application.

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