Olympus E-M1 III vs Pentax K-3 II
The Olympus OM-D E-M1 Mark III and the Pentax K-3 II are two enthusiast cameras that were revealed to the public, respectively, in February 2020 and April 2015. The E-M1 III is a mirrorless interchangeable lens camera, while the K-3 II is a DSLR. The cameras are based on a Four Thirds (E-M1 III) and an APS-C (K-3 II) sensor. The Olympus has a resolution of 20.2 megapixels, whereas the Pentax provides 24.1 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus OM-D E-M1 Mark III and the Pentax K-3 II? Which one should you buy? Read on to find out how these two cameras compare with respect to their body size, their imaging sensors, their shooting features, their input-output connections, and their reception by expert reviewers.
The side-by-side display below illustrates the physical size and weight of the Olympus E-M1 III and the Pentax K-3 II. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side are shown. All width, height and depth measures are rounded to the nearest millimeter.
The K-3 II can be obtained in two different colors (black, silver), while the E-M1 III is only available in black.
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 Olympus E-M1 III. Moreover, the K-3 II is substantially heavier (38 percent) than the E-M1 III. 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 and compare 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 E-M1 III gets 420 shots out of its BLH-1 battery, while the K-3 II can take 720 images on a single charge of its D-LI90 power pack. The power pack in the E-M1 III can be charged via the USB port, so that it is not always necessary to take the battery charger along when travelling.
The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.
|1.||Olympus E-M1 III||134 mm||91 mm||69 mm||580 g||420||Y||Feb 2020||1,799|
|2.||Pentax K-3 II||131 mm||100 mm||77 mm||800 g||720||Y||Apr 2015||1,099|
|3.||Fujifilm X-H1||140 mm||97 mm||86 mm||673 g||310||Y||Feb 2018||1,899|
|4.||Nikon Z6 II||134 mm||101 mm||70 mm||705 g||410||Y||Oct 2020||1,999|
|5.||Olympus E-M5 III||125 mm||85 mm||50 mm||414 g||310||Y||Oct 2019||1,199|
|6.||Olympus E-M1X||144 mm||147 mm||75 mm||997 g||870||Y||Jan 2019||2,999|
|7.||Olympus E-M1 II||134 mm||91 mm||67 mm||574 g||440||Y||Sep 2016||1,999|
|8.||Panasonic G90||130 mm||94 mm||77 mm||536 g||290||Y||Apr 2019||999|
|9.||Panasonic G9||137 mm||97 mm||92 mm||658 g||400||Y||Nov 2017||1,699|
|10.||Panasonic GH5||139 mm||98 mm||87 mm||725 g||410||Y||Jan 2017||1,999|
|11.||Pentax K-3 III||135 mm||104 mm||74 mm||820 g||800||Y||Mar 2021||1,999|
|12.||Pentax KP||132 mm||101 mm||76 mm||703 g||390||Y||Jan 2017||1,099|
|13.||Pentax K-70||126 mm||93 mm||74 mm||688 g||410||Y||Jun 2016||649|
|14.||Pentax K-3||131 mm||100 mm||77 mm||800 g||560||Y||Oct 2013||1,299|
|15.||Pentax K-5||131 mm||97 mm||73 mm||760 g||740||Y||Sep 2010||1,099|
|16.||Sony A7C||124 mm||71 mm||60 mm||509 g||740||Y||Sep 2020||1,799|
|17.||Sony A7 III||127 mm||96 mm||74 mm||650 g||610||Y||Feb 2018||1,999|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
The price is, of course, an important factor in any camera decision. 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 39 percent) than the E-M1 III, 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.
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. 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 tend to lead to bigger and heavier cameras and lenses.
Of the two cameras under consideration, the Olympus E-M1 III 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 E-M1 III has a native 4:3 aspect ratio, while the one in the K-3 II offers a 3:2 aspect.
With 24.1MP, the K-3 II offers a higher resolution than the E-M1 III (20.2MP), but the K-3 II nevertheless has larger individual pixels (pixel pitch of 3.90μm versus 3.34μm for the E-M1 III) due to its larger sensor. However, the E-M1 III is a much more recent model (by 4 years and 9 months) than the K-3 II, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units. 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.
The resolution advantage of the Pentax K-3 II implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-3 II for good quality output (200 dots per inch) amounts to 30.1 x 20 inches or 76.4 x 50.8 cm, for very good quality (250 dpi) 24.1 x 16 inches or 61.1 x 40.6 cm, and for excellent quality (300 dpi) 20.1 x 13.3 inches or 50.9 x 33.9 cm. The corresponding values for the Olympus E-M1 III are 25.9 x 19.4 inches or 65.8 x 49.4 cm for good quality, 20.7 x 15.6 inches or 52.7 x 39.5 cm for very good quality, and 17.3 x 13 inches or 43.9 x 32.9 cm for excellent quality prints.
The E-M1 III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
Both cameras have the capacity to capture high quality composite images by combining multiple shots after shifting the sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).
The Olympus OM-D E-M1 Mark III has a native sensitivity range from ISO 200 to ISO 25600, which can be extended to ISO 64-25600. The corresponding ISO settings for the Pentax K-3 II are ISO 100 to ISO 51200 (no boost).
Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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"). The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.
| DXO |
|1.||Olympus E-M1 III||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|2.||Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
|4.||Nikon Z6 II||Full Frame||24.3||6048||4024||4K/60p||..||..||..||..|
|5.||Olympus E-M5 III||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|6.||Olympus E-M1X||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|7.||Olympus E-M1 II||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|8.||Panasonic G90||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|9.||Panasonic G9||Four Thirds||20.2||5184||3888||4K/60p||..||..||..||..|
|10.||Panasonic GH5||Four Thirds||20.2||5184||3888||4K/60p||23.9||13.0||807||77|
|11.||Pentax K-3 III||APS-C||25.6||6192||4128||4K/30p||..||..||..||..|
|16.||Sony A7C||Full Frame||24.0||6000||4000||4K/30p||25.0||14.7||3407||95|
|17.||Sony A7 III||Full Frame||24.0||6000||4000||4K/30p||25.0||14.7||3730||96|
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 E-M1 III 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.
Apart from body and sensor, cameras can and do differ across a range of features. For example, the E-M1 III 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 viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the E-M1 III has a higher magnification than the one of the K-3 II (0.74x vs 0.63x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Olympus E-M1 III and Pentax K-3 II in connection with corresponding information for a sample of similar cameras.
|1.||Olympus E-M1 III||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|2.||Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y|
|4.||Nikon Z6 II||3690||Y||3.2||2100||tilting||Y||1/8000s||14.0||n||Y|
|5.||Olympus E-M5 III||2360||n||3.0||1040||swivel||Y||1/8000s||10.0||n||Y|
|7.||Olympus E-M1 II||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|11.||Pentax K-3 III||optical||Y||3.2||1620||fixed||Y||1/8000s||12.0||n||Y|
|17.||Sony A7 III||2359||n||3.0||922||tilting||Y||1/8000s||10.0||n||Y|
One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The E-M1 III has a touchscreen, while the K-3 II has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.The E-M1 III has an articulated LCD that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in snapping selfies. In contrast, the K-3 II does not have a selfie-screen.
The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the E-M1 III is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).
The Olympus E-M1 III and the Pentax K-3 II both have an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.
Concerning the storage of imaging data, both the E-M1 III and the K-3 II write their files to SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. The E-M1 III supports UHS-II cards (on its first slot), while the K-3 II can use UHS-I cards.
For some imaging applications, the extent to which a camera can communicate with its environment can be an important aspect in the camera decision process. The table below provides an overview of the connectivity of the Olympus OM-D E-M1 Mark III and Pentax K-3 II and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|1.||Olympus E-M1 III||Y||stereo||mono||Y||Y||micro||3.1||Y||-||Y|
|2.||Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
|4.||Nikon Z6 II||Y||stereo||mono||Y||Y||micro||3.2||Y||-||Y|
|5.||Olympus E-M5 III||Y||stereo||mono||Y||-||micro||2.0||Y||-||Y|
|7.||Olympus E-M1 II||Y||stereo||mono||Y||Y||micro||3.0||Y||-||-|
|11.||Pentax K-3 III||Y||stereo||mono||Y||Y||micro||3.2||Y||-||Y|
|17.||Sony A7 III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
It is notable that the E-M1 III offers wifi support, while the K-3 II does not. Wifi can be a very convenient means to transfer image data to an off-camera location.
Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.
Travel and landscape photographers will find it useful that the K-3 II has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.
The E-M1 III is a recent model that features in the current product line-up of Olympus. In contrast, the K-3 II has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the K-3 II was succeeded by the Pentax K-3 III. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Olympus and Pentax websites.
So what is the bottom line? Which of the two cameras – the Olympus E-M1 III or the Pentax K-3 II – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.
Advantages of the Olympus OM-D E-M1 Mark III:
- Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- More framing info: Has an electronic viewfinder that displays shooting data.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.74x vs 0.63x).
- 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.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster burst: Shoots at higher frequency (18 vs 8.3 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- Less heavy: Is lighter (by 220g or 27 percent) and hence easier to carry around.
- Easier travel charging: Can be conveniently charged via its USB port.
- More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
- Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
- Easier wireless transfer: Supports Bluetooth for image sharing without cables.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- More modern: Reflects 4 years and 9 months of technical progress since the K-3 II launch.
Reasons to prefer the Pentax K-3 II:
- More detail: Has more megapixels (24.1 vs 20.2MP), which boosts linear resolution by 11%.
- 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.
- Longer lasting: Gets more shots (720 versus 420) out of a single battery charge.
- Easier geotagging: Features an internal GPS sensor to log localization data.
- More affordable: Was introduced into a lower priced category (39 percent cheaper at launch).
- More heavily discounted: Has been around for much longer (launched in April 2015).
If the number of relative strengths (bullet points above) is taken as a guide, the E-M1 III is the clear winner of the match-up (16 : 8 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 before making a decision on a new camera. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro shooter. Hence, the decision which camera is best and worth buying is often a very personal one.
How about other alternatives? Do the specifications of the Olympus E-M1 III and the Pentax K-3 II place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best DSLR Camera listings whether the two cameras rank among the cream of the crop.
In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it says little about, for example, the shooting experience and imaging performance of the E-M1 III and the K-3 II in practical situations. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable.
This is where reviews by experts come in. The adjacent summary-table relays the overall verdicts of several of the most popular camera review sites (amateurphotographer [AP], cameralabs [CL], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.
|1.||Olympus E-M1 III||5/5||..||83/100||4.5/5||4/5||Feb 2020||1,799|
|2.||Pentax K-3 II||4.5/5||..||..||5/5||5/5||Apr 2015||1,099|
|3.||Fujifilm X-H1||..||+||86/100||4.5/5||4.5/5||Feb 2018||1,899|
|4.||Nikon Z6 II||4.5/5||..||89/100||4.5/5||4.5/5||Oct 2020||1,999|
|5.||Olympus E-M5 III||5/5||+||82/100||4.5/5||4.5/5||Oct 2019||1,199|
|6.||Olympus E-M1X||4.5/5||o||..||4.5/5||..||Jan 2019||2,999|
|7.||Olympus E-M1 II||5/5||+ +||85/100||4.5/5||4.5/5||Sep 2016||1,999|
|8.||Panasonic G90||4.5/5||+||83/100||4.5/5||4.5/5||Apr 2019||999|
|9.||Panasonic G9||..||+ +||85/100||5/5||5/5||Nov 2017||1,699|
|10.||Panasonic GH5||4.5/5||+ +||85/100||4.5/5||5/5||Jan 2017||1,999|
|11.||Pentax K-3 III||..||..||..||..||..||Mar 2021||1,999|
|12.||Pentax KP||4/5||..||82/100||5/5||4.5/5||Jan 2017||1,099|
|13.||Pentax K-70||4.5/5||..||79/100||4.5/5||4.5/5||Jun 2016||649|
|14.||Pentax K-3||4/5||..||83/100||5/5||5/5||Oct 2013||1,299|
|15.||Pentax K-5||4/5||..||83/100||5/5||4.5/5||Sep 2010||1,099|
|16.||Sony A7C||3.5/5||..||86/100||4/5||4/5||Sep 2020||1,799|
|17.||Sony A7 III||..||+ +||89/100||5/5||5/5||Feb 2018||1,999|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The above review scores should be interpreted with care, though. The ratings are only valid when referring 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 comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.
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 use the search menu below. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.
Specifications: Olympus E-M1 III vs Pentax K-3 II
Below is a side-by-side comparison of the specs of the two cameras to facilitate a quick review of their differences and common features.
|Camera Model||Olympus E-M1 III||Pentax K-3 II|
|Camera Type||Mirrorless system camera||Digital single lens reflex|
|Camera Lens||Micro Four Thirds lenses||Pentax K mount lenses|
|Launch Date||February 2020||April 2015|
|Launch Price||USD 1,799||USD 1,099|
|Sensor Specs||Olympus E-M1 III||Pentax K-3 II|
|Sensor Format||Four Thirds Sensor||APS-C Sensor|
|Sensor Size||17.3 x 13.0 mm||23.5 x 15.6 mm|
|Sensor Area||224.9 mm2||366.6 mm2|
|Sensor Diagonal||21.6 mm||28.2 mm|
|Sensor Resolution||20.2 Megapixels||24.1 Megapixels|
|Image Resolution||5184 x 3888 pixels||6016 x 4000 pixels|
|Pixel Pitch||3.34 μm||3.90 μm|
|Pixel Density||8.96 MP/cm2||6.56 MP/cm2|
|Moiré control||no AA filter||no AA filter|
|Movie Capability||4K/30p Video||1080/60i Video|
|ISO Setting||200 - 25,600 ISO||100 - 51,200 ISO|
|ISO Boost||64 - 25,600 ISO||no Enhancement|
|Image Processor||TruePic IX||PRIME III|
|DXO Sensor Quality (score)||..||80|
|DXO Color Depth (bits)||..||23.6|
|DXO Dynamic Range (EV)||..||13.6|
|DXO Low Light (ISO)||..||1106|
|Screen Specs||Olympus E-M1 III||Pentax K-3 II|
|Viewfinder Type||Electronic viewfinder||Optical viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2360k dots|
|Top-Level Screen||no Top Display||Control Panel|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.2inch|
|LCD Resolution||1037k dots||1037k dots|
|LCD Attachment||Swivel screen||Fixed screen|
|Touch Input||Touchscreen||no Touchscreen|
|Shooting Specs||Olympus E-M1 III||Pentax K-3 II|
|Focus System||On-Sensor Phase-detect||Phase-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/8000s|
|Continuous Shooting||18 shutter flaps/s||8.3 shutter flaps/s|
|Shutter Life Expectancy||400 000 actuations||200 000 actuations|
|Electronic Shutter||up to 1/32000s||no E-Shutter|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||no On-Board Flash||no On-Board Flash|
|Storage Medium||SDXC cards||SDXC cards|
|Second Storage Option||Dual card slots||Dual card slots|
|UHS card support||Single UHS-II||UHS-I|
|Connectivity Specs||Olympus E-M1 III||Pentax K-3 II|
|Studio Flash||PC Sync socket||PC Sync socket|
|USB Connector||USB 3.1||USB 3.0|
|HDMI Port||micro HDMI||mini HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||Headphone port||Headphone port|
|Wifi Support||Wifi built-in||no Wifi|
|Bluetooth Support||Bluetooth built-in||no Bluetooth|
|Geotagging||no internal GPS||GPS built-in|
|Body Specs||Olympus E-M1 III||Pentax K-3 II|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||420 shots per charge||720 shots per charge|
|In-Camera Charging||USB charging||no USB charging|
134 x 91 x 69 mm
(5.3 x 3.6 x 2.7 in)
131 x 100 x 77 mm
(5.2 x 3.9 x 3.0 in)
|Camera Weight||580 g (20.5 oz)||800 g (28.2 oz)|
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