Olympus E-M1 vs Pentax 645Z
The Olympus OM-D E-M1 and the Pentax 645Z are two digital cameras that were revealed to the public, respectively, in September 2013 and April 2014. The E-M1 is a mirrorless interchangeable lens camera, while the 645Z is a DSLR. The cameras are based on a Four Thirds (E-M1) and a medium format (645Z) sensor. The Olympus has a resolution of 15.9 megapixels, whereas the Pentax provides 51.1 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 and the Pentax 645Z? 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 and the Pentax 645Z. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All size dimensions are rounded to the nearest millimeter.
The E-M1 can be obtained in two different colors (black, silver), while the 645Z 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 645Z is considerably larger (49 percent) than the Olympus E-M1. Moreover, the 645Z is substantially heavier (212 percent) than the E-M1. 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.
The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.
|1.||Olympus E-M1||130 mm||94 mm||63 mm||497 g||350||Y||Sep 2013||1,399|
|2.||Pentax 645Z||156 mm||117 mm||123 mm||1550 g||650||Y||Apr 2014||8,499|
|3.||Canon 5DS||152 mm||116 mm||76 mm||930 g||700||Y||Feb 2015||3,699|
|4.||Canon 5DS R||152 mm||116 mm||76 mm||930 g||700||Y||Feb 2015||3,699|
|5.||Hasselblad X1D||150 mm||98 mm||71 mm||725 g||..||Y||Jun 2016||8,995|
|6.||Leica SL||147 mm||104 mm||39 mm||847 g||400||Y||Oct 2015||7,450|
|7.||Olympus E-M1 II||134 mm||91 mm||67 mm||574 g||440||Y||Sep 2016||1,999|
|8.||Olympus PEN-F||125 mm||72 mm||37 mm||427 g||330||n||Jan 2016||1,199|
|9.||Olympus E-M5 II||124 mm||85 mm||45 mm||469 g||310||Y||Feb 2015||1,099|
|10.||Olympus E-PL7||115 mm||67 mm||38 mm||357 g||350||n||Aug 2014||599|
|11.||Olympus E-P5||122 mm||69 mm||37 mm||420 g||330||n||May 2013||999|
|12.||Olympus E-M5||122 mm||89 mm||43 mm||425 g||360||Y||Feb 2012||1,299|
|13.||Olympus E-PL5||111 mm||64 mm||38 mm||325 g||360||n||Sep 2012||599|
|14.||Olympus E-PM2||110 mm||64 mm||34 mm||269 g||360||n||Sep 2012||499|
|15.||Panasonic GH4||133 mm||93 mm||84 mm||560 g||500||Y||Feb 2014||1,499|
|16.||Panasonic GH3||133 mm||93 mm||82 mm||550 g||540||Y||Sep 2012||1,299|
|17.||Pentax 645D||156 mm||117 mm||119 mm||1480 g||800||Y||Mar 2010||9,995|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will obviously take relative prices into account. The retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. The E-M1 was launched at a markedly lower price (by 84 percent) than the 645Z, 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 size of the imaging sensor is a crucial determinant 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 tend to lead to bigger and heavier cameras and lenses.
Of the two cameras under consideration, the Olympus E-M1 features a Four Thirds sensor and the Pentax 645Z a medium format sensor. The sensor area in the 645Z is 539 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 0.79. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.
With 51.1MP, the 645Z offers a higher resolution than the E-M1 (15.9MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 3.76μm for the E-M1) due to its larger sensor. Moreover, the 645Z is a somewhat more recent model (by 7 months) than the E-M1, and its sensor might have benefitted from technological advances during this time that further 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 645Z implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 645Z for good quality output (200 dots per inch) amounts to 41.3 x 31 inches or 104.9 x 78.6 cm, for very good quality (250 dpi) 33 x 24.8 inches or 83.9 x 62.9 cm, and for excellent quality (300 dpi) 27.5 x 20.6 inches or 69.9 x 52.4 cm. The corresponding values for the Olympus E-M1 are 23 x 17.3 inches or 58.5 x 43.9 cm for good quality, 18.4 x 13.8 inches or 46.8 x 35.1 cm for very good quality, and 15.4 x 11.5 inches or 39 x 29.3 cm for excellent quality prints.
The E-M1 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
The Olympus OM-D E-M1 has a native sensitivity range from ISO 200 to ISO 25600, which can be extended to ISO 100-25600. The corresponding ISO settings for the Pentax 645Z are ISO 100 to ISO 204800 (no boost).
Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 consideration, the 645Z offers substantially better image quality than the E-M1 (overall score 28 points higher). The advantage is based on 3 bits higher color depth, 2 EV in additional dynamic range, and 2.6 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.
| DXO |
|1.||Olympus E-M1||Four Thirds||15.9||4608||3456||1080/30p||23.0||12.7||757||73|
|2.||Pentax 645Z||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101|
|3.||Canon 5DS||Full Frame||50.3||8688||5792||1080/30p||24.7||12.4||2381||87|
|4.||Canon 5DS R||Full Frame||50.3||8688||5792||1080/30p||24.6||12.4||2308||86|
|5.||Hasselblad X1D||Medium Format||51.3||8272||6200||1080/25p||26.2||14.8||4489||102|
|6.||Leica SL||Full Frame||24.0||6000||4000||4K/30p||25.0||13.4||1821||88|
|7.||Olympus E-M1 II||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|8.||Olympus PEN-F||Four Thirds||20.2||5184||3888||1080/60p||23.1||12.4||894||74|
|9.||Olympus E-M5 II||Four Thirds||15.9||4608||3456||1080/60p||23.0||12.5||842||73|
|10.||Olympus E-PL7||Four Thirds||15.9||4608||3456||1080/30p||22.7||12.4||873||72|
|11.||Olympus E-P5||Four Thirds||15.9||4608||3456||1080/30p||22.8||12.4||895||72|
|12.||Olympus E-M5||Four Thirds||15.9||4608||3456||1080/60i||22.8||12.3||826||71|
|13.||Olympus E-PL5||Four Thirds||15.9||4608||3456||1080/30p||22.8||12.3||889||72|
|14.||Olympus E-PM2||Four Thirds||15.9||4608||3456||1080/30p||22.7||12.2||932||72|
|15.||Panasonic GH4||Four Thirds||15.9||4608||3456||4K/30p||23.2||12.8||791||74|
|16.||Panasonic GH3||Four Thirds||15.9||4608||3456||1080/60p||22.7||12.4||812||71|
|17.||Pentax 645D||Medium Format||39.5||7264||5440||none||24.6||12.6||1262||82|
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 645Z provides a faster frame rate than the E-M1. It can shoot movie footage at 1080/60i, while the Olympus is limited to 1080/30p.
Apart from 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 645Z 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 viewfinder in the E-M1 offers a wider field of view (100%) than the one in the 645Z (98%), so that a larger proportion of the captured image is visible in the finder. On the other hand, the viewfinder of the 645Z has a higher magnification (0.78x vs 0.74x), 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 and Pentax 645Z in connection with corresponding information for a sample of similar cameras.
|4.||Canon 5DS R||optical||Y||3.2||1040||fixed||n||1/8000s||5.0||n||n|
|7.||Olympus E-M1 II||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|9.||Olympus E-M5 II||2360||n||3.0||1037||swivel||Y||1/8000s||10.0||n||Y|
One feature that differentiates the E-M1 and the 645Z is in-body image stabilization (IBIS). The E-M1 reduces the risk of handshake-induced blur with all attached lenses, while the 645Z offers no blur reduction with lenses that themselves do not provide optical image stabilization.
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 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 and the Pentax 645Z 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 and the 645Z write their files to SDXC cards. The 645Z features dual card slots, which can be very useful in case a memory card fails. In contrast, the E-M1 only has one slot. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.
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 and Pentax 645Z and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|4.||Canon 5DS R||Y||mono||mono||Y||-||mini||3.0||-||-||-|
|7.||Olympus E-M1 II||Y||stereo||mono||Y||Y||micro||3.0||Y||-||-|
|9.||Olympus E-M5 II||Y||stereo||mono||Y||-||micro||2.0||Y||-||-|
It is notable that the E-M1 offers wifi support, while the 645Z 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.
The 645Z is a recent model that features in the current product line-up of Pentax. In contrast, the E-M1 has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the E-M1 was succeeded by the Olympus E-M1 II. 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? Is there a clear favorite between the Olympus E-M1 and the Pentax 645Z? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.
Reasons to prefer the Olympus OM-D E-M1:
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- More framing info: Has an electronic viewfinder that displays shooting data.
- More complete view: Has a viewfinder with a larger field of view (100% vs 98%).
- Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (10 vs 3 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- More compact: Is smaller (130x94mm vs 156x117mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 1053g or 68 percent) and hence easier to carry around.
- Sharper images: Has hand-shake reducing image stabilization built-in.
- 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.
- More affordable: Was introduced into a lower priced category (84 percent cheaper at launch).
- More heavily discounted: Has been on the market for longer (launched in September 2013).
Advantages of the Pentax 645Z:
- More detail: Has more megapixels (51.1 vs 15.9MP), which boosts linear resolution by 79%.
- Better image quality: Scores substantially higher (28 points) in the DXO overall evaluation.
- Richer colors: Generates noticeably more natural colors (3 bits more color depth).
- More dynamic range: Captures a broader range of light and dark details (2 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (2.6 stops ISO advantage).
- Better video: Provides higher movie framerates (1080/60i versus 1080/30p).
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.74x).
- 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 (650 versus 350) out of a single battery charge.
- Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- More modern: Was introduced somewhat (7 months) more recently.
If the count of relative strengths (bullet points above) is taken as a measure, the match-up finishes in a tie (14 points each). 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 wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports 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 and the Pentax 645Z 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 remains incomplete and does no justice, for example, to the way the E-M1 or the 645Z 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 why hands-on reviews by experts are important. The following table reports the overall ratings of the cameras as published by some of the major 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||5/5||+ +||84/100||4.5/5||4.5/5||Sep 2013||1,399|
|2.||Pentax 645Z||5/5||..||..||4.5/5||5/5||Apr 2014||8,499|
|3.||Canon 5DS||..||+||83/100||4.5/5||4.5/5||Feb 2015||3,699|
|4.||Canon 5DS R||5/5||+||83/100||5/5||4.5/5||Feb 2015||3,699|
|5.||Hasselblad X1D||..||o||81/100||..||4/5||Jun 2016||8,995|
|6.||Leica SL||4/5||..||84/100||4.5/5||4/5||Oct 2015||7,450|
|7.||Olympus E-M1 II||5/5||+ +||85/100||4.5/5||4.5/5||Sep 2016||1,999|
|8.||Olympus PEN-F||..||..||82/100||4.5/5||5/5||Jan 2016||1,199|
|9.||Olympus E-M5 II||5/5||+ +||81/100||5/5||5/5||Feb 2015||1,099|
|10.||Olympus E-PL7||4/5||+||..||5/5||4/5||Aug 2014||599|
|11.||Olympus E-P5||5/5||+ +||78/100||4.5/5||5/5||May 2013||999|
|12.||Olympus E-M5||4/5||+ +||80/100||4.5/5||5/5||Feb 2012||1,299|
|13.||Olympus E-PL5||3/5||+ +||..||4.5/5||4.5/5||Sep 2012||599|
|14.||Olympus E-PM2||3/5||..||77/100||5/5||4.5/5||Sep 2012||499|
|15.||Panasonic GH4||5/5||+ +||85/100||5/5||5/5||Feb 2014||1,499|
|16.||Panasonic GH3||5/5||+ +||79/100||4.5/5||4.5/5||Sep 2012||1,299|
|17.||Pentax 645D||5/5||..||..||..||..||Mar 2010||9,995|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
Care should be taken when interpreting the review scores above, though. The assessments were made in relation to similar cameras of the same technological generation. Hence, a score should always be seen in the context of the camera's market launch date and its price, 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? In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.
Specifications: Olympus E-M1 vs Pentax 645Z
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||Pentax 645Z|
|Camera Type||Mirrorless system camera||Digital single lens reflex|
|Camera Lens||Micro Four Thirds lenses||Pentax 645 mount lenses|
|Launch Date||September 2013||April 2014|
|Launch Price||USD 1,399||USD 8,499|
|Sensor Specs||Olympus E-M1||Pentax 645Z|
|Sensor Format||Four Thirds Sensor||Medium Format Sensor|
|Sensor Size||17.3 x 13.0 mm||43.8 x 32.8 mm|
|Sensor Area||224.9 mm2||1436.64 mm2|
|Sensor Diagonal||21.6 mm||54.7 mm|
|Sensor Resolution||15.9 Megapixels||51.1 Megapixels|
|Image Resolution||4608 x 3456 pixels||8256 x 6192 pixels|
|Pixel Pitch||3.76 μm||5.30 μm|
|Pixel Density||7.08 MP/cm2||3.56 MP/cm2|
|Moiré control||no AA filter||no AA filter|
|Movie Capability||1080/30p Video||1080/60i Video|
|ISO Setting||200 - 25,600 ISO||100 - 204,800 ISO|
|ISO Boost||100 - 25,600 ISO||no Enhancement|
|Image Processor||TruePIC VII||PRIME III|
|DXO Sensor Quality (score)||73||101|
|DXO Color Depth (bits)||23.0||26.0|
|DXO Dynamic Range (EV)||12.7||14.7|
|DXO Low Light (ISO)||757||4505|
|Screen Specs||Olympus E-M1||Pentax 645Z|
|Viewfinder Type||Electronic viewfinder||Optical viewfinder|
|Viewfinder Field of View||100%||98%|
|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||Tilting screen||Tilting screen|
|Touch Input||Touchscreen||no Touchscreen|
|Shooting Specs||Olympus E-M1||Pentax 645Z|
|Focus System||On-Sensor Phase-detect||Phase-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/4000s|
|Continuous Shooting||10 shutter flaps/s||3 shutter flaps/s|
|Shutter Life Expectancy||150 000 actuations||100 000 actuations|
|Electronic Shutter||YES||no E-Shutter|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|Image Stabilization||In-body stabilization||Lens stabilization only|
|Fill Flash||no On-Board Flash||no On-Board Flash|
|Storage Medium||SDXC cards||SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||UHS-I||UHS-I|
|Connectivity Specs||Olympus E-M1||Pentax 645Z|
|Studio Flash||PC Sync socket||PC Sync socket|
|USB Connector||USB 2.0||USB 3.0|
|HDMI Port||micro HDMI||mini HDMI|
|Microphone Port||External MIC port||External MIC port|
|Wifi Support||Wifi built-in||no Wifi|
|Body Specs||Olympus E-M1||Pentax 645Z|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||350 shots per charge||650 shots per charge|
130 x 94 x 63 mm
(5.1 x 3.7 x 2.5 in)
156 x 117 x 123 mm
(6.1 x 4.6 x 4.8 in)
|Camera Weight||497 g (17.5 oz)||1550 g (54.7 oz)|
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