Olympus E-PM1 vs OM System OM-1
The Olympus PEN E-PM1 and the OM System OM-1 are two digital cameras that were announced, respectively, in June 2011 and February 2022. Both the E-PM1 and the OM-1 are mirrorless interchangeable lens cameras that are equipped with a Four Thirds sensor. The Olympus has a resolution of 12.2 megapixels, whereas the OM System provides 20.2 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.

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Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus PEN E-PM1 and the OM System OM-1? 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.
Body comparison
An illustration of the physical size and weight of the Olympus E-PM1 and the OM System OM-1 is provided in the side-by-side display below. The two cameras are presented according to their relative size. 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.
The E-PM1 can be obtained in six different colors (black, silver, brown, pink, purple, white), while the OM-1 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 OM System OM-1 is considerably larger (76 percent) than the Olympus E-PM1. Moreover, the OM-1 is substantially heavier (126 percent) than the E-PM1. It is noteworthy in this context that the OM-1 is splash and dust-proof, while the E-PM1 does not feature any corresponding weather-sealing.
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. In this particular case, both cameras feature the same lens mount, so that they can use the same lenses. You can compare the optics available in the Micro Four Thirds Lens Catalog. Mirrorless cameras, such as the two under consideration, have the additional advantage of having a short flange to focal plane distance, which makes it possible to mount many lenses from other systems onto the camera via adapters.
Concerning battery life, the E-PM1 gets 330 shots out of its Olympus BLS-5 battery, while the OM-1 can take 520 images on a single charge of its OM System BLX-1 power pack. The power pack in the OM-1 can be charged via the USB port, which can be very convenient when travelling.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.

| Camera Model |
Camera Width |
Camera Height |
Camera Depth |
Camera Weight |
Battery Life |
Weather Sealing |
Camera Launch |
Launch Price |
Street Price |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Olympus E-PM1 | 110 mm | 64 mm | 34 mm | 265 g | 330 | n | Jun 2011 | US$ 499 | ebay.com | |
| 2. | OM System OM-1 | 135 mm | 92 mm | 73 mm | 599 g | 520 | Y | Feb 2022 | US$ 2 199 | ebay.com | |
| 3. | Olympus E-M1 II | 134 mm | 91 mm | 67 mm | 574 g | 440 | Y | Sep 2016 | US$ 1 999 | ebay.com | |
| 4. | Olympus E-M1 III | 134 mm | 91 mm | 69 mm | 580 g | 420 | Y | Feb 2020 | US$ 1 799 | ebay.com | |
| 5. | Olympus E-P3 | 122 mm | 69 mm | 34 mm | 369 g | 330 | n | Jun 2011 | US$ 799 | ebay.com | |
| 6. | Olympus E-PL1 | 115 mm | 72 mm | 42 mm | 334 g | 290 | n | Feb 2010 | US$ 599 | ebay.com | |
| 7. | Olympus E-PL2 | 114 mm | 72 mm | 42 mm | 362 g | 280 | n | Jan 2011 | US$ 599 | ebay.com | |
| 8. | Olympus E-PL3 | 110 mm | 64 mm | 37 mm | 313 g | 300 | n | Jun 2011 | US$ 599 | ebay.com | |
| 9. | Olympus E-PL5 | 111 mm | 64 mm | 38 mm | 325 g | 360 | n | Sep 2012 | US$ 599 | ebay.com | |
| 10. | Olympus E-PM2 | 110 mm | 64 mm | 34 mm | 269 g | 360 | n | Sep 2012 | US$ 499 | ebay.com | |
| 11. | OM System OM-1 II | 135 mm | 92 mm | 73 mm | 599 g | 500 | Y | Jan 2024 | US$ 2 399 | amazon.com | |
| 12. | OM System OM-3 | 139 mm | 89 mm | 46 mm | 496 g | 590 | Y | Feb 2025 | US$ 1 999 | amazon.com | |
| 13. | Panasonic G2 | 124 mm | 84 mm | 74 mm | 428 g | 360 | n | Mar 2010 | US$ 599 | ebay.com | |
| 14. | Panasonic GF2 | 113 mm | 68 mm | 33 mm | 310 g | 300 | n | Nov 2010 | US$ 549 | ebay.com | |
| 15. | Panasonic GF3 | 108 mm | 67 mm | 32 mm | 264 g | 300 | n | Jun 2011 | US$ 549 | ebay.com | |
| 16. | Panasonic GF5 | 108 mm | 67 mm | 37 mm | 267 g | 360 | n | Apr 2012 | US$ 499 | ebay.com | |
| 17. | Panasonic GH5 | 139 mm | 98 mm | 87 mm | 725 g | 410 | Y | Jan 2017 | US$ 1 999 | ebay.com | |
| Note: 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 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-PM1 was launched at a markedly lower price (by 77 percent) than the OM-1, 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.
Sensor comparison
The size of the imaging sensor is a crucial determinant 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. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its background. On the downside, larger sensors are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.
Both cameras under consideration feature a Four Thirds sensor and have a format factor (sometimes also referred to as "crop factor") of 2.0. 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 feature a native aspect ratio (sensor width to sensor height) of 4:3.
Technology-wise, the OM-1 uses a more advanced image processing engine (TruePic X) than the E-PM1 (TruePic VI), with benefits for noise reduction, color accuracy, and processing speed.

While the two cameras under review share the same sensor size, the OM-1 offers a higher resolution of 20.2 megapixels, compared with 12.2 MP of the E-PM1. This megapixels advantage translates into a 29 percent gain in linear resolution. On the other hand, these sensor specs imply that the OM-1 has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.34μm versus 4.29μm for the E-PM1). However, it should be noted that the OM-1 is much more recent (by 10 years and 7 months) than the E-PM1, and its sensor will have benefitted from technological advances during this time that compensate for the smaller pixel size. Coming back to sensor resolution, it should be mentioned that the OM-1 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the OM System OM-1 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the OM-1 for good quality output (200 dots per inch) amounts to 25.9 x 19.4 inches or 65.8 x 49.4 cm, for very good quality (250 dpi) 20.7 x 15.6 inches or 52.7 x 39.5 cm, and for excellent quality (300 dpi) 17.3 x 13 inches or 43.9 x 32.9 cm. The corresponding values for the Olympus E-PM1 are 20.2 x 15.1 inches or 51.2 x 38.4 cm for good quality, 16.1 x 12.1 inches or 41 x 30.7 cm for very good quality, and 13.4 x 10.1 inches or 34.1 x 25.6 cm for excellent quality prints.
The OM-1 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
Unlike the E-PM1, the OM-1 has the capacity to capture high quality composite images (80MP) by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).
The Olympus PEN E-PM1 has a native sensitivity range from ISO 100 to ISO 12800. The corresponding ISO settings for the OM System OM-1 are ISO 80 to ISO 25600, with the possibility to increase the ISO range to 80-102400.
In terms of underlying technology, the E-PM1 is build around a CMOS sensor, while the OM-1 uses a Stacked BSI-CMOS imager. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.

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"). The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

| Camera Model |
Sensor Class |
Resolution (MP) |
Horiz. Pixels |
Vert. Pixels |
Video Format |
DXO Portrait |
DXO Landscape |
DXO Sports |
DXO Overall |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Olympus E-PM1 | Four Thirds | 12.2 | 4032 | 3024 | 1080/60i | 21.0 | 10.3 | 499 | 52 | |
| 2. | OM System OM-1 | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.4 | 13.4 | 1553 | 77 | |
| 3. | Olympus E-M1 II | Four Thirds | 20.2 | 5184 | 3888 | 4K/30p | 23.7 | 12.8 | 1312 | 80 | |
| 4. | Olympus E-M1 III | Four Thirds | 20.2 | 5184 | 3888 | 4K/30p | 23.3 | 13.1 | 1356 | 76 | |
| 5. | Olympus E-P3 | Four Thirds | 12.2 | 4032 | 3024 | 1080/60i | 20.8 | 10.1 | 536 | 51 | |
| 6. | Olympus E-PL1 | Four Thirds | 12.2 | 4032 | 3024 | 720/30p | 21.5 | 10.1 | 487 | 54 | |
| 7. | Olympus E-PL2 | Four Thirds | 12.2 | 4032 | 3024 | 720/30p | 21.4 | 10.2 | 573 | 55 | |
| 8. | Olympus E-PL3 | Four Thirds | 12.2 | 4032 | 3024 | 1080/60i | 20.9 | 10.3 | 499 | 52 | |
| 9. | Olympus E-PL5 | Four Thirds | 15.9 | 4608 | 3456 | 1080/30p | 22.8 | 12.3 | 889 | 72 | |
| 10. | Olympus E-PM2 | Four Thirds | 15.9 | 4608 | 3456 | 1080/30p | 22.7 | 12.2 | 932 | 72 | |
| 11. | OM System OM-1 II | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.4 | 13.6 | 1749 | 78 | |
| 12. | OM System OM-3 | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.4 | 13.7 | 1852 | 78 | |
| 13. | Panasonic G2 | Four Thirds | 12.0 | 4000 | 3000 | 720/30p | 21.2 | 10.3 | 493 | 53 | |
| 14. | Panasonic GF2 | Four Thirds | 12.0 | 4000 | 3000 | 1080/60i | 21.2 | 10.3 | 506 | 54 | |
| 15. | Panasonic GF3 | Four Thirds | 12.0 | 4000 | 3000 | 1080/60i | 20.6 | 10.1 | 459 | 50 | |
| 16. | Panasonic GF5 | Four Thirds | 12.0 | 4000 | 3000 | 1080/60i | 20.5 | 10.0 | 573 | 50 | |
| 17. | Panasonic GH5 | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.9 | 13.0 | 807 | 77 | |
| Note: DXO values in italics represent estimates based on sensor size and age. | |||||||||||
Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the OM-1 provides a better video resolution than the E-PM1. It can shoot movie footage at 4K/60p, while the Olympus 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 OM-1 has an electronic viewfinder (5760k dots), which can be very helpful when shooting in bright sunlight. In contrast, the E-PM1 relies on live view and the rear LCD for framing. That said, the E-PM1 can be equipped with an optional viewfinder – the VF-2. The following table reports on some other key feature differences and similarities of the Olympus E-PM1, the OM System OM-1, and comparable cameras.

| Camera Model |
Viewfinder (Type or 000 dots) |
Control Panel (yes/no) |
LCD Specifications (inch/000 dots) |
LCD Attach- ment |
Touch Screen (yes/no) |
Max Shutter Speed * |
Max Shutter Flaps * |
Built-in Flash (yes/no) |
Built-in Image Stab |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Olympus E-PM1 | optional | n | 3.0 / 460 | fixed | n | 1/4000s | 5.5/s | n | Y | |
| 2. | OM System OM-1 | 5760 | n | 3.0 / 1640 | swivel | Y | 1/8000s | 10.0/s | n | Y | |
| 3. | Olympus E-M1 II | 2360 | n | 3.0 / 1037 | swivel | Y | 1/8000s | 18.0/s | n | Y | |
| 4. | Olympus E-M1 III | 2360 | n | 3.0 / 1037 | swivel | Y | 1/8000s | 18.0/s | n | Y | |
| 5. | Olympus E-P3 | optional | n | 3.0 / 614 | fixed | Y | 1/4000s | 3.0/s | Y | Y | |
| 6. | Olympus E-PL1 | optional | n | 2.7 / 230 | fixed | n | 1/2000s | 3.0/s | Y | Y | |
| 7. | Olympus E-PL2 | optional | n | 3.0 / 460 | fixed | n | 1/4000s | 3.0/s | Y | Y | |
| 8. | Olympus E-PL3 | optional | n | 3.0 / 460 | tilting | n | 1/4000s | 5.5/s | n | Y | |
| 9. | Olympus E-PL5 | optional | n | 3.0 / 460 | tilting | Y | 1/4000s | 8.0/s | n | Y | |
| 10. | Olympus E-PM2 | optional | n | 3.0 / 460 | fixed | Y | 1/4000s | 8.0/s | n | Y | |
| 11. | OM System OM-1 II | 5760 | n | 3.0 / 1640 | swivel | Y | 1/8000s | 10.0/s | n | Y | |
| 12. | OM System OM-3 | 2360 | n | 3.0 / 1640 | swivel | Y | 1/8000s | 6.0/s | n | Y | |
| 13. | Panasonic G2 | 1440 | n | 3.0 / 460 | swivel | Y | 1/4000s | 2.6/s | Y | n | |
| 14. | Panasonic GF2 | optional | n | 3.0 / 460 | fixed | Y | 1/4000s | 2.6/s | Y | n | |
| 15. | Panasonic GF3 | none | n | 3.0 / 460 | fixed | Y | 1/4000s | 3.2/s | Y | n | |
| 16. | Panasonic GF5 | none | n | 3.0 / 920 | fixed | Y | 1/4000s | 4.0/s | Y | n | |
| 17. | Panasonic GH5 | 3680 | n | 3.2 / 1620 | swivel | Y | 1/8000s | 12.0/s | n | Y | |
| Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one. | |||||||||||
One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The OM-1 has a touchscreen, while the E-PM1 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.
The OM-1 has an articulated screen that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in taking selfies. In contrast, the E-PM1 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 OM-1 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 OM System OM-1 has 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-PM1 and the OM-1 write their files to SDXC cards. The OM-1 features dual card slots, which can be very useful in case a memory card fails. In contrast, the E-PM1 only has one slot. The OM-1 supports UHS-II cards (on both slots), while the E-PM1 cannot take advantage of Ultra High Speed SD cards.
Connectivity comparison
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 PEN E-PM1 and OM System OM-1 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

| Camera Model |
Hotshoe Port |
Internal Mic / Speaker |
Microphone Port |
Headphone Port |
HDMI Port |
USB Port |
WiFi Support |
NFC Support |
Bluetooth Support |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Olympus E-PM1 | Y | stereo / mono | - | - | mini | 2.0 | - | - | - | |
| 2. | OM System OM-1 | Y | stereo / mono | Y | Y | micro | 3.0 | Y | - | Y | |
| 3. | Olympus E-M1 II | Y | stereo / mono | Y | Y | micro | 3.0 | Y | - | - | |
| 4. | Olympus E-M1 III | Y | stereo / mono | Y | Y | micro | 3.1 | Y | - | Y | |
| 5. | Olympus E-P3 | Y | stereo / - | - | - | mini | 2.0 | - | - | - | |
| 6. | Olympus E-PL1 | Y | stereo / - | - | - | mini | 2.0 | - | - | - | |
| 7. | Olympus E-PL2 | Y | stereo / - | - | - | mini | 2.0 | - | - | - | |
| 8. | Olympus E-PL3 | Y | stereo / - | - | - | mini | 2.0 | - | - | - | |
| 9. | Olympus E-PL5 | Y | stereo / mono | - | - | mini | 2.0 | - | - | - | |
| 10. | Olympus E-PM2 | Y | stereo / mono | - | - | mini | 2.0 | - | - | - | |
| 11. | OM System OM-1 II | Y | stereo / mono | Y | Y | micro | 3.0 | Y | - | Y | |
| 12. | OM System OM-3 | Y | stereo / mono | Y | Y | micro | 3.0 | Y | - | Y | |
| 13. | Panasonic G2 | Y | stereo / mono | - | - | mini | 2.0 | - | - | - | |
| 14. | Panasonic GF2 | Y | stereo / mono | - | - | mini | 2.0 | - | - | - | |
| 15. | Panasonic GF3 | - | stereo / mono | - | - | mini | 2.0 | - | - | - | |
| 16. | Panasonic GF5 | - | stereo / mono | - | - | mini | 2.0 | - | - | - | |
| 17. | Panasonic GH5 | Y | stereo / mono | Y | Y | full | 3.1 | Y | - | Y |
It is notable that the OM-1 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the E-PM1 does not provide wifi capability.
Studio photographers will appreciate that the OM System OM-1 (unlike the E-PM1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the E-PM1 and the OM-1 have been discontinued, but can regularly be found used on ebay. The E-PM1 was replaced by the Olympus E-PM2, while the OM-1 was followed by the OM System OM-1 II. Further information on the features and operation of the E-PM1 and OM-1 can be found, respectively, in the Olympus E-PM1 Manual (free pdf) or the online OM System OM-1 Manual.
Review summary
So what conclusions can be drawn? Which of the two cameras – the Olympus E-PM1 or the OM System OM-1 – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Olympus PEN E-PM1:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- More compact: Is smaller (110x64mm vs 135x92mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 334g or 56 percent) and hence easier to carry around.
- More affordable: Was introduced into a lower priced category (77 percent cheaper at launch).
- More heavily discounted: Has been available for much longer (launched in June 2011).

Reasons to prefer the OM System OM-1:
- More detail: Has more megapixels (20.2 vs 12.2MP), which boosts linear resolution by 29%.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- High quality composites: Can combine several shots after pixel-shifting its sensor.
- Better jpgs: Has a more modern image processing engine (TruePic X vs TruePic VI).
- Better video: Provides higher definition movie capture (4K/60p vs 1080/60i).
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- Better sound: Can connect to an external microphone for higher quality sound recording.
- Better sound control: Has a headphone port that enables audio monitoring while recording.
- Easier framing: Has an electronic viewfinder for image composition and settings control.
- More detailed LCD: Has a higher resolution rear screen (1640k vs 460k dots).
- More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (10 vs 5.5 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- Longer lasting: Gets more shots (520 versus 330) out of a single battery charge.
- Easier travel charging: Can be conveniently charged via its USB port.
- Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
- Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
- 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.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- Faster buffer clearing: Supports Ultra High Speed (UHS-II) SDXC cards on both slots.
- More modern: Reflects 10 years and 7 months of technical progress since the E-PM1 launch.
If the count of relative strengths (bullet points above) is taken as a measure, the OM-1 is the clear winner of the contest (27 : 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 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-PM1 and the OM System OM-1 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera listing 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-PM1 or the OM-1 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.
Expert reviews
This is why expert reviews 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], digitalcameraworld [DCW], 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.

| Camera Model |
AP score |
CL score |
DCW score |
DPR score |
EPZ score |
PB score |
Camera Launch |
Launch Price |
Street Price |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Olympus E-PM1 | .. | 86/100 | .. | 71/100 | 4.5/5 | 4.5/5 | Jun 2011 | US$ 499 | ebay.com | |
| 2. | OM System OM-1 | 5/5 | .. | .. | 87/100 | 5/5 | 4.5/5 | Feb 2022 | US$ 2 199 | ebay.com | |
| 3. | Olympus E-M1 II | 5/5 | + + | 5/5 | 85/100 | 4.5/5 | 4.5/5 | Sep 2016 | US$ 1 999 | ebay.com | |
| 4. | Olympus E-M1 III | 5/5 | .. | 5/5 | 83/100 | 4.5/5 | 4/5 | Feb 2020 | US$ 1 799 | ebay.com | |
| 5. | Olympus E-P3 | .. | 83/100 | .. | 74/100 | 4.5/5 | 4.5/5 | Jun 2011 | US$ 799 | ebay.com | |
| 6. | Olympus E-PL1 | .. | 86/100 | .. | 69/100 | 4/5 | 4.5/5 | Feb 2010 | US$ 599 | ebay.com | |
| 7. | Olympus E-PL2 | 3/5 | 83/100 | .. | 71/100 | 4.5/5 | 4.5/5 | Jan 2011 | US$ 599 | ebay.com | |
| 8. | Olympus E-PL3 | 3/5 | + + | .. | 72/100 | 4.5/5 | 4/5 | Jun 2011 | US$ 599 | ebay.com | |
| 9. | Olympus E-PL5 | 3/5 | + + | .. | .. | 4.5/5 | 4.5/5 | Sep 2012 | US$ 599 | ebay.com | |
| 10. | Olympus E-PM2 | 3/5 | .. | .. | 77/100 | 5/5 | 4.5/5 | Sep 2012 | US$ 499 | ebay.com | |
| 11. | OM System OM-1 II | .. | .. | .. | .. | .. | .. | Jan 2024 | US$ 2 399 | amazon.com | |
| 12. | OM System OM-3 | .. | .. | .. | 86/100 | .. | .. | Feb 2025 | US$ 1 999 | amazon.com | |
| 13. | Panasonic G2 | .. | .. | .. | 72/100 | 4/5 | 4.5/5 | Mar 2010 | US$ 599 | ebay.com | |
| 14. | Panasonic GF2 | 3/5 | 82/100 | .. | 70/100 | 4.5/5 | 4.5/5 | Nov 2010 | US$ 549 | ebay.com | |
| 15. | Panasonic GF3 | 3/5 | 82/100 | .. | 71/100 | 4.5/5 | 4/5 | Jun 2011 | US$ 549 | ebay.com | |
| 16. | Panasonic GF5 | 3/5 | .. | .. | .. | 4.5/5 | 4.5/5 | Apr 2012 | US$ 499 | ebay.com | |
| 17. | Panasonic GH5 | 4.5/5 | + + | .. | 85/100 | 4.5/5 | 5/5 | Jan 2017 | US$ 1 999 | ebay.com | |
| Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available. | |||||||||||
The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

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Check OM-1 offers at
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Other camera comparisons
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Specifications: Olympus E-PM1 vs OM System OM-1
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-PM1 | OM System OM-1 |
|---|---|---|
| Camera Type | Mirrorless system camera | Mirrorless system camera |
| Camera Lens | Micro Four Thirds lenses | Micro Four Thirds lenses |
| Launch Date | June 2011 | February 2022 |
| Launch Price | USD 499 | USD 2,199 |
| Sensor Specs | Olympus E-PM1 | OM System OM-1 |
| Sensor Technology | CMOS | Stacked BSI-CMOS |
| Sensor Format | Four Thirds Sensor | Four Thirds Sensor |
| Sensor Size | 17.3 x 13.0 mm | 17.3 x 13.0 mm |
| Sensor Area | 224.9 mm2 | 224.9 mm2 |
| Sensor Diagonal | 21.6 mm | 21.6 mm |
| Crop Factor | 2.0x | 2.0x |
| Sensor Resolution | 12.2 Megapixels | 20.2 Megapixels |
| Image Resolution | 4032 x 3024 pixels | 5184 x 3888 pixels |
| Pixel Pitch | 4.29 μm | 3.34 μm |
| Pixel Density | 5.42 MP/cm2 | 8.96 MP/cm2 |
| Moiré control | Anti-Alias filter | no AA filter |
| Movie Capability | 1080/60i Video | 4K/60p Video |
| ISO Setting | 100 - 12,800 ISO | 80 - 25,600 ISO |
| ISO Boost | no Enhancement | 80 - 102,400 ISO |
| Image Processor | TruePic VI | TruePic X |
| DXO Sensor Quality (score) | 52 | .. |
| DXO Color Depth (bits) | 21.0 | .. |
| DXO Dynamic Range (EV) | 10.3 | .. |
| DXO Low Light (ISO) | 499 | .. |
| Screen Specs | Olympus E-PM1 | OM System OM-1 |
| Viewfinder Type | Viewfinder optional | Electronic viewfinder |
| Viewfinder Field of View | 100% | |
| Viewfinder Magnification | 0.82x | |
| Viewfinder Resolution | 5760k dots | |
| LCD Framing | Live View | Live View |
| Rear LCD Size | 3.0inch | 3.0inch |
| LCD Resolution | 460k dots | 1640k dots |
| LCD Attachment | Fixed screen | Swivel screen |
| Touch Input | no Touchscreen | Touchscreen |
| Shooting Specs | Olympus E-PM1 | OM System OM-1 |
| Focus System | Contrast-detect AF | On-Sensor Phase-detect |
| Manual Focusing Aid | no Peaking Feature | Focus Peaking |
| Max Shutter Speed (mechanical) | 1/4000s | 1/8000s |
| Continuous Shooting | 5.5 shutter flaps/s | 10 shutter flaps/s |
| Electronic Shutter | no E-Shutter | up to 1/32000s |
| Time-Lapse Photography | no Intervalometer | 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 |
| Single or Dual Card Slots | Single card slot | Dual card slots |
| UHS card support | no | Dual UHS-II |
| Connectivity Specs | Olympus E-PM1 | OM System OM-1 |
| External Flash | Hotshoe | Hotshoe |
| Studio Flash | no PC Sync | PC Sync socket |
| USB Connector | USB 2.0 | USB 3.0 |
| HDMI Port | mini HDMI | micro HDMI |
| Microphone Port | no MIC socket | External MIC port |
| Headphone Socket | no Headphone port | Headphone port |
| Wifi Support | no Wifi | Wifi built-in |
| Bluetooth Support | no Bluetooth | Bluetooth built-in |
| Body Specs | Olympus E-PM1 | OM System OM-1 |
| Environmental Sealing | not weather sealed | Weathersealed body |
| Battery Type | Olympus BLS-5 | OM System BLX-1 |
| Battery Life (CIPA) | 330 shots per charge | 520 shots per charge |
| In-Camera Charging | no USB charging | USB charging |
| Body Dimensions |
110 x 64 x 34 mm (4.3 x 2.5 x 1.3 in) |
135 x 92 x 73 mm (5.3 x 3.6 x 2.9 in) |
| Camera Weight | 265 g (9.3 oz) | 599 g (21.1 oz) |

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