Olympus E-M1 III vs Sony A99
The Olympus OM-D E-M1 Mark III and the Sony Alpha SLT-A99 are two digital cameras that were revealed to the public, respectively, in February 2020 and September 2012. The E-M1 III is a mirrorless interchangeable lens camera, while the A99 is a DSLR. The cameras are based on a Four Thirds (E-M1 III) and a full frame (A99) sensor. The Olympus has a resolution of 20.2 megapixels, whereas the Sony provides 24 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 OM-D E-M1 Mark III and the Sony Alpha SLT-A99? 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-M1 III and the Sony A99 is provided in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All size dimensions are rounded to the nearest millimeter.



If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A99 is notably larger (34 percent) than the Olympus E-M1 III. Moreover, the A99 is substantially heavier (40 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 Olympus BLH-1 battery, while the A99 can take 500 images on a single charge of its Sony NP-FM500H 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. In case you want to display and compare another camera duo, you can use the CAM-parator app to select your camera combination among a large number of options.

| Camera Model |
Camera Width |
Camera Height |
Camera Depth |
Camera Weight |
Battery Life |
Weather Sealing |
Camera Launch |
Launch Price |
Street Price |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Olympus E-M1 III | 134 mm | 91 mm | 69 mm | 580 g | 420 | Y | Feb 2020 | US$ 1 799 | ebay.com | |
| 2. | Sony A99 | 147 mm | 111 mm | 78 mm | 812 g | 500 | Y | Sep 2012 | US$ 2 799 | 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-M1X | 144 mm | 147 mm | 75 mm | 997 g | 870 | Y | Jan 2019 | US$ 2 999 | ebay.com | |
| 5. | Olympus E-M5 III | 125 mm | 85 mm | 50 mm | 414 g | 310 | Y | Oct 2019 | US$ 1 199 | ebay.com | |
| 6. | OM System OM-1 | 135 mm | 92 mm | 73 mm | 599 g | 520 | Y | Feb 2022 | US$ 2 199 | ebay.com | |
| 7. | OM System OM-3 | 139 mm | 89 mm | 46 mm | 496 g | 590 | Y | Feb 2025 | US$ 1 999 | amazon.com | |
| 8. | Panasonic G9 | 137 mm | 97 mm | 92 mm | 658 g | 400 | Y | Nov 2017 | US$ 1 699 | ebay.com | |
| 9. | Panasonic G97 | 130 mm | 94 mm | 77 mm | 536 g | 290 | Y | Apr 2019 | US$ 749 | ebay.com | |
| 10. | Panasonic G95 | 130 mm | 94 mm | 77 mm | 536 g | 290 | Y | Apr 2019 | US$ 999 | ebay.com | |
| 11. | Panasonic GH5 | 139 mm | 98 mm | 87 mm | 725 g | 410 | Y | Jan 2017 | US$ 1 999 | ebay.com | |
| 12. | Panasonic GH5 II | 139 mm | 98 mm | 87 mm | 727 g | 400 | Y | May 2021 | US$ 1 699 | amazon.com | |
| 13. | Sony A9 II | 129 mm | 96 mm | 76 mm | 678 g | 690 | Y | Oct 2019 | US$ 4 499 | amazon.com | |
| 14. | Sony A77 | 143 mm | 104 mm | 81 mm | 732 g | 470 | Y | Aug 2011 | US$ 1 399 | ebay.com | |
| 15. | Sony A99 II | 143 mm | 104 mm | 76 mm | 849 g | 490 | Y | Sep 2016 | US$ 3 199 | ebay.com | |
| 16. | Sony A850 | 156 mm | 117 mm | 82 mm | 895 g | 880 | Y | Aug 2009 | US$ 1 999 | ebay.com | |
| 17. | Sony A900 | 156 mm | 117 mm | 82 mm | 895 g | 880 | Y | Sep 2008 | US$ 2 999 | ebay.com | |
| Note: 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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The E-M1 III was launched at a markedly lower price (by 36 percent) than the A99, 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. 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 tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units in a sensor of the same technological generation. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the background. On the downside, larger sensors tend to be more expensive and 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 Sony A99 a full frame sensor. The sensor area in the A99 is 279 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.0. The sensor in the E-M1 III has a native 4:3 aspect ratio, while the one in the A99 offers a 3:2 aspect.

With 24MP, the A99 offers a higher resolution than the E-M1 III (20.2MP), but the A99 nevertheless has larger individual pixels (pixel pitch of 5.96μm 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 7 years and 5 months) than the A99, 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 the E-M1 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the Sony A99 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A99 for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 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.
Unlike the A99, the E-M1 III 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 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 Sony Alpha SLT-A99 are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-25600.
Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors. 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 assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

| Camera Model |
Sensor Class |
Resolution (MP) |
Horiz. Pixels |
Vert. Pixels |
Video Format |
DXO Portrait |
DXO Landscape |
DXO Sports |
DXO Overall |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Olympus E-M1 III | Four Thirds | 20.2 | 5184 | 3888 | 4K/30p | 23.3 | 13.1 | 1356 | 76 | |
| 2. | Sony A99 | Full Frame | 24.0 | 6000 | 4000 | 1080/60p | 25.0 | 14.0 | 1555 | 89 | |
| 3. | Olympus E-M1 II | Four Thirds | 20.2 | 5184 | 3888 | 4K/30p | 23.7 | 12.8 | 1312 | 80 | |
| 4. | Olympus E-M1X | Four Thirds | 20.2 | 5184 | 3888 | 4K/30p | 23.2 | 13.0 | 1254 | 75 | |
| 5. | Olympus E-M5 III | Four Thirds | 20.2 | 5184 | 3888 | 4K/30p | 23.3 | 13.1 | 1324 | 76 | |
| 6. | OM System OM-1 | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.4 | 13.4 | 1553 | 77 | |
| 7. | OM System OM-3 | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.4 | 13.7 | 1852 | 78 | |
| 8. | Panasonic G9 | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.1 | 12.8 | 1138 | 74 | |
| 9. | Panasonic G97 | Four Thirds | 20.2 | 5184 | 3888 | 4K/30p | 23.2 | 13.0 | 1273 | 75 | |
| 10. | Panasonic G95 | Four Thirds | 20.2 | 5184 | 3888 | 4K/30p | 23.2 | 13.0 | 1273 | 75 | |
| 11. | Panasonic GH5 | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.9 | 13.0 | 807 | 77 | |
| 12. | Panasonic GH5 II | Four Thirds | 20.2 | 5184 | 3888 | 4K/60p | 23.7 | 13.1 | 1136 | 79 | |
| 13. | Sony A9 II | Full Frame | 24.0 | 6000 | 4000 | 4K/30p | 25.0 | 14.0 | 3434 | 93 | |
| 14. | Sony A77 | APS-C | 24.0 | 6000 | 4000 | 1080/60p | 24.0 | 13.2 | 801 | 78 | |
| 15. | Sony A99 II | Full Frame | 42.2 | 7952 | 5304 | 4K/30p | 25.4 | 13.4 | 2317 | 92 | |
| 16. | Sony A850 | Full Frame | 24.4 | 6048 | 4032 | none | 23.8 | 12.2 | 1415 | 79 | |
| 17. | Sony A900 | Full Frame | 24.4 | 6048 | 4032 | none | 23.7 | 12.3 | 1431 | 79 | |
| 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 can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the E-M1 III provides a higher video resolution than the A99. It can shoot video footage at 4K/30p, while the Sony is limited to 1080/60p.
Feature comparison
Beyond body and sensor, cameras can and do differ across a range of features. The two cameras under consideration are similar with respect to both having an electronic viewfinder. However, the one in the E-M1 III offers a slightly higher resolution than the one in the A99 (2360k vs 2359k dots). The table below summarizes some of the other core capabilities of the Olympus E-M1 III and Sony A99 in connection with corresponding information for a sample of similar 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-M1 III | 2360 | n | 3.0 / 1037 | swivel | Y | 1/8000s | 18.0/s | n | Y | |
| 2. | Sony A99 | 2359 | Y | 3.0 / 1229 | full-flex | n | 1/8000s | 6.0/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-M1X | 2360 | n | 3.0 / 1037 | swivel | Y | 1/8000s | 18.0/s | n | Y | |
| 5. | Olympus E-M5 III | 2360 | n | 3.0 / 1040 | swivel | Y | 1/8000s | 10.0/s | n | Y | |
| 6. | OM System OM-1 | 5760 | n | 3.0 / 1640 | swivel | Y | 1/8000s | 10.0/s | n | Y | |
| 7. | OM System OM-3 | 2360 | n | 3.0 / 1640 | swivel | Y | 1/8000s | 6.0/s | n | Y | |
| 8. | Panasonic G9 | 3680 | Y | 3.0 / 1040 | swivel | Y | 1/8000s | 20.0/s | n | Y | |
| 9. | Panasonic G97 | 2360 | n | 3.0 / 1840 | swivel | Y | 1/4000s | 9.0/s | Y | Y | |
| 10. | Panasonic G95 | 2360 | n | 3.0 / 1240 | swivel | Y | 1/4000s | 9.0/s | Y | Y | |
| 11. | Panasonic GH5 | 3680 | n | 3.2 / 1620 | swivel | Y | 1/8000s | 12.0/s | n | Y | |
| 12. | Panasonic GH5 II | 3680 | n | 3.0 / 1840 | swivel | Y | 1/8000s | 12.0/s | n | Y | |
| 13. | Sony A9 II | 3686 | n | 3.0 / 1440 | tilting | Y | 1/8000s | 20.0/s | n | Y | |
| 14. | Sony A77 | 2359 | Y | 3.0 / 921 | full-flex | n | 1/8000s | 12.0/s | Y | Y | |
| 15. | Sony A99 II | 2400 | Y | 3.0 / 1229 | full-flex | n | 1/8000s | 12.0/s | n | Y | |
| 16. | Sony A850 | optical | Y | 3.0 / 922 | fixed | n | 1/8000s | 3.0/s | n | Y | |
| 17. | Sony A900 | optical | Y | 3.0 / 922 | fixed | n | 1/8000s | 5.0/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 E-M1 III has a touchscreen, while the A99 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.
Both cameras have an articulated rear screen that can be turned to be front-facing. This feature will be particularly appreciated by vloggers and photographers who are interested in taking selfies.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 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.
The E-M1 III writes its imaging data to SDXC cards, while the A99 uses SDXC or Memory Stick PRO Duo 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 A99 can use UHS-I 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 OM-D E-M1 Mark III and Sony Alpha SLT-A99 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-M1 III | Y | stereo / mono | Y | Y | micro | 3.1 | Y | - | Y | |
| 2. | Sony A99 | Y | stereo / mono | Y | Y | mini | 2.0 | - | - | - | |
| 3. | Olympus E-M1 II | Y | stereo / mono | Y | Y | micro | 3.0 | Y | - | - | |
| 4. | Olympus E-M1X | Y | stereo / mono | Y | Y | micro | 3.0 | Y | - | Y | |
| 5. | Olympus E-M5 III | Y | stereo / mono | Y | - | micro | 2.0 | Y | - | Y | |
| 6. | OM System OM-1 | Y | stereo / mono | Y | Y | micro | 3.0 | Y | - | Y | |
| 7. | OM System OM-3 | Y | stereo / mono | Y | Y | micro | 3.0 | Y | - | Y | |
| 8. | Panasonic G9 | Y | stereo / mono | Y | Y | full | 3.0 | Y | - | Y | |
| 9. | Panasonic G97 | Y | stereo / mono | Y | Y | micro | 2.0 | Y | - | Y | |
| 10. | Panasonic G95 | Y | stereo / mono | Y | Y | micro | 2.0 | Y | - | Y | |
| 11. | Panasonic GH5 | Y | stereo / mono | Y | Y | full | 3.1 | Y | - | Y | |
| 12. | Panasonic GH5 II | Y | stereo / mono | Y | Y | full | 3.2 | Y | - | Y | |
| 13. | Sony A9 II | Y | stereo / mono | Y | Y | micro | 3.1 | Y | Y | Y | |
| 14. | Sony A77 | Y | stereo / mono | Y | - | mini | 2.0 | - | - | - | |
| 15. | Sony A99 II | Y | stereo / mono | Y | Y | micro | 2.0 | Y | Y | Y | |
| 16. | Sony A850 | Y | - / - | - | - | mini | 2.0 | - | - | - | |
| 17. | Sony A900 | Y | - / - | - | - | mini | 2.0 | - | - | - |
It is notable that the E-M1 III offers wifi support, while the A99 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 A99 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.
Both the E-M1 III and the A99 have been discontinued, but can regularly be found used on ebay. The A99 was replaced by the Sony A99, while the E-M1 III was followed by the OM System OM-1. Further information on the features and operation of the E-M1 III and A99 can be found, respectively, in the Olympus E-M1 III Manual (free pdf) or the online Sony A99 Manual.
Review summary
So how do things add up? Is there a clear favorite between the Olympus E-M1 III and the Sony A99? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Olympus OM-D E-M1 Mark III:
- 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 video: Provides higher definition movie capture (4K/30p vs 1080/60p).
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.74x vs 0.71x).
- Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
- Faster burst: Shoots at higher frequency (18 vs 6 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.
- More compact: Is smaller (134x91mm vs 147x111mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 232g or 29 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.
- Faster data transfer: Supports a more advanced USB protocol (3.1 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.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- More affordable: Was introduced into a lower priced category (36 percent cheaper at launch).
- More modern: Reflects 7 years and 5 months of technical progress since the A99 launch.

Reasons to prefer the Sony Alpha SLT-A99:
- More detail: Has more megapixels (24 vs 20.2MP), which boosts linear resolution by 11%.
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Easier setting verification: Features a control panel on top to check shooting parameters.
- More detailed LCD: Has a higher resolution rear screen (1229k vs 1037k dots).
- Longer lasting: Gets more shots (500 versus 420) out of a single battery charge.
- Easier geotagging: Features an internal GPS sensor to log localization data.
- More heavily discounted: Has been around for much longer (launched in September 2012).
If the count of relative strengths (bullet points above) is taken as a measure, the E-M1 III is the clear winner of the match-up (19 : 7 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 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 III and the Sony A99 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 technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the E-M1 III and the A99 in practical situations. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.
Expert reviews
This is where reviews by experts come in. 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-M1 III | 5/5 | .. | 5/5 | 83/100 | 4.5/5 | 4/5 | Feb 2020 | US$ 1 799 | ebay.com | |
| 2. | Sony A99 | 5/5 | .. | .. | 84/100 | 4.5/5 | 4.5/5 | Sep 2012 | US$ 2 799 | 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-M1X | 4.5/5 | o | 5/5 | 85/100 | 4.5/5 | .. | Jan 2019 | US$ 2 999 | ebay.com | |
| 5. | Olympus E-M5 III | 5/5 | + | 5/5 | 82/100 | 4.5/5 | 4.5/5 | Oct 2019 | US$ 1 199 | ebay.com | |
| 6. | OM System OM-1 | 5/5 | .. | .. | 87/100 | 5/5 | 4.5/5 | Feb 2022 | US$ 2 199 | ebay.com | |
| 7. | OM System OM-3 | .. | .. | .. | 86/100 | .. | .. | Feb 2025 | US$ 1 999 | amazon.com | |
| 8. | Panasonic G9 | .. | + + | 5/5 | 85/100 | 5/5 | 5/5 | Nov 2017 | US$ 1 699 | ebay.com | |
| 9. | Panasonic G97 | .. | .. | .. | .. | .. | .. | Apr 2019 | US$ 749 | ebay.com | |
| 10. | Panasonic G95 | 4.5/5 | + | 4.5/5 | 83/100 | 4.5/5 | 4.5/5 | Apr 2019 | US$ 999 | ebay.com | |
| 11. | Panasonic GH5 | 4.5/5 | + + | .. | 85/100 | 4.5/5 | 5/5 | Jan 2017 | US$ 1 999 | ebay.com | |
| 12. | Panasonic GH5 II | 4.5/5 | .. | 4.5/5 | 85/100 | 4.5/5 | 5/5 | May 2021 | US$ 1 699 | amazon.com | |
| 13. | Sony A9 II | .. | .. | 5/5 | 90/100 | 5/5 | 5/5 | Oct 2019 | US$ 4 499 | amazon.com | |
| 14. | Sony A77 | 5/5 | 91/100 | .. | 81/100 | .. | 5/5 | Aug 2011 | US$ 1 399 | ebay.com | |
| 15. | Sony A99 II | .. | .. | 4.5/5 | 85/100 | 4.5/5 | 4.5/5 | Sep 2016 | US$ 3 199 | ebay.com | |
| 16. | Sony A850 | 3/5 | .. | .. | 75/100 | .. | 4.5/5 | Aug 2009 | US$ 1 999 | ebay.com | |
| 17. | Sony A900 | .. | + + | .. | + + | 4.5/5 | 5/5 | Sep 2008 | US$ 2 999 | 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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Check E-M1 III offers at
ebay.com

Check A99 offers at
ebay.com
Other camera comparisons
Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.
- Canon 5D vs Sony A99
- Canon 5DS vs Olympus E-M1 III
- Canon M6 vs Sony A99
- Canon R3 vs Sony A99
- Fujifilm XP130 vs Olympus E-M1 III
- Nikon 1 V1 vs Olympus E-M1 III
- Nikon Z fc vs Olympus E-M1 III
- Nikon Z50 vs Olympus E-M1 III
- Olympus E-M1 III vs Panasonic GH7
- Olympus XZ-2 vs Sony A99
- Sony A6400 vs Sony A99
- Sony A850 vs Sony A99
Specifications: Olympus E-M1 III vs Sony A99
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 | Sony A99 |
|---|---|---|
| Camera Type | Mirrorless system camera | Digital single lens reflex |
| Camera Lens | Micro Four Thirds lenses | Sony A mount lenses |
| Launch Date | February 2020 | September 2012 |
| Launch Price | USD 1,799 | USD 2,799 |
| Sensor Specs | Olympus E-M1 III | Sony A99 |
| Sensor Technology | CMOS | CMOS |
| Sensor Format | Four Thirds Sensor | Full Frame Sensor |
| Sensor Size | 17.3 x 13.0 mm | 35.8 x 23.8 mm |
| Sensor Area | 224.9 mm2 | 852.04 mm2 |
| Sensor Diagonal | 21.6 mm | 43 mm |
| Crop Factor | 2.0x | 1.0x |
| Sensor Resolution | 20.2 Megapixels | 24 Megapixels |
| Image Resolution | 5184 x 3888 pixels | 6000 x 4000 pixels |
| Pixel Pitch | 3.34 μm | 5.96 μm |
| Pixel Density | 8.96 MP/cm2 | 2.82 MP/cm2 |
| Moiré control | no AA filter | Anti-Alias filter |
| Movie Capability | 4K/30p Video | 1080/60p Video |
| ISO Setting | 200 - 25,600 ISO | 100 - 25,600 ISO |
| ISO Boost | 64 - 25,600 ISO | 50 - 25,600 ISO |
| Image Processor | TruePic IX | BIONZ X |
| DXO Sensor Quality (score) | .. | 89 |
| DXO Color Depth (bits) | .. | 25.0 |
| DXO Dynamic Range (EV) | .. | 14.0 |
| DXO Low Light (ISO) | .. | 1555 |
| Screen Specs | Olympus E-M1 III | Sony A99 |
| Viewfinder Type | Electronic viewfinder | Electronic viewfinder |
| Viewfinder Field of View | 100% | 100% |
| Viewfinder Magnification | 0.74x | 0.71x |
| Viewfinder Resolution | 2360k dots | 2359k dots |
| Top-Level Screen | no Top Display | Control Panel |
| LCD Framing | Live View | Live View |
| Rear LCD Size | 3.0inch | 3.0inch |
| LCD Resolution | 1037k dots | 1229k dots |
| LCD Attachment | Swivel screen | Fully flexible screen |
| Touch Input | Touchscreen | no Touchscreen |
| Shooting Specs | Olympus E-M1 III | Sony A99 |
| 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 | 6 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 | no Intervalometer |
| Image Stabilization | In-body stabilization | In-body stabilization |
| Fill Flash | no On-Board Flash | no On-Board Flash |
| Storage Medium | SDXC cards | MS or SDXC cards |
| Single or Dual Card Slots | Dual card slots | Dual card slots |
| UHS card support | Single UHS-II | UHS-I |
| Connectivity Specs | Olympus E-M1 III | Sony A99 |
| External Flash | Hotshoe | Hotshoe |
| Studio Flash | PC Sync socket | PC Sync socket |
| USB Connector | USB 3.1 | USB 2.0 |
| 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 | Sony A99 |
| Environmental Sealing | Weathersealed body | Weathersealed body |
| Battery Type | Olympus BLH-1 | Sony NP-FM500H |
| Battery Life (CIPA) | 420 shots per charge | 500 shots per charge |
| In-Camera Charging | USB charging | no USB charging |
| Body Dimensions |
134 x 91 x 69 mm (5.3 x 3.6 x 2.7 in) |
147 x 111 x 78 mm (5.8 x 4.4 x 3.1 in) |
| Camera Weight | 580 g (20.5 oz) | 812 g (28.6 oz) |

Check E-M1 III offers at
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Check A99 offers at
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