Sony A7 vs Olympus E-M1

The Sony Alpha A7 and the Olympus OM-D E-M1 are two enthusiast cameras that were revealed to the public, respectively, in October 2013 and September 2013. Both the A7 and the E-M1 are mirrorless interchangeable lens cameras that are based on a full frame (A7) and a Four Thirds (E-M1) sensor. The Sony has a resolution of 24 megapixels, whereas the Olympus provides 15.9 MP.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Sony A7		Olympus E-M1
Mirrorless system camera		Mirrorless system camera
Sony E mount lenses		Micro Four Thirds lenses
24 MP – Full Frame sensor		15.9 MP – Four Thirds sensor
1080/60p Video		1080/30p Video
ISO 100-25,600 (50 - 51,200)		ISO 200-25,600
Electronic viewfinder (2400k dots)		Electronic viewfinder (2360k dots)
3.0" LCD – 1230k dots		3.0" LCD – 1037k dots
Tilting screen (no touchscreen)		Tilting touchscreen
5 shutter flaps per second		10 shutter flaps per second
Lens stabilization only		In-body stabilization
Weathersealed body		Weathersealed body
340 shots per battery charge		350 shots per battery charge
127 x 94 x 48 mm, 474 g		130 x 94 x 63 mm, 497 g

Check A7 offers at
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Check E-M1 offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A7 and the Olympus OM-D E-M1? 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 Sony A7 and the Olympus E-M1 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 size dimensions are rounded to the nearest millimeter.

The E-M1 can be obtained in two different colors (black, silver), while the A7 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 Olympus E-M1 is somewhat larger (2 percent) than the Sony A7. Moreover, the E-M1 is markedly heavier (5 percent) than the A7. 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. A larger imaging sensor will tend to go along with bigger and heavier lenses, although exceptions exist. You can compare the optics available for the two cameras in the Sony FE Lens Catalog (A7) and the Micro Four Thirds Lens Catalog (E-M1). 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 A7 gets 340 shots out of its Sony NP-FW50 battery, while the E-M1 can take 350 images on a single charge of its Olympus BLN-1 power pack. The power pack in the A7 can be charged via the USB port, so that it is not always necessary to take the battery charger along when travelling.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price (USD)	Street Price
1.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	1,699	ebay.com
2.		Olympus E-M1	130 mm	94 mm	63 mm	497 g	350	Y	Sep 2013	1,399	ebay.com
3.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
4.		Olympus E-M1 II	134 mm	91 mm	67 mm	574 g	440	Y	Sep 2016	1,999	ebay.com
5.		Olympus E-M5	122 mm	89 mm	43 mm	425 g	360	Y	Feb 2012	1,299	ebay.com
6.		Olympus E-M5 II	124 mm	85 mm	45 mm	469 g	310	Y	Feb 2015	1,099	ebay.com
7.		Olympus E-P5	122 mm	69 mm	37 mm	420 g	330	n	May 2013	999	ebay.com
8.		Olympus PEN-F	125 mm	72 mm	37 mm	427 g	330	n	Jan 2016	1,199	ebay.com
9.		Panasonic GH4	133 mm	93 mm	84 mm	560 g	500	Y	Feb 2014	1,499	ebay.com
10.		Samsung NX1	139 mm	102 mm	66 mm	550 g	500	Y	Sep 2014	1,499	ebay.com
11.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999	ebay.com
12.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	1,999	amazon.com
13.		Sony A7C	124 mm	71 mm	60 mm	509 g	740	Y	Sep 2020	1,799	amazon.com
14.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	2,299	ebay.com
15.		Sony A7S	127 mm	94 mm	48 mm	489 g	380	Y	Apr 2014	2,499	ebay.com
16.		Sony RX1	113 mm	65 mm	70 mm	482 g	270	n	Sep 2012	2,799	ebay.com
17.		Sony RX1R	113 mm	65 mm	70 mm	482 g	270	n	Jun 2013	2,799	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
Convert to Imperial

Any camera decision will naturally be influenced heavily by the price. 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 somewhat lower price (by 18 percent) than the A7, which makes it more attractive for photographers on a tight budget. 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors of image quality. A large sensor will generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have richer color-depth than smaller pixels in a sensor of the same technological generation. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better isolate a subject from the background. On the downside, larger sensors tend to be more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A7 features a full frame sensor and the Olympus E-M1 a Four Thirds sensor. The sensor area in the E-M1 is 74 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 2.0. The sensor in the A7 has a native 3:2 aspect ratio, while the one in the E-M1 offers a 4:3 aspect.

With 24MP, the A7 offers a higher resolution than the E-M1 (15.9MP), but the A7 nevertheless has larger individual pixels (pixel pitch of 5.97μm versus 3.76μm for the E-M1) due to its larger sensor. It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation. Coming back to sensor resolution, it should be mentioned that the E-M1 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Sony A7 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7 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 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 Sony Alpha A7 has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 50-51200. The corresponding ISO settings for the Olympus OM-D E-M1 are ISO 200 to ISO 25600, with the possibility to increase the ISO range to 100-25600.

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 determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). Of the two cameras under review, the A7 provides substantially higher image quality than the E-M1, with an overall score that is 17 points higher. This advantage is based on 1.8 bits higher color depth, 1.5 EV in additional dynamic range, and 1.6 stops in additional low light sensitivity. The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90
2.		Olympus E-M1	Four Thirds	15.9	4608	3456	1080/30p	23.0	12.7	757	73
3.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
4.		Olympus E-M1 II	Four Thirds	20.2	5184	3888	4K/30p	23.7	12.8	1312	80
5.		Olympus E-M5	Four Thirds	15.9	4608	3456	1080/60i	22.8	12.3	826	71
6.		Olympus E-M5 II	Four Thirds	15.9	4608	3456	1080/60p	23.0	12.5	842	73
7.		Olympus E-P5	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.4	895	72
8.		Olympus PEN-F	Four Thirds	20.2	5184	3888	1080/60p	23.1	12.4	894	74
9.		Panasonic GH4	Four Thirds	15.9	4608	3456	4K/30p	23.2	12.8	791	74
10.		Samsung NX1	APS-C	28.0	6480	4320	4K/30p	24.2	13.2	1363	83
11.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
12.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
13.		Sony A7C	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3407	95
14.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95
15.		Sony A7S	Full Frame	12.0	4240	2832	1080/60p	23.9	13.2	3702	87
16.		Sony RX1	Full Frame	24.0	6000	4000	1080/60p	25.1	14.3	2534	93
17.		Sony RX1R	Full Frame	24.0	6000	4000	1080/60p	25.0	13.6	2537	91

Many modern cameras are not only capable of taking still images, but can also record movies. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A7 provides a higher frame rate than the E-M1. It can shoot video footage at 1080/60p, while the Olympus is limited to 1080/30p.

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 A7 offers a slightly higher resolution than the one in the E-M1 (2400k vs 2360k dots). The adjacent table lists some of the other core features of the Sony A7 and Olympus E-M1 along with similar information for a selection of comparators.

Core Features

		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.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
2.		Olympus E-M1	2360	n	3.0 / 1037	tilting	Y	1/8000s	10.0/s	n	Y
3.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
4.		Olympus E-M1 II	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
5.		Olympus E-M5	1440	n	3.0 / 610	tilting	Y	1/4000s	9.0/s	n	Y
6.		Olympus E-M5 II	2360	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
7.		Olympus E-P5	optional	n	3.0 / 1037	tilting	Y	1/8000s	9.0/s	Y	Y
8.		Olympus PEN-F	2360	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
9.		Panasonic GH4	2359	n	3.0 / 1036	swivel	Y	1/8000s	12.0/s	Y	n
10.		Samsung NX1	2360	Y	3.0 / 1036	tilting	Y	1/8000s	15.0/s	Y	n
11.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
12.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
13.		Sony A7C	2360	n	3.0 / 922	swivel	Y	1/4000s	10.0/s	n	Y
14.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
15.		Sony A7S	2400	n	3.0 / 921	tilting	n	1/8000s	5.0/s	n	n
16.		Sony RX1	optional	n	3.0 / 1229	fixed	n	1/4000s	5.0/s	Y	n
17.		Sony RX1R	optional	n	3.0 / 1229	fixed	n	1/4000s	5.0/s	Y	n
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 has a touchscreen, while the A7 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

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 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 A7 writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the E-M1 uses SDXC cards. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.

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 Sony Alpha A7 and Olympus OM-D E-M1 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

Input-Output Connections

		Camera Model	Hotshoe Port	Internal Mic / Speaker	Microphone Port	Headphone Port	HDMI Port	USB Port	WiFi Support	NFC Support	Bluetooth Support
1.		Sony A7	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
2.		Olympus E-M1	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
3.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
4.		Olympus E-M1 II	Y	stereo / mono	Y	Y	micro	3.0	Y	-	-
5.		Olympus E-M5	Y	stereo / mono	-	-	mini	2.0	-	-	-
6.		Olympus E-M5 II	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
7.		Olympus E-P5	Y	stereo / mono	-	-	micro	2.0	Y	-	-
8.		Olympus PEN-F	Y	stereo / mono	-	-	micro	2.0	Y	-	-
9.		Panasonic GH4	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
10.		Samsung NX1	Y	stereo / mono	Y	Y	micro	3.0	Y	Y	Y
11.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
12.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
13.		Sony A7C	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
14.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A7S	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony RX1	Y	stereo / mono	Y	-	mini	2.0	-	-	-
17.		Sony RX1R	Y	stereo / mono	Y	-	mini	2.0	-	-	-

It is notable that the A7 has a headphone jack, which is not present on the E-M1 This port makes it possible to attach external headphones and monitor the quality of sound during the recording process.

Studio photographers will appreciate that the Olympus E-M1 (unlike the A7) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the A7 and the E-M1 have been discontinued, but can regularly be found used on ebay. The E-M1 was replaced by the Olympus E-M1 II, while the A7 was followed by the Sony A7 II. Further information on the features and operation of the A7 and E-M1 can be found, respectively, in the Sony A7 Manual (free pdf) or the online Olympus E-M1 Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Sony A7 or the Olympus E-M1 – 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.

Advantages of the Sony Alpha A7:

• More detail: Offers more megapixels (24 vs 15.9MP) with a 25% higher linear resolution.
• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better image quality: Scores substantially higher (17 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (1.8 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (1.5 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (1.6 stops ISO advantage).
• Better video: Provides higher movie framerates (1080/60p versus 1080/30p).
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• More detailed LCD: Has a higher resolution rear screen (1230k vs 1037k dots).
• Easier travel charging: Can be conveniently charged via its USB port.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.

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

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.74x vs 0.71x).
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• Faster burst: Shoots at higher frequency (10 vs 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.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More affordable: Was released into a lower priced segment (18 percent cheaper at launch).

If the count of individual advantages (bullet points above) is taken as a guide, the A7 emerges as the winner of the contest (11 : 9 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. A professional sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 Sony A7 and the Olympus E-M1 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 A7 or the E-M1 perform in practice. 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.

Expert reviews

This is where reviews by experts come in. The table below provides a synthesis of the camera assessments of some of the best known photo-gear 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.

Expert Camera Reviews

		Camera   Model	AP   score	CL   score	DCW   score	DPR   score	EPZ   score	PB   score	Camera Launch	Launch Price (USD)	Street Price
1.		Sony A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	1,699	ebay.com
2.		Olympus E-M1	5/5	+ +	..	84/100	4.5/5	4.5/5	Sep 2013	1,399	ebay.com
3.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
4.		Olympus E-M1 II	5/5	+ +	5/5	85/100	4.5/5	4.5/5	Sep 2016	1,999	ebay.com
5.		Olympus E-M5	4/5	+ +	..	80/100	4.5/5	5/5	Feb 2012	1,299	ebay.com
6.		Olympus E-M5 II	5/5	+ +	4.5/5	81/100	5/5	5/5	Feb 2015	1,099	ebay.com
7.		Olympus E-P5	5/5	+ +	..	78/100	4.5/5	5/5	May 2013	999	ebay.com
8.		Olympus PEN-F	..	..	4/5	82/100	4.5/5	5/5	Jan 2016	1,199	ebay.com
9.		Panasonic GH4	5/5	+ +	..	85/100	5/5	5/5	Feb 2014	1,499	ebay.com
10.		Samsung NX1	5/5	..	..	87/100	5/5	5/5	Sep 2014	1,499	ebay.com
11.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	1,999	ebay.com
12.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	1,999	amazon.com
13.		Sony A7C	3.5/5	..	3.5/5	86/100	4/5	4/5	Sep 2020	1,799	amazon.com
14.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	2,299	ebay.com
15.		Sony A7S	4/5	..	..	86/100	4.5/5	5/5	Apr 2014	2,499	ebay.com
16.		Sony RX1	5/5	..	..	79/100	4/5	4.5/5	Sep 2012	2,799	ebay.com
17.		Sony RX1R	5/5	..	..	..	4/5	4.5/5	Jun 2013	2,799	ebay.com
Note: (+ +) 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. 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. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

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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 a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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