Olympus E-M10 II vs Sony A5100

The Olympus OM-D E-M10 Mark II and the Sony Alpha A5100 are two digital cameras that were revealed to the public, respectively, in August 2015 and August 2014. Both the E-M10 II and the A5100 are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M10 II) and an APS-C (A5100) sensor. The Olympus has a resolution of 15.9 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.

Headline Specifications

Olympus E-M10 II		Sony A5100
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Sony E mount lenses
15.9 MP – Four Thirds sensor		24 MP – APS-C sensor
1080/60p Video		1080/60p Video
ISO 200-25,600		ISO 100-25,600
Electronic viewfinder (2360k dots)		No viewfinder, LCD framing
3.0" LCD – 1040k dots		3.0" LCD – 922k dots
Tilting touchscreen		Tilting touchscreen
8 shutter flaps per second		6 shutter flaps per second
In-body stabilization		Lens stabilization only
320 shots per battery charge		400 shots per battery charge
120 x 83 x 47 mm, 390 g		110 x 63 x 36 mm, 283 g

Check E-M10 II offers at
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Check A5100 offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus OM-D E-M10 Mark II and the Sony Alpha A5100? 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

The physical size and weight of the Olympus E-M10 II and the Sony A5100 are illustrated 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-M10 II can be obtained in three different colors (black, silver, brown), while the A5100 is available in two color-versions (black, white).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A5100 is considerably smaller (30 percent) than the Olympus E-M10 II. Moreover, the A5100 is markedly lighter (27 percent) than the E-M10 II. In this context, it is worth noting that neither the E-M10 II nor the A5100 are weather-sealed.

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 Micro Four Thirds Lens Catalog (E-M10 II) and the Sony E-Mount Lens Catalog (A5100). 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-M10 II gets 320 shots out of its Olympus BLS-50 battery, while the A5100 can take 400 images on a single charge of its Sony NP-FW50 power pack. The power pack in the A5100 can be charged via the USB port, which can be very convenient when travelling.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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.		Olympus E-M10 II	120 mm	83 mm	47 mm	390 g	320	n	Aug 2015	649	ebay.com
2.		Sony A5100	110 mm	63 mm	36 mm	283 g	400	n	Aug 2014	549	ebay.com
3.		Olympus E-M10	119 mm	82 mm	46 mm	396 g	320	n	Jan 2014	699	ebay.com
4.		Olympus E-M10 III	122 mm	84 mm	50 mm	410 g	330	n	Aug 2017	649	ebay.com
5.		Olympus E-P5	122 mm	69 mm	37 mm	420 g	330	n	May 2013	999	ebay.com
6.		Olympus E-PL5	111 mm	64 mm	38 mm	325 g	360	n	Sep 2012	599	ebay.com
7.		Olympus E-PL6	111 mm	64 mm	38 mm	325 g	360	n	May 2013	599	ebay.com
8.		Olympus E-PL7	115 mm	67 mm	38 mm	357 g	350	n	Aug 2014	599	ebay.com
9.		Olympus E-PL8	115 mm	67 mm	38 mm	357 g	350	n	Sep 2016	549	ebay.com
10.		Olympus E-PL9	117 mm	68 mm	39 mm	380 g	350	n	Feb 2018	599	ebay.com
11.		Olympus PEN-F	125 mm	72 mm	37 mm	427 g	330	n	Jan 2016	1,199	ebay.com
12.		Panasonic GX85	122 mm	71 mm	44 mm	426 g	290	n	Apr 2016	799	amazon.com
13.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	329	ebay.com
14.		Sony A5000	110 mm	63 mm	36 mm	269 g	420	n	Jan 2014	449	ebay.com
15.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	599	ebay.com
16.		Sony NEX-3	117 mm	62 mm	33 mm	297 g	330	n	May 2010	599	ebay.com
17.		Sony NEX-3N	110 mm	62 mm	35 mm	269 g	480	n	Feb 2013	499	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 A5100 was launched at a somewhat lower price (by 15 percent) than the E-M10 II, 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 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 tend to be associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Olympus E-M10 II features a Four Thirds sensor and the Sony A5100 an APS-C sensor. The sensor area in the A5100 is 63 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.5. The sensor in the E-M10 II has a native 4:3 aspect ratio, while the one in the A5100 offers a 3:2 aspect.

With 24MP, the A5100 offers a higher resolution than the E-M10 II (15.9MP), but the A5100 nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 3.76μm for the E-M10 II) due to its larger sensor. However, the E-M10 II is a somewhat more recent model (by 1 year) than the A5100, and its sensor might 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-M10 II has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Sony A5100 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A5100 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-M10 II 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 A5100 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Olympus OM-D E-M10 Mark II 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 Sony Alpha A5100 are ISO 100 to ISO 25600 (no boost).

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 consideration, the A5100 has a markedly higher DXO score than the E-M10 II (overall score 7 points higher), which will translate into better image quality. The advantage is based on 0.7 bits higher color depth, 0.2 EV in additional dynamic range, and 0.7 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.		Olympus E-M10 II	Four Thirds	15.9	4608	3456	1080/60p	23.1	12.5	842	73
2.		Sony A5100	APS-C	24.0	6000	4000	1080/60p	23.8	12.7	1347	80
3.		Olympus E-M10	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.3	884	72
4.		Olympus E-M10 III	Four Thirds	15.9	4608	3456	4K/30p	23.1	12.8	1120	74
5.		Olympus E-P5	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.4	895	72
6.		Olympus E-PL5	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.3	889	72
7.		Olympus E-PL6	Four Thirds	15.9	4608	3456	1080/30p	22.5	12.0	717	68
8.		Olympus E-PL7	Four Thirds	15.9	4608	3456	1080/30p	22.7	12.4	873	72
9.		Olympus E-PL8	Four Thirds	15.9	4608	3456	1080/30p	23.0	12.6	1030	73
10.		Olympus E-PL9	Four Thirds	15.9	4608	3456	4K/30p	23.1	12.8	1162	74
11.		Olympus PEN-F	Four Thirds	20.2	5184	3888	1080/60p	23.1	12.4	894	74
12.		Panasonic GX85	Four Thirds	15.8	4592	3448	4K/30p	22.9	12.6	662	71
13.		Sony A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
14.		Sony A5000	APS-C	19.8	5456	3632	1080/60i	23.8	13.0	1089	79
15.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
16.		Sony NEX-3	APS-C	14.0	4592	3056	720/30p	22.1	12.0	830	68
17.		Sony NEX-3N	APS-C	16.0	4912	3264	1080/60i	22.8	12.5	1067	74
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, and both provide the same movie specifications (1080/60p).

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the E-M10 II has an electronic viewfinder (2360k dots), which can be very helpful when shooting in bright sunlight. In contrast, the A5100 relies on live view and the rear LCD for framing. The adjacent table lists some of the other core features of the Olympus E-M10 II and Sony A5100 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.		Olympus E-M10 II	2360	n	3.0 / 1040	tilting	Y	1/4000s	8.0/s	Y	Y
2.		Sony A5100	none	n	3.0 / 922	tilting	Y	1/4000s	6.0/s	Y	n
3.		Olympus E-M10	1440	n	3.0 / 1037	tilting	Y	1/4000s	8.0/s	Y	Y
4.		Olympus E-M10 III	2360	n	3.0 / 1040	tilting	Y	1/4000s	8.6/s	Y	Y
5.		Olympus E-P5	optional	n	3.0 / 1037	tilting	Y	1/8000s	9.0/s	Y	Y
6.		Olympus E-PL5	optional	n	3.0 / 460	tilting	Y	1/4000s	8.0/s	n	Y
7.		Olympus E-PL6	optional	n	3.0 / 460	tilting	Y	1/4000s	8.0/s	n	Y
8.		Olympus E-PL7	optional	n	3.0 / 1037	tilting	Y	1/4000s	8.0/s	n	Y
9.		Olympus E-PL8	optional	n	3.0 / 1037	tilting	Y	1/4000s	8.0/s	n	Y
10.		Olympus E-PL9	none	n	3.0 / 1040	tilting	Y	1/4000s	8.6/s	Y	Y
11.		Olympus PEN-F	2360	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
12.		Panasonic GX85	2765	n	3.0 / 1040	tilting	Y	1/4000s	8.0/s	Y	Y
13.		Sony A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
14.		Sony A5000	none	n	3.0 / 461	tilting	n	1/4000s	3.5/s	Y	n
15.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
16.		Sony NEX-3	optional	n	3.0 / 920	tilting	n	1/4000s	7.0/s	n	n
17.		Sony NEX-3N	optional	n	3.0 / 460	tilting	n	1/4000s	4.0/s	Y	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the E-M10 II and the A5100 is in-body image stabilization (IBIS). The E-M10 II reduces the risk of handshake-induced blur with all attached lenses, while the A5100 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-M10 II 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-M10 II 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-M10 II writes its imaging data to SDXC cards, while the A5100 uses SDXC or Memory Stick PRO Duo 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 Olympus OM-D E-M10 Mark II and Sony Alpha A5100 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.		Olympus E-M10 II	Y	stereo / mono	-	-	micro	2.0	Y	-	-
2.		Sony A5100	-	stereo / mono	-	-	micro	2.0	Y	Y	-
3.		Olympus E-M10	Y	stereo / mono	-	-	micro	2.0	Y	-	-
4.		Olympus E-M10 III	Y	stereo / mono	-	-	micro	2.0	Y	-	-
5.		Olympus E-P5	Y	stereo / mono	-	-	micro	2.0	Y	-	-
6.		Olympus E-PL5	Y	stereo / mono	-	-	mini	2.0	-	-	-
7.		Olympus E-PL6	Y	stereo / mono	-	-	mini	2.0	-	-	-
8.		Olympus E-PL7	Y	stereo / mono	-	-	micro	2.0	Y	-	-
9.		Olympus E-PL8	Y	stereo / mono	-	-	micro	2.0	Y	-	-
10.		Olympus E-PL9	Y	stereo / mono	-	-	micro	2.0	Y	-	Y
11.		Olympus PEN-F	Y	stereo / mono	-	-	micro	2.0	Y	-	-
12.		Panasonic GX85	Y	stereo / mono	-	-	micro	2.0	Y	-	-
13.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
14.		Sony A5000	-	stereo / mono	-	-	micro	2.0	Y	Y	-
15.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
16.		Sony NEX-3	Y	stereo / mono	-	-	mini	2.0	-	-	-
17.		Sony NEX-3N	-	stereo / mono	-	-	micro	2.0	-	-	-

It is notable that the E-M10 II has a hotshoe, while the A5100 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.

Both the E-M10 II and the A5100 have been discontinued, but can regularly be found used on ebay. The E-M10 II was replaced by the Olympus E-M10 III, while the A5100 does not have a direct successor. Further information on the features and operation of the E-M10 II and A5100 can be found, respectively, in the Olympus E-M10 II Manual (free pdf) or the online Sony A5100 Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Olympus E-M10 II and the Sony A5100? Which camera is better? The listing below highlights the relative strengths of the two models.

Arguments in favor of the Olympus OM-D E-M10 Mark II:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Easier framing: Has an electronic viewfinder for image composition and settings control.
• More detailed LCD: Has a higher resolution rear screen (1040k vs 922k dots).
• Faster burst: Shoots at higher frequency (8 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.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• More modern: Is somewhat more recent (announced 1 year after the A5100).

Advantages of the Sony Alpha A5100:

• More detail: Has more megapixels (24 vs 15.9MP), which boosts linear resolution by 25%.
• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better image quality: Scores markedly higher (7 points) in the DXO overall evaluation.
• Better low-light sensitivity: Can shoot in dim conditions (0.7 stops ISO advantage).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• More compact: Is smaller (110x63mm vs 120x83mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 107g or 27 percent) and is thus easier to take along.
• Longer lasting: Gets more shots (400 versus 320) out of a single battery charge.
• Easier travel charging: Can be conveniently charged via its USB port.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More affordable: Was released into a lower priced segment (15 percent cheaper at launch).
• More heavily discounted: Has been on the market for longer (launched in August 2014).

If the count of relative strengths (bullet points above) is taken as a measure, the A5100 is the clear winner of the contest (13 : 9 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-M10 II and the Sony A5100 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-M10 II or the A5100 perform in practice. 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 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.		Olympus E-M10 II	4.5/5	+ +	..	80/100	5/5	5/5	Aug 2015	649	ebay.com
2.		Sony A5100	4.5/5	+	..	..	4.5/5	5/5	Aug 2014	549	ebay.com
3.		Olympus E-M10	4/5	..	..	80/100	5/5	5/5	Jan 2014	699	ebay.com
4.		Olympus E-M10 III	..	+	5/5	80/100	4.5/5	4.5/5	Aug 2017	649	ebay.com
5.		Olympus E-P5	5/5	+ +	..	78/100	4.5/5	5/5	May 2013	999	ebay.com
6.		Olympus E-PL5	3/5	+ +	..	..	4.5/5	4.5/5	Sep 2012	599	ebay.com
7.		Olympus E-PL6	..	..	..	..	..	..	May 2013	599	ebay.com
8.		Olympus E-PL7	4/5	+	..	..	5/5	4/5	Aug 2014	599	ebay.com
9.		Olympus E-PL8	..	..	..	..	4.5/5	4/5	Sep 2016	549	ebay.com
10.		Olympus E-PL9	..	+	..	..	4.5/5	4/5	Feb 2018	599	ebay.com
11.		Olympus PEN-F	..	..	4/5	82/100	4.5/5	5/5	Jan 2016	1,199	ebay.com
12.		Panasonic GX85	4.5/5	+ +	..	82/100	5/5	5/5	Apr 2016	799	amazon.com
13.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	329	ebay.com
14.		Sony A5000	3/5	+	..	..	4.5/5	4.5/5	Jan 2014	449	ebay.com
15.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	599	ebay.com
16.		Sony NEX-3	..	..	..	70/100	4.5/5	4/5	May 2010	599	ebay.com
17.		Sony NEX-3N	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	499	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

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Other camera comparisons

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