Nikon D3100 vs Olympus E-M10 III

The Nikon D3100 and the Olympus OM-D E-M10 Mark III are two digital cameras that were officially introduced, respectively, in August 2010 and August 2017. The D3100 is a DSLR, while the E-M10 III is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (D3100) and a Four Thirds (E-M10 III) sensor. The Nikon has a resolution of 14.2 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

Nikon D3100		Olympus E-M10 III
Digital single lens reflex		Mirrorless system camera
Nikon F mount lenses		Micro Four Thirds lenses
14.2 MP – APS-C sensor		15.9 MP – Four Thirds sensor
1080/24p Video		4K/30p Video
ISO 100-3,200 (100 - 12,800)		ISO 200-25,600
Optical viewfinder		Electronic viewfinder (2360k dots)
3.0" LCD – 230k dots		3.0" LCD – 1040k dots
Fixed screen (not touch-sensitive)		Tilting touchscreen
3 shutter flaps per second		8.6 shutter flaps per second
Lens stabilization only		In-body stabilization
550 shots per battery charge		330 shots per battery charge
124 x 96 x 75 mm, 505 g		122 x 84 x 50 mm, 410 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D3100 and the Olympus OM-D E-M10 Mark III? 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 Nikon D3100 and the Olympus E-M10 III 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 D3100 can be obtained in two different colors (black, red), while the E-M10 III is also available in two color-versions, but different ones (black, silver).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Olympus E-M10 III is notably smaller (14 percent) than the Nikon D3100. Moreover, the E-M10 III is markedly lighter (19 percent) than the D3100. In this context, it is worth noting that neither the D3100 nor the E-M10 III 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 Nikon Lens Catalog (D3100) and the Micro Four Thirds Lens Catalog (E-M10 III). Mirrorless cameras, such as the E-M10 III, have moreover the advantage that they can use many lenses from other systems via adapters, as they have a relatively short flange to focal plane distance.

Concerning battery life, the D3100 gets 550 shots out of its Nikon EN-EL14 battery, while the E-M10 III can take 330 images on a single charge of its Olympus BLS-50 power pack.

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.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	599	ebay.com
2.		Olympus E-M10 III	122 mm	84 mm	50 mm	410 g	330	n	Aug 2017	649	ebay.com
3.		Nikon D5600	124 mm	97 mm	70 mm	465 g	970	n	Nov 2016	699	ebay.com
4.		Nikon D3400	124 mm	98 mm	76 mm	445 g	1200	n	Aug 2016	499	ebay.com
5.		Nikon D3300	124 mm	98 mm	76 mm	430 g	700	n	Jan 2014	499	ebay.com
6.		Nikon D3200	125 mm	96 mm	77 mm	505 g	540	n	Apr 2012	599	ebay.com
7.		Nikon D5100	128 mm	97 mm	79 mm	560 g	660	n	Apr 2011	749	ebay.com
8.		Nikon D3000	126 mm	97 mm	64 mm	536 g	500	n	Jul 2009	599	ebay.com
9.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	749	ebay.com
10.		Nikon D60	126 mm	94 mm	64 mm	522 g	500	n	Jan 2008	629	ebay.com
11.		Nikon D40X	124 mm	94 mm	64 mm	522 g	520	n	Mar 2007	729	ebay.com
12.		Nikon D40	124 mm	94 mm	64 mm	522 g	470	n	Nov 2006	499	ebay.com
13.		Olympus E-M10 IV	122 mm	84 mm	49 mm	383 g	360	n	Aug 2020	699	amazon.com
14.		Olympus E-PL9	117 mm	68 mm	39 mm	380 g	350	n	Feb 2018	599	ebay.com
15.		Olympus E-PL8	115 mm	67 mm	38 mm	357 g	350	n	Sep 2016	549	ebay.com
16.		Olympus E-M10 II	120 mm	83 mm	47 mm	390 g	320	n	Aug 2015	649	ebay.com
17.		Olympus E-M10	119 mm	82 mm	46 mm	396 g	320	n	Jan 2014	699	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
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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 D3100 was somewhat cheaper (by 8 percent) than the E-M10 III at launch, but both cameras fall into the same price category. 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 Nikon D3100 features an APS-C sensor and the Olympus E-M10 III a Four Thirds sensor. The sensor area in the E-M10 III is 37 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 2.0. The sensor in the D3100 has a native 3:2 aspect ratio, while the one in the E-M10 III offers a 4:3 aspect.

Despite having a smaller sensor, the E-M10 III offers a higher resolution of 15.9 megapixels, compared with 14.2 MP of the D3100. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.76μm versus 5.01μm for the D3100). However, it should be noted that the E-M10 III is much more recent (by 7 years) than the D3100, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. Coming back to sensor resolution, it should be mentioned that the E-M10 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The Nikon D3100 has a native sensitivity range from ISO 100 to ISO 3200, which can be extended to ISO 100-12800. The corresponding ISO settings for the Olympus OM-D E-M10 Mark III 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.

For many cameras, data on sensor performance has been reported by DXO Mark. This service is based on lab testing and assigns an overall score to each camera sensor, as well as ratings for dynamic range ("DXO Landscape"), color depth ("DXO Portrait"), and low-light sensitivity ("DXO Sports"). The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

Sensor Characteristics

#		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Nikon D3100	APS-C	14.2	4608	3072	1080/24p	22.5	11.3	919	67
2.		Olympus E-M10 III	Four Thirds	15.9	4608	3456	4K/30p	23.1	12.8	1120	74
3.		Nikon D5600	APS-C	24.0	6000	4000	1080/60p	24.1	14.0	1306	84
4.		Nikon D3400	APS-C	24.0	6000	4000	1080/60p	24.8	13.9	1192	86
5.		Nikon D3300	APS-C	24.0	6000	4000	1080/60p	24.3	12.8	1385	82
6.		Nikon D3200	APS-C	24.1	6016	4000	1080/30p	24.1	13.2	1131	81
7.		Nikon D5100	APS-C	16.1	4928	3264	1080/30p	23.5	13.6	1183	80
8.		Nikon D3000	APS-C	10.0	3872	2592	none	22.3	11.1	563	62
9.		Nikon D5000	APS-C	12.2	4288	2848	720/24p	22.7	12.5	868	72
10.		Nikon D60	APS-C	10.0	3872	2592	none	22.5	11.4	562	65
11.		Nikon D40X	APS-C	10.0	3872	2592	none	22.4	11.4	516	63
12.		Nikon D40	APS-C	6.0	3008	2000	none	21.0	11.0	561	56
13.		Olympus E-M10 IV	Four Thirds	20.2	5184	3888	4K/30p	23.3	13.2	1402	76
14.		Olympus E-PL9	Four Thirds	15.9	4608	3456	4K/30p	23.1	12.8	1162	74
15.		Olympus E-PL8	Four Thirds	15.9	4608	3456	1080/30p	23.0	12.6	1030	73
16.		Olympus E-M10 II	Four Thirds	15.9	4608	3456	1080/60p	23.1	12.5	842	73
17.		Olympus E-M10	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.3	884	72
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. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the E-M10 III provides a better video resolution than the D3100. It can shoot movie footage at 4K/30p, while the Nikon is limited to 1080/24p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the E-M10 III has an electronic viewfinder (2360k dots), while the D3100 has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The viewfinder in the E-M10 III offers a wider field of view (100%) than the one in the D3100 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the E-M10 III has a higher magnification (0.62x vs 0.53x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The following table reports on some other key feature differences and similarities of the Nikon D3100, the Olympus E-M10 III, and comparable cameras.

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.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
2.		Olympus E-M10 III	2360	n	3.0 / 1040	tilting	Y	1/4000s	8.6/s	Y	Y
3.		Nikon D5600	optical	n	3.2 / 1037	swivel	Y	1/4000s	5.0/s	Y	n
4.		Nikon D3400	optical	n	3.0 / 921	fixed	n	1/4000s	5.0/s	Y	n
5.		Nikon D3300	optical	n	3.0 / 921	fixed	n	1/4000s	5.0/s	Y	n
6.		Nikon D3200	optical	n	3.0 / 921	fixed	n	1/4000s	4.0/s	Y	n
7.		Nikon D5100	optical	n	3.0 / 921	swivel	n	1/4000s	4.0/s	Y	n
8.		Nikon D3000	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
9.		Nikon D5000	optical	n	2.7 / 230	full-flex	n	1/4000s	4.0/s	Y	n
10.		Nikon D60	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
11.		Nikon D40X	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
12.		Nikon D40	optical	n	2.5 / 230	fixed	n	1/4000s	2.5/s	Y	n
13.		Olympus E-M10 IV	2360	n	3.0 / 1040	tilting	Y	1/4000s	15.0/s	Y	Y
14.		Olympus E-PL9	none	n	3.0 / 1040	tilting	Y	1/4000s	8.6/s	Y	Y
15.		Olympus E-PL8	optional	n	3.0 / 1037	tilting	Y	1/4000s	8.0/s	n	Y
16.		Olympus E-M10 II	2360	n	3.0 / 1040	tilting	Y	1/4000s	8.0/s	Y	Y
17.		Olympus E-M10	1440	n	3.0 / 1037	tilting	Y	1/4000s	8.0/s	Y	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-M10 III has a touchscreen, while the D3100 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-M10 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-M10 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.

Concerning the storage of imaging data, both the D3100 and the E-M10 III write their files to SDXC cards. The E-M10 III supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s), while the D3100 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 Nikon D3100 and Olympus OM-D E-M10 Mark III 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.		Nikon D3100	Y	mono / mono	-	-	mini	2.0	-	-	-
2.		Olympus E-M10 III	Y	stereo / mono	-	-	micro	2.0	Y	-	-
3.		Nikon D5600	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
4.		Nikon D3400	Y	mono / mono	-	-	mini	2.0	-	-	Y
5.		Nikon D3300	Y	mono / mono	Y	-	mini	2.0	-	-	-
6.		Nikon D3200	Y	mono / mono	Y	-	mini	2.0	-	-	-
7.		Nikon D5100	Y	mono / mono	Y	-	mini	2.0	-	-	-
8.		Nikon D3000	Y	- / -	-	-	-	2.0	-	-	-
9.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-
10.		Nikon D60	Y	- / -	-	-	-	2.0	-	-	-
11.		Nikon D40X	Y	- / -	-	-	-	2.0	-	-	-
12.		Nikon D40	Y	- / -	-	-	-	2.0	-	-	-
13.		Olympus E-M10 IV	Y	stereo / mono	-	-	micro	2.0	Y	-	Y
14.		Olympus E-PL9	Y	stereo / mono	-	-	micro	2.0	Y	-	Y
15.		Olympus E-PL8	Y	stereo / mono	-	-	micro	2.0	Y	-	-
16.		Olympus E-M10 II	Y	stereo / mono	-	-	micro	2.0	Y	-	-
17.		Olympus E-M10	Y	stereo / mono	-	-	micro	2.0	Y	-	-

It is notable that the E-M10 III offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the D3100 does not provide wifi capability.

Both the D3100 and the E-M10 III have been discontinued, but can regularly be found used on ebay. The D3100 was replaced by the Nikon D3200, while the E-M10 III was followed by the Olympus E-M10 IV. Further information on the features and operation of the D3100 and E-M10 III can be found, respectively, in the Nikon D3100 Manual (free pdf) or the online Olympus E-M10 III Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Nikon D3100 and the Olympus E-M10 III? Which camera is better? The listing below highlights the relative strengths of the two models.

Arguments in favor of the Nikon D3100:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Longer lasting: Can take more shots (550 versus 330) on a single battery charge.
• More heavily discounted: Has been available for much longer (launched in August 2010).

Reasons to prefer the Olympus OM-D E-M10 Mark III:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/24p).
• More framing info: Has an electronic viewfinder that displays shooting data.
• More complete view: Has a viewfinder with a larger field of view (100% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.62x vs 0.53x).
• More detailed LCD: Has a higher resolution rear screen (1040k vs 230k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• Faster burst: Shoots at higher frequency (8.6 vs 3 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 (122x84mm vs 124x96mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 95g or 19 percent) and is thus easier to take along.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Faster buffer clearing: Has an SD card interface that supports the UHS-II standard.
• More modern: Reflects 7 years of technical progress since the D3100 launch.

If the count of relative strengths (bullet points above) is taken as a measure, the E-M10 III is the clear winner of the contest (18 : 4 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 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 Nikon D3100 and the Olympus E-M10 III place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens Camera listings whether the two cameras rank among the cream of the crop.

In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it says little about, for example, the shooting experience and imaging performance of the D3100 and the E-M10 III in practical situations. 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 why hands-on reviews by experts are important. The adjacent summary-table relays the overall verdicts of several of the most popular 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.

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.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	599	ebay.com
2.		Olympus E-M10 III	..	+	5/5	80/100	4.5/5	4.5/5	Aug 2017	649	ebay.com
3.		Nikon D5600	4/5	..	4/5	79/100	4.5/5	4/5	Nov 2016	699	ebay.com
4.		Nikon D3400	4/5	+	4/5	76/100	4/5	4.5/5	Aug 2016	499	ebay.com
5.		Nikon D3300	3/5	+	..	77/100	4.5/5	4.5/5	Jan 2014	499	ebay.com
6.		Nikon D3200	5/5	+ +	..	73/100	4.5/5	4.5/5	Apr 2012	599	ebay.com
7.		Nikon D5100	5/5	+ +	..	76/100	4.5/5	4.5/5	Apr 2011	749	ebay.com
8.		Nikon D3000	..	+	..	72/100	4/5	4.5/5	Jul 2009	599	ebay.com
9.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	749	ebay.com
10.		Nikon D60	..	80/100	..	+ +	4/5	4.5/5	Jan 2008	629	ebay.com
11.		Nikon D40X	..	79/100	..	+ +	4/5	4/5	Mar 2007	729	ebay.com
12.		Nikon D40	..	81/100	..	+ +	o	4.5/5	Nov 2006	499	ebay.com
13.		Olympus E-M10 IV	4.5/5	..	5/5	81/100	4.5/5	4.5/5	Aug 2020	699	amazon.com
14.		Olympus E-PL9	..	+	..	..	4.5/5	4/5	Feb 2018	599	ebay.com
15.		Olympus E-PL8	..	..	..	..	4.5/5	4/5	Sep 2016	549	ebay.com
16.		Olympus E-M10 II	4.5/5	+ +	..	80/100	5/5	5/5	Aug 2015	649	ebay.com
17.		Olympus E-M10	4/5	..	..	80/100	5/5	5/5	Jan 2014	699	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 would like to check on the differences and similarities of other camera models, just use the search menu below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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