Sony A5100 vs Nikon D3100

The Sony Alpha A5100 and the Nikon D3100 are two digital cameras that were announced, respectively, in August 2014 and August 2010. The A5100 is a mirrorless interchangeable lens camera, while the D3100 is a DSLR. Both cameras are equipped with an APS-C sensor. The Sony has a resolution of 24 megapixels, whereas the Nikon provides 14.2 MP.

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

Headline Specifications

Sony A5100		Nikon D3100
Mirrorless system camera		Digital single lens reflex
Sony E mount lenses		Nikon F mount lenses
24 MP – APS-C sensor		14.2 MP – APS-C sensor
1080/60p Video		1080/24p Video
ISO 100-25,600		ISO 100-3,200 (100 - 12,800)
No viewfinder, LCD framing		Optical viewfinder
3.0" LCD – 922k dots		3.0" LCD – 230k dots
Tilting touchscreen		Fixed screen (not touch-sensitive)
6 shutter flaps per second		3 shutter flaps per second
400 shots per battery charge		550 shots per battery charge
110 x 63 x 36 mm, 283 g		124 x 96 x 75 mm, 505 g

Check A5100 offers at
ebay.com
Check D3100 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A5100 and the Nikon D3100? 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 Sony A5100 and the Nikon D3100 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 measures are rounded to the nearest millimeter.

The A5100 can be obtained in two different colors (black, white), while the D3100 is also available in two color-versions, but different ones (black, red).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Nikon D3100 is considerably larger (72 percent) than the Sony A5100. Moreover, the D3100 is substantially heavier (78 percent) than the A5100. In this context, it is worth noting that neither the A5100 nor the D3100 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. Both cameras have similarly sized sensors, but DSLRs have a larger flange-to-focal plane distance than mirrorless cameras, which imposes contraints on the optical engineering process and generally leads to bigger and heavier lenses. You can compare the optics available for the two cameras in the Sony E-Mount Lens Catalog (A5100) and the Nikon Lens Catalog (D3100). Mirrorless cameras, such as the Sony A5100, have moreover the advantage that they have a relatively short flange to focal plane distance and can thus use many lenses from other systems via adapters.

Concerning battery life, the A5100 gets 400 shots out of its Sony NP-FW50 battery, while the D3100 can take 550 images on a single charge of its Nikon EN-EL14 power pack. The power pack in the A5100 can be charged via the USB port, so that it is not always necessary to take the battery charger along when travelling.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.

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 A5100	110 mm	63 mm	36 mm	283 g	400	n	Aug 2014	549	ebay.com
2.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	599	ebay.com
3.		Nikon D3000	126 mm	97 mm	64 mm	536 g	500	n	Jul 2009	599	ebay.com
4.		Nikon D3200	125 mm	96 mm	77 mm	505 g	540	n	Apr 2012	599	ebay.com
5.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	749	ebay.com
6.		Nikon D5100	128 mm	97 mm	79 mm	560 g	660	n	Apr 2011	749	ebay.com
7.		Nikon D7000	132 mm	105 mm	77 mm	780 g	1050	Y	Sep 2010	1,499	ebay.com
8.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	329	ebay.com
9.		Sony A5000	110 mm	63 mm	36 mm	269 g	420	n	Jan 2014	449	ebay.com
10.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	599	ebay.com
11.		Sony NEX-3	117 mm	62 mm	33 mm	297 g	330	n	May 2010	599	ebay.com
12.		Sony NEX-3N	110 mm	62 mm	35 mm	269 g	480	n	Feb 2013	499	ebay.com
13.		Sony NEX-5T	111 mm	59 mm	39 mm	276 g	330	n	Aug 2013	699	ebay.com
14.		Sony NEX-F3	117 mm	67 mm	42 mm	314 g	470	n	May 2012	599	ebay.com
15.		Sony RX100	102 mm	58 mm	36 mm	240 g	330	n	Jun 2012	649	ebay.com
16.		Sony RX100 II	102 mm	58 mm	38 mm	281 g	350	n	Jun 2013	749	ebay.com
17.		Sony RX100 IV	102 mm	58 mm	41 mm	298 g	280	n	Jun 2015	999	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

The price is, of course, an important factor in any camera decision. The retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. The A5100 was somewhat cheaper (by 8 percent) than the D3100 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 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. 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 associated with larger, more expensive camera bodies and lenses.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the D3100 is 3 percent smaller. They nevertheless have the same format factor of 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 24MP, the A5100 offers a higher resolution than the D3100 (14.2MP), but the A5100 has smaller individual pixels (pixel pitch of 3.91μm versus 5.01μm for the D3100). However, the A5100 is a much more recent model (by 4 years) than the D3100, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels.

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 Nikon D3100 are 23 x 15.4 inches or 58.5 x 39 cm for good quality, 18.4 x 12.3 inches or 46.8 x 31.2 cm for very good quality, and 15.4 x 10.2 inches or 39 x 26 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 Sony Alpha A5100 has a native sensitivity range from ISO 100 to ISO 25600. The corresponding ISO settings for the Nikon D3100 are ISO 100 to ISO 3200, with the possibility to increase the ISO range to 100-12800.

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. Of the two cameras under review, the A5100 provides substantially higher image quality than the D3100, with an overall score that is 13 points higher. This advantage is based on 1.3 bits higher color depth, 1.4 EV in additional dynamic range, and 0.6 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 A5100	APS-C	24.0	6000	4000	1080/60p	23.8	12.7	1347	80
2.		Nikon D3100	APS-C	14.2	4608	3072	1080/24p	22.5	11.3	919	67
3.		Nikon D3000	APS-C	10.0	3872	2592	none	22.3	11.1	563	62
4.		Nikon D3200	APS-C	24.1	6016	4000	1080/30p	24.1	13.2	1131	81
5.		Nikon D5000	APS-C	12.2	4288	2848	720/24p	22.7	12.5	868	72
6.		Nikon D5100	APS-C	16.1	4928	3264	1080/30p	23.5	13.6	1183	80
7.		Nikon D7000	APS-C	16.1	4928	3264	1080/24p	23.5	13.9	1167	80
8.		Sony A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
9.		Sony A5000	APS-C	19.8	5456	3632	1080/60i	23.8	13.0	1089	79
10.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
11.		Sony NEX-3	APS-C	14.0	4592	3056	720/30p	22.1	12.0	830	68
12.		Sony NEX-3N	APS-C	16.0	4912	3264	1080/60i	22.8	12.5	1067	74
13.		Sony NEX-5T	APS-C	16.0	4912	3264	1080/60p	23.6	13.0	1015	78
14.		Sony NEX-F3	APS-C	16.0	4912	3264	1080/60i	22.7	12.3	1114	73
15.		Sony RX100	1-inch	20.0	5472	3648	1080/60p	22.6	12.4	390	66
16.		Sony RX100 II	1-inch	20.0	5472	3648	1080/60p	22.5	12.4	483	67
17.		Sony RX100 IV	1-inch	20.0	5472	3648	4K/30p	22.8	12.6	591	70

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A5100 provides a higher frame rate than the D3100. It can shoot video footage at 1080/60p, while the Nikon is limited to 1080/24p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the D3100 has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the A5100 relies on live view and the rear LCD for framing. The table below summarizes some of the other core capabilities of the Sony A5100 and Nikon D3100 in connection with corresponding information for a sample of similar 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.		Sony A5100	none	n	3.0 / 922	tilting	Y	1/4000s	6.0/s	Y	n
2.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
3.		Nikon D3000	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
4.		Nikon D3200	optical	n	3.0 / 921	fixed	n	1/4000s	4.0/s	Y	n
5.		Nikon D5000	optical	n	2.7 / 230	full-flex	n	1/4000s	4.0/s	Y	n
6.		Nikon D5100	optical	n	3.0 / 921	swivel	n	1/4000s	4.0/s	Y	n
7.		Nikon D7000	optical	Y	3.0 / 921	fixed	n	1/8000s	6.0/s	Y	n
8.		Sony A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
9.		Sony A5000	none	n	3.0 / 461	tilting	n	1/4000s	3.5/s	Y	n
10.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
11.		Sony NEX-3	optional	n	3.0 / 920	tilting	n	1/4000s	7.0/s	n	n
12.		Sony NEX-3N	optional	n	3.0 / 460	tilting	n	1/4000s	4.0/s	Y	n
13.		Sony NEX-5T	optional	n	3.0 / 922	tilting	Y	1/4000s	10.0/s	n	n
14.		Sony NEX-F3	optional	n	3.0 / 920	tilting	n	1/4000s	5.5/s	Y	n
15.		Sony RX100	none	n	3.0 / 1229	fixed	n	1/2000s	10.0/s	Y	Y
16.		Sony RX100 II	optional	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
17.		Sony RX100 IV	2359	n	3.0 / 1228	tilting	n	1/2000s	16.0/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 A5100 has a touchscreen, while the D3100 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

The A5100 writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the D3100 uses SDXC cards. The A5100 supports UHS-I cards (Ultra High Speed data transfer of up to 104 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 Sony Alpha A5100 and Nikon D3100 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 A5100	-	stereo / mono	-	-	micro	2.0	Y	Y	-
2.		Nikon D3100	Y	mono / mono	-	-	mini	2.0	-	-	-
3.		Nikon D3000	Y	- / -	-	-	-	2.0	-	-	-
4.		Nikon D3200	Y	mono / mono	Y	-	mini	2.0	-	-	-
5.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-
6.		Nikon D5100	Y	mono / mono	Y	-	mini	2.0	-	-	-
7.		Nikon D7000	Y	mono / mono	Y	-	mini	2.0	-	-	-
8.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Sony A5000	-	stereo / mono	-	-	micro	2.0	Y	Y	-
10.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
11.		Sony NEX-3	Y	stereo / mono	-	-	mini	2.0	-	-	-
12.		Sony NEX-3N	-	stereo / mono	-	-	micro	2.0	-	-	-
13.		Sony NEX-5T	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
14.		Sony NEX-F3	Y	stereo / mono	-	-	mini	2.0	-	-	-
15.		Sony RX100	-	stereo / mono	-	-	micro	2.0	-	-	-
16.		Sony RX100 II	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
17.		Sony RX100 IV	-	stereo / mono	-	-	micro	2.0	Y	Y	-

It is notable that the A5100 offers wifi support, while the D3100 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Both the A5100 and the D3100 have been discontinued, but can regularly be found used on ebay. The D3100 was replaced by the Nikon D3200, while the A5100 does not have a direct successor. Further information on the features and operation of the A5100 and D3100 can be found, respectively, in the Sony A5100 Manual (free pdf) or the online Nikon D3100 Manual.

Review summary

So what conclusions can be drawn? Is the Sony A5100 better than the Nikon D3100 or vice versa? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Sony Alpha A5100:

• More detail: Offers more megapixels (24 vs 14.2MP) with a 30% higher linear resolution.
• Better image quality: Scores substantially higher (13 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (1.3 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (1.4 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (0.6 stops ISO advantage).
• Better video: Provides higher movie framerates (1080/60p versus 1080/24p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• More detailed LCD: Has a higher resolution rear screen (922k vs 230k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster burst: Shoots at higher frequency (6 vs 3 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (110x63mm vs 124x96mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 222g or 44 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.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Reflects 4 years of technical progress since the D3100 launch.

Advantages of the Nikon D3100:

• Easier framing: Has an optical viewfinder for image composition and settings control.
• Longer lasting: Gets more shots (550 versus 400) out of a single battery charge.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• More heavily discounted: Has been around for much longer (launched in August 2010).

If the count of individual advantages (bullet points above) is taken as a guide, the A5100 is the clear winner of the match-up (20 : 4 points). However, the relevance of individual strengths will vary across photographers, so that you might want to apply your own weighing scheme to the summary points when reflecting and deciding 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 Sony A5100 and the Nikon D3100 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 the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the A5100 or the D3100. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.

Expert reviews

This is why hands-on reviews by experts are important. The following table reports the overall ratings of the cameras as published by some of the major camera review sites (amateurphotographer [AP], cameralabs [CL], digitalcameraworld [DCW], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.

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 A5100	4.5/5	+	..	..	4.5/5	5/5	Aug 2014	549	ebay.com
2.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	599	ebay.com
3.		Nikon D3000	..	+	..	72/100	4/5	4.5/5	Jul 2009	599	ebay.com
4.		Nikon D3200	5/5	+ +	..	73/100	4.5/5	4.5/5	Apr 2012	599	ebay.com
5.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	749	ebay.com
6.		Nikon D5100	5/5	+ +	..	76/100	4.5/5	4.5/5	Apr 2011	749	ebay.com
7.		Nikon D7000	4/5	..	..	80/100	4.5/5	4.5/5	Sep 2010	1,499	ebay.com
8.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	329	ebay.com
9.		Sony A5000	3/5	+	..	..	4.5/5	4.5/5	Jan 2014	449	ebay.com
10.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	599	ebay.com
11.		Sony NEX-3	..	..	..	70/100	4.5/5	4/5	May 2010	599	ebay.com
12.		Sony NEX-3N	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	499	ebay.com
13.		Sony NEX-5T	..	..	..	..	4.5/5	4.5/5	Aug 2013	699	ebay.com
14.		Sony NEX-F3	4/5	..	..	74/100	4.5/5	4.5/5	May 2012	599	ebay.com
15.		Sony RX100	5/5	+ +	..	78/100	4/5	5/5	Jun 2012	649	ebay.com
16.		Sony RX100 II	5/5	+ +	..	79/100	4.5/5	4.5/5	Jun 2013	749	ebay.com
17.		Sony RX100 IV	4.5/5	+ +	..	85/100	4/5	4.5/5	Jun 2015	999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Check A5100 offers at
ebay.com
Check D3100 offers at
ebay.com

Other camera comparisons

Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes 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.

~

Check A5100 offers at
ebay.com
Check D3100 offers at
ebay.com

Did you notice an error on this page? If so, please get in touch, so that we can correct the information.