Nikon D3100 vs Sony A3000

The Nikon D3100 and the Sony Alpha A3000 are two digital cameras that were announced, respectively, in August 2010 and August 2013. The D3100 is a DSLR, while the A3000 is a mirrorless interchangeable lens camera. Both cameras are equipped with an APS-C sensor. The Nikon has a resolution of 14.2 megapixels, whereas the Sony provides 19.8 MP.

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

Headline Specifications

Nikon D3100		Sony A3000
Digital single lens reflex		Mirrorless system camera
Nikon F mount lenses		Sony E mount lenses
14.2 MP – APS-C sensor		19.8 MP – APS-C sensor
1080/24p Video		1080/60i Video
ISO 100-3,200 (100 - 12,800)		ISO 100-16,000
Optical viewfinder		Electronic viewfinder (202k dots)
3.0" LCD – 230k dots		3.0" LCD – 230k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
3 shutter flaps per second		2.5 shutter flaps per second
550 shots per battery charge		470 shots per battery charge
124 x 96 x 75 mm, 505 g		128 x 91 x 85 mm, 411 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D3100 and the Sony Alpha A3000? 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 Sony A3000 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.

The D3100 can be obtained in two different colors (black, red), while the A3000 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 Sony A3000 is somewhat smaller (2 percent) than the Nikon D3100. Moreover, the A3000 is markedly lighter (19 percent) than the D3100. In this context, it is worth noting that neither the D3100 nor the A3000 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 Nikon Lens Catalog (D3100) and the Sony E-Mount Lens Catalog (A3000). Mirrorless cameras, such as the A3000, 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 A3000 can take 470 images on a single charge of its Sony NP-FW50 power pack. The power pack in the A3000 can be charged via the USB port, which can be very convenient 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.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price	Street Price
1.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	US$ 599	ebay.com
2.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	US$ 329	ebay.com
3.		Nikon D40	124 mm	94 mm	64 mm	522 g	470	n	Nov 2006	US$ 499	ebay.com
4.		Nikon D40X	124 mm	94 mm	64 mm	522 g	520	n	Mar 2007	US$ 729	ebay.com
5.		Nikon D60	126 mm	94 mm	64 mm	522 g	500	n	Jan 2008	US$ 629	ebay.com
6.		Nikon D3000	126 mm	97 mm	64 mm	536 g	500	n	Jul 2009	US$ 599	ebay.com
7.		Nikon D3200	125 mm	96 mm	77 mm	505 g	540	n	Apr 2012	US$ 599	ebay.com
8.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	US$ 749	ebay.com
9.		Nikon D5100	128 mm	97 mm	79 mm	560 g	660	n	Apr 2011	US$ 749	ebay.com
10.		Nikon D7000	132 mm	105 mm	77 mm	780 g	1050	Y	Sep 2010	US$ 1 499	ebay.com
11.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	US$ 599	ebay.com
12.		Sony A6400	120 mm	67 mm	50 mm	403 g	410	Y	Jan 2019	US$ 899	amazon.com
13.		Sony NEX-5N	111 mm	59 mm	38 mm	269 g	460	n	Aug 2011	US$ 699	ebay.com
14.		Sony NEX-6	120 mm	67 mm	43 mm	345 g	360	n	Sep 2012	US$ 999	ebay.com
15.		Sony NEX-7	120 mm	67 mm	43 mm	400 g	430	n	Aug 2011	US$ 1 349	ebay.com
16.		Sony NEX-C3	110 mm	60 mm	33 mm	225 g	400	n	Jun 2011	US$ 599	ebay.com
17.		Sony RX1R	113 mm	65 mm	70 mm	482 g	270	n	Jun 2013	US$ 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 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 A3000 was launched at a markedly lower price (by 45 percent) than the D3100, 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 size of the sensor inside a digital camera is one of the key determinants 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. 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. 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 19.8MP, the A3000 offers a higher resolution than the D3100 (14.2MP), but the A3000 has smaller individual pixels (pixel pitch of 4.25μm versus 5.01μm for the D3100). Yet, the A3000 is a much more recent model (by 3 years) than the D3100, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units.

The resolution advantage of the Sony A3000 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A3000 for good quality output (200 dots per inch) amounts to 27.3 x 18.2 inches or 69.3 x 46.1 cm, for very good quality (250 dpi) 21.8 x 14.5 inches or 55.4 x 36.9 cm, and for excellent quality (300 dpi) 18.2 x 12.1 inches or 46.2 x 30.8 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 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 Sony Alpha A3000 are ISO 100 to ISO 16000 (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.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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"). Of the two cameras under consideration, the A3000 offers substantially better image quality than the D3100 (overall score 11 points higher). The advantage is based on 1.2 bits higher color depth, 1.5 EV in additional dynamic range, and 0.2 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.		Nikon D3100	APS-C	14.2	4608	3072	1080/24p	22.5	11.3	919	67
2.		Sony A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
3.		Nikon D40	APS-C	6.0	3008	2000	none	21.0	11.0	561	56
4.		Nikon D40X	APS-C	10.0	3872	2592	none	22.4	11.4	516	63
5.		Nikon D60	APS-C	10.0	3872	2592	none	22.5	11.4	562	65
6.		Nikon D3000	APS-C	10.0	3872	2592	none	22.3	11.1	563	62
7.		Nikon D3200	APS-C	24.1	6016	4000	1080/30p	24.1	13.2	1131	81
8.		Nikon D5000	APS-C	12.2	4288	2848	720/24p	22.7	12.5	868	72
9.		Nikon D5100	APS-C	16.1	4928	3264	1080/30p	23.5	13.6	1183	80
10.		Nikon D7000	APS-C	16.1	4928	3264	1080/24p	23.5	13.9	1167	80
11.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
12.		Sony A6400	APS-C	24.0	6000	4000	4K/30p	24.0	13.6	1431	83
13.		Sony NEX-5N	APS-C	16.0	4912	3264	1080/60i	23.6	12.7	1079	77
14.		Sony NEX-6	APS-C	16.0	4912	3264	1080/60i	23.7	13.1	1018	78
15.		Sony NEX-7	APS-C	24.0	6000	4000	1080/60i	24.1	13.4	1016	81
16.		Sony NEX-C3	APS-C	16.0	4912	3264	720/30p	22.7	12.2	1083	73
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. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A3000 provides a faster frame rate than the D3100. It can shoot movie footage at 1080/60i, 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 A3000 has an electronic viewfinder (202k 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 A3000 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. On the other hand, the viewfinder of the D3100 has a higher magnification (0.53x vs 0.47x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Nikon D3100 and Sony A3000 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.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
2.		Sony A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
3.		Nikon D40	optical	n	2.5 / 230	fixed	n	1/4000s	2.5/s	Y	n
4.		Nikon D40X	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
5.		Nikon D60	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
6.		Nikon D3000	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
7.		Nikon D3200	optical	n	3.0 / 921	fixed	n	1/4000s	4.0/s	Y	n
8.		Nikon D5000	optical	n	2.7 / 230	full-flex	n	1/4000s	4.0/s	Y	n
9.		Nikon D5100	optical	n	3.0 / 921	swivel	n	1/4000s	4.0/s	Y	n
10.		Nikon D7000	optical	Y	3.0 / 921	fixed	n	1/8000s	6.0/s	Y	n
11.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
12.		Sony A6400	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	Y	n
13.		Sony NEX-5N	optional	n	3.0 / 920	tilting	Y	1/4000s	10.0/s	n	n
14.		Sony NEX-6	2359	n	3.0 / 921	tilting	n	1/4000s	10.0/s	Y	n
15.		Sony NEX-7	2359	n	3.0 / 921	tilting	n	1/4000s	10.0/s	Y	n
16.		Sony NEX-C3	optional	n	3.0 / 920	tilting	n	1/4000s	5.5/s	n	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.

The D3100 writes its imaging data to SDXC cards, while the A3000 uses SDXC or Memory Stick PRO Duo 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 Sony Alpha A3000 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.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
3.		Nikon D40	Y	- / -	-	-	-	2.0	-	-	-
4.		Nikon D40X	Y	- / -	-	-	-	2.0	-	-	-
5.		Nikon D60	Y	- / -	-	-	-	2.0	-	-	-
6.		Nikon D3000	Y	- / -	-	-	-	2.0	-	-	-
7.		Nikon D3200	Y	mono / mono	Y	-	mini	2.0	-	-	-
8.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-
9.		Nikon D5100	Y	mono / mono	Y	-	mini	2.0	-	-	-
10.		Nikon D7000	Y	mono / mono	Y	-	mini	2.0	-	-	-
11.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
12.		Sony A6400	Y	stereo / mono	Y	-	micro	2.0	Y	Y	Y
13.		Sony NEX-5N	Y	stereo / mono	-	-	mini	2.0	-	-	-
14.		Sony NEX-6	Y	stereo / mono	-	-	mini	2.0	Y	-	-
15.		Sony NEX-7	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Sony NEX-C3	Y	stereo / mono	-	-	mini	2.0	-	-	-
17.		Sony RX1R	Y	stereo / mono	Y	-	mini	2.0	-	-	-

Both the D3100 and the A3000 have been discontinued, but can regularly be found used on ebay. The D3100 was replaced by the Nikon D3200, while the A3000 does not have a direct successor. Further information on the features and operation of the D3100 and A3000 can be found, respectively, in the Nikon D3100 Manual (free pdf) or the online Sony A3000 Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Nikon D3100 and the Sony A3000? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Nikon D3100:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.53x vs 0.47x).
• Faster burst: Shoots at higher frequency (3 vs 2.5 flaps/sec) to capture the decisive moment.
• Longer lasting: Can take more shots (550 versus 470) on a single battery charge.
• More heavily discounted: Has been available for much longer (launched in August 2010).

Arguments in favor of the Sony Alpha A3000:

• More detail: Has more megapixels (19.8 vs 14.2MP), which boosts linear resolution by 18%.
• Better image quality: Scores substantially higher (11 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (1.2 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1.5 EV of extra DR).
• Better video: Provides higher movie framerates (1080/60i versus 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%).
• Less heavy: Has a lower weight (by 94g or 19 percent) and is thus easier to take along.
• Easier travel charging: Can be conveniently charged via its USB port.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• More affordable: Was introduced into a lower priced category (45 percent cheaper at launch).
• More modern: Reflects 3 years of technical progress since the D3100 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the A3000 is the clear winner of the contest (12 : 5 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 Nikon D3100 and the Sony A3000 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 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 D3100 or the A3000. 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 why hands-on reviews by experts are important. 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	Street Price
1.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	US$ 599	ebay.com
2.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	US$ 329	ebay.com
3.		Nikon D40	..	81/100	..	+ +	o	4.5/5	Nov 2006	US$ 499	ebay.com
4.		Nikon D40X	..	79/100	..	+ +	4/5	4/5	Mar 2007	US$ 729	ebay.com
5.		Nikon D60	..	80/100	..	+ +	4/5	4.5/5	Jan 2008	US$ 629	ebay.com
6.		Nikon D3000	..	+	..	72/100	4/5	4.5/5	Jul 2009	US$ 599	ebay.com
7.		Nikon D3200	5/5	+ +	..	73/100	4.5/5	4.5/5	Apr 2012	US$ 599	ebay.com
8.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	US$ 749	ebay.com
9.		Nikon D5100	5/5	+ +	..	76/100	4.5/5	4.5/5	Apr 2011	US$ 749	ebay.com
10.		Nikon D7000	4/5	..	..	80/100	4.5/5	4.5/5	Sep 2010	US$ 1 499	ebay.com
11.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	US$ 599	ebay.com
12.		Sony A6400	4/5	+	4/5	85/100	4.5/5	4/5	Jan 2019	US$ 899	amazon.com
13.		Sony NEX-5N	3/5	+ +	..	79/100	4.5/5	4.5/5	Aug 2011	US$ 699	ebay.com
14.		Sony NEX-6	5/5	+ +	..	78/100	4.5/5	4.5/5	Sep 2012	US$ 999	ebay.com
15.		Sony NEX-7	5/5	+ +	..	81/100	4.5/5	5/5	Aug 2011	US$ 1 349	ebay.com
16.		Sony NEX-C3	3/5	+ +	..	74/100	4.5/5	4/5	Jun 2011	US$ 599	ebay.com
17.		Sony RX1R	5/5	..	..	..	4/5	4.5/5	Jun 2013	US$ 2 799	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.

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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 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.

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