Sony A7 vs Nikon D5100

The Sony Alpha A7 and the Nikon D5100 are two digital cameras that were revealed to the public, respectively, in October 2013 and April 2011. The A7 is a mirrorless interchangeable lens camera, while the D5100 is a DSLR. The cameras are based on a full frame (A7) and an APS-C (D5100) sensor. The Sony has a resolution of 24 megapixels, whereas the Nikon provides 16.1 MP.

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

Headline Specifications

Sony A7		Nikon D5100
Mirrorless system camera		Digital single lens reflex
Sony E mount lenses		Nikon F mount lenses
24 MP – Full Frame sensor		16.1 MP – APS-C sensor
1080/60p Video		1080/30p Video
ISO 100-25,600 (50 - 51,200)		ISO 100-6,400 (100 - 25,600)
Electronic viewfinder (2400k dots)		Optical viewfinder
3.0" LCD – 1230k dots		3.0" LCD – 921k dots
Tilting screen (no touchscreen)		Swivel screen (not touch-sensitive)
5 shutter flaps per second		4 shutter flaps per second
Weathersealed body		not weather sealed
340 shots per battery charge		660 shots per battery charge
127 x 94 x 48 mm, 474 g		128 x 97 x 79 mm, 560 g

Check A7 offers at
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Check D5100 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 Nikon D5100? 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 Nikon D5100 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.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Nikon D5100 is somewhat larger (4 percent) than the Sony A7. Moreover, the D5100 is markedly heavier (18 percent) than the A7. It is worth mentioning in this context that the A7 is splash and dust resistant, while the D5100 does not feature any corresponding weather-sealing.

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 Nikon Lens Catalog (D5100). Mirrorless cameras, such as the Sony A7, 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 A7 gets 340 shots out of its Sony NP-FW50 battery, while the D5100 can take 660 images on a single charge of its Nikon EN-EL14 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 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.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	1,699	ebay.com
2.		Nikon D5100	128 mm	97 mm	79 mm	560 g	660	n	Apr 2011	749	ebay.com
3.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
4.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	599	ebay.com
5.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	749	ebay.com
6.		Nikon D5200	129 mm	98 mm	78 mm	555 g	500	n	Nov 2012	749	ebay.com
7.		Nikon D5300	125 mm	98 mm	76 mm	480 g	600	n	Oct 2013	799	ebay.com
8.		Nikon D5500	124 mm	97 mm	70 mm	470 g	820	n	Jan 2015	899	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.
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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 D5100 was launched at a markedly lower price (by 56 percent) than the A7, 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.

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 Nikon D5100 an APS-C sensor. The sensor area in the D5100 is 57 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 24MP, the A7 offers a higher resolution than the D5100 (16.1MP), but the A7 nevertheless has larger individual pixels (pixel pitch of 5.97μm versus 4.80μm for the D5100) due to its larger sensor. Moreover, the A7 is a much more recent model (by 2 years and 6 months) than the D5100, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels.

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 Nikon D5100 are 24.6 x 16.3 inches or 62.6 x 41.5 cm for good quality, 19.7 x 13.1 inches or 50.1 x 33.2 cm for very good quality, and 16.4 x 10.9 inches or 41.7 x 27.6 cm for excellent quality prints.

The A7 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

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 Nikon D5100 are ISO 100 to ISO 6400, 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 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 has a notably higher overall DXO score than the D5100 (overall score 10 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 1.3 bits higher color depth, 0.6 EV in additional dynamic range, and 0.9 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.		Nikon D5100	APS-C	16.1	4928	3264	1080/30p	23.5	13.6	1183	80
3.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
4.		Nikon D3100	APS-C	14.2	4608	3072	1080/24p	22.5	11.3	919	67
5.		Nikon D5000	APS-C	12.2	4288	2848	720/24p	22.7	12.5	868	72
6.		Nikon D5200	APS-C	24.0	6000	4000	1080/60i	24.2	13.9	1284	84
7.		Nikon D5300	APS-C	24.0	6000	4000	1080/60p	24.0	13.9	1338	83
8.		Nikon D5500	APS-C	24.0	6000	4000	1080/60p	24.1	14.0	1438	84
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 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 A7 provides a higher frame rate than the D5100. It can shoot video footage at 1080/60p, while the Nikon is limited to 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A7 has an electronic viewfinder (2400k dots), while the D5100 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 A7 offers a wider field of view (100%) than the one in the D5100 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A7 has a higher magnification (0.71x vs 0.51x), 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 Sony A7, the Nikon D5100, 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.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
2.		Nikon D5100	optical	n	3.0 / 921	swivel	n	1/4000s	4.0/s	Y	n
3.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
4.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
5.		Nikon D5000	optical	n	2.7 / 230	full-flex	n	1/4000s	4.0/s	Y	n
6.		Nikon D5200	optical	n	3.0 / 921	swivel	n	1/4000s	5.0/s	Y	n
7.		Nikon D5300	optical	n	3.2 / 1037	swivel	n	1/4000s	5.0/s	Y	n
8.		Nikon D5500	optical	n	3.2 / 1037	swivel	Y	1/4000s	5.0/s	Y	n
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 difference between the cameras concerns the presence of an on-board flash. The D5100 has one, while the A7 does not. While the built-in flash of the D5100 is not very powerful, it can at times be useful as a fill-in light.

The Nikon D5100 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 D5100 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 Nikon D5100 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.		Nikon D5100	Y	mono / mono	Y	-	mini	2.0	-	-	-
3.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
4.		Nikon D3100	Y	mono / mono	-	-	mini	2.0	-	-	-
5.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-
6.		Nikon D5200	Y	stereo / mono	Y	-	mini	2.0	-	-	-
7.		Nikon D5300	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
8.		Nikon D5500	Y	stereo / mono	Y	-	mini	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 D5100 This port makes it possible to attach external headphones and monitor the quality of sound during the recording process.

Both the A7 and the D5100 have been discontinued, but can regularly be found used on ebay. The D5100 was replaced by the Nikon D5200, while the A7 was followed by the Sony A7 II. Further information on the features and operation of the A7 and D5100 can be found, respectively, in the Sony A7 Manual (free pdf) or the online Nikon D5100 Manual.

Review summary

So what is the bottom line? Is the Sony A7 better than the Nikon D5100 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Sony Alpha A7:

• More detail: Offers more megapixels (24 vs 16.1MP) with a 22% higher linear resolution.
• Better image quality: Scores markedly higher (10 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 (0.6 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (0.9 stops ISO advantage).
• Better video: Provides higher movie framerates (1080/60p versus 1080/30p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• 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 (0.71x vs 0.51x).
• More detailed LCD: Has a higher resolution rear screen (1230k vs 921k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (5 vs 4 flaps/sec) to capture the decisive moment.
• Less heavy: Is lighter (by 86g or 15 percent) and hence easier to carry around.
• Easier travel charging: Can be conveniently charged via its USB port.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• 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.
• More modern: Reflects 2 years and 6 months of technical progress since the D5100 launch.

Arguments in favor of the Nikon D5100:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Gets more shots (660 versus 340) out of a single battery charge.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• More affordable: Was introduced into a lower priced category (56 percent cheaper at launch).
• More heavily discounted: Has been around for much longer (launched in April 2011).

If the number of relative strengths (bullet points above) is taken as a guide, the A7 is the clear winner of the match-up (21 : 8 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 Sony A7 and the Nikon D5100 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 technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the A7 or the D5100. 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 expert reviews 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 A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	1,699	ebay.com
2.		Nikon D5100	5/5	+ +	..	76/100	4.5/5	4.5/5	Apr 2011	749	ebay.com
3.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
4.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	599	ebay.com
5.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	749	ebay.com
6.		Nikon D5200	4/5	+ +	..	79/100	4.5/5	4.5/5	Nov 2012	749	ebay.com
7.		Nikon D5300	4/5	+ +	..	79/100	4.5/5	4.5/5	Oct 2013	799	ebay.com
8.		Nikon D5500	5/5	+	..	79/100	4.5/5	4.5/5	Jan 2015	899	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.

The review scores listed above should be treated with care, 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 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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