Canon 7D vs Nikon D3100

The Canon EOS 7D and the Nikon D3100 are two digital cameras that were revealed to the public, respectively, in September 2009 and August 2010. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Canon has a resolution of 17.9 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

Canon 7D		Nikon D3100
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Nikon F mount lenses
17.9 MP – APS-C sensor		14.2 MP – APS-C sensor
1080/30p Video		1080/24p Video
ISO 100-6,400 (100 - 12,800)		ISO 100-3,200 (100 - 12,800)
Optical viewfinder		Optical viewfinder
3.0" LCD – 920k dots		3.0" LCD – 230k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
8 shutter flaps per second		3 shutter flaps per second
Weathersealed body		not weather sealed
800 shots per battery charge		550 shots per battery charge
148 x 111 x 74 mm, 860 g		124 x 96 x 75 mm, 505 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS 7D 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 Canon 7D 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 dimensions are rounded to the nearest millimeter.

The D3100 can be obtained in two different colors (black, red), while the 7D 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 Nikon D3100 is notably smaller (28 percent) than the Canon 7D. Moreover, the D3100 is substantially lighter (41 percent) than the 7D. It is worth mentioning in this context that the 7D is splash and dust resistant, while the D3100 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. Yet, since both cameras are based around an APS-C sensor, their respective lenses will tend to have similar dimensions and heft. You can compare the optics available for the two cameras in the Canon EF Lens Catalog (7D) and the Nikon Lens Catalog (D3100).

Concerning battery life, the 7D gets 800 shots out of its LP-E6 battery, while the D3100 can take 550 images on a single charge of its EN-EL14 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.		Canon 7D	148 mm	111 mm	74 mm	860 g	800	Y	Sep 2009	1,699	ebay.com
2.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	599	ebay.com
3.		Canon 7D II	149 mm	112 mm	78 mm	910 g	670	Y	Sep 2014	1,799	ebay.com
4.		Canon 70D	139 mm	104 mm	79 mm	755 g	920	Y	Jul 2013	1,199	ebay.com
5.		Canon 60D	145 mm	106 mm	79 mm	755 g	1100	Y	Aug 2010	1,399	ebay.com
6.		Canon T2i	129 mm	98 mm	62 mm	530 g	440	n	Feb 2010	699	ebay.com
7.		Canon T1i	129 mm	98 mm	62 mm	520 g	400	n	Mar 2009	799	ebay.com
8.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
9.		Canon 50D	146 mm	108 mm	74 mm	822 g	800	Y	Aug 2008	1,299	ebay.com
10.		Canon 30D	144 mm	106 mm	74 mm	785 g	750	n	Feb 2006	1,399	ebay.com
11.		Canon 20D	144 mm	106 mm	72 mm	770 g	700	n	Aug 2004	1,499	ebay.com
12.		Nikon D3200	125 mm	96 mm	77 mm	505 g	540	n	Apr 2012	599	ebay.com
13.		Nikon D5100	128 mm	97 mm	79 mm	560 g	660	n	Apr 2011	749	ebay.com
14.		Nikon D7000	132 mm	105 mm	77 mm	780 g	1050	Y	Sep 2010	1,499	ebay.com
15.		Nikon D3000	126 mm	97 mm	64 mm	536 g	500	n	Jul 2009	599	ebay.com
16.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	749	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 manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The D3100 was launched at a markedly lower price (by 65 percent) than the 7D, 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 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. 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 7 percent bigger. As a result of these sensor size differences, the cameras have format factors, respectively, of 1.6 (7D) and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Despite having a smaller sensor, the Canon 7D offers a higher resolution of 17.9 megapixels, compared with 14.2 MP of the Nikon 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 4.31μm versus 5.01μm for the D3100). Moreover, it should be noted that the D3100 is a somewhat more recent model (by 11 months) than the 7D, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units.

The resolution advantage of the Canon 7D implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 7D for good quality output (200 dots per inch) amounts to 25.9 x 17.3 inches or 65.8 x 43.9 cm, for very good quality (250 dpi) 20.7 x 13.8 inches or 52.7 x 35.1 cm, and for excellent quality (300 dpi) 17.3 x 11.5 inches or 43.9 x 29.3 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 Canon EOS 7D has a native sensitivity range from ISO 100 to ISO 6400, which can be extended to ISO 100-12800. 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.

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 Overall DXO ratings for the two cameras under consideration are close, suggesting that they provide similar imaging performance. 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.		Canon 7D	APS-C	17.9	5184	3456	1080/30p	22.0	11.7	854	66
2.		Nikon D3100	APS-C	14.2	4608	3072	1080/24p	22.5	11.3	919	67
3.		Canon 7D II	APS-C	20.0	5472	3648	1080/60p	22.4	11.8	1082	70
4.		Canon 70D	APS-C	20.0	5472	3648	1080/30p	22.5	11.6	926	68
5.		Canon 60D	APS-C	17.9	5184	3456	1080/30p	22.2	11.5	813	66
6.		Canon T2i	APS-C	17.9	5184	3456	1080/30p	22.1	11.5	784	66
7.		Canon T1i	APS-C	15.1	4752	3168	1080/20p	21.7	11.5	663	63
8.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
9.		Canon 50D	APS-C	15.1	4752	3168	none	21.8	11.4	696	63
10.		Canon 30D	APS-C	8.2	3504	2336	none	21.5	10.8	736	59
11.		Canon 20D	APS-C	8.2	3504	2336	none	21.9	11.0	721	62
12.		Nikon D3200	APS-C	24.1	6016	4000	1080/30p	24.1	13.2	1131	81
13.		Nikon D5100	APS-C	16.1	4928	3264	1080/30p	23.5	13.6	1183	80
14.		Nikon D7000	APS-C	16.1	4928	3264	1080/24p	23.5	13.9	1167	80
15.		Nikon D3000	APS-C	10.0	3872	2592	none	22.3	11.1	563	62
16.		Nikon D5000	APS-C	12.2	4288	2848	720/24p	22.7	12.5	868	72

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 7D provides a higher frame rate than the D3100. It can shoot video footage at 1080/30p, while the Nikon is limited to 1080/24p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The 7D and the D3100 are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The viewfinder in the 7D 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 7D has a higher magnification (0.63x vs 0.53x), 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 Canon 7D and Nikon D3100 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.		Canon 7D	optical	Y	3.0 / 920	fixed	n	1/8000s	8.0/s	Y	n
2.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
3.		Canon 7D II	optical	Y	3.0 / 1040	fixed	n	1/8000s	10.0/s	Y	n
4.		Canon 70D	optical	Y	3.0 / 1040	swivel	Y	1/8000s	7.0/s	Y	n
5.		Canon 60D	optical	Y	3.0 / 1040	swivel	n	1/8000s	5.3/s	Y	n
6.		Canon T2i	optical	n	3.0 / 1040	fixed	n	1/4000s	3.7/s	Y	n
7.		Canon T1i	optical	n	3.0 / 920	fixed	n	1/4000s	3.4/s	Y	n
8.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
9.		Canon 50D	optical	Y	3.0 / 920	fixed	n	1/8000s	6.3/s	Y	n
10.		Canon 30D	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
11.		Canon 20D	optical	Y	1.8 / 118	fixed	n	1/8000s	5.0/s	Y	n
12.		Nikon D3200	optical	n	3.0 / 921	fixed	n	1/4000s	4.0/s	Y	n
13.		Nikon D5100	optical	n	3.0 / 921	swivel	n	1/4000s	4.0/s	Y	n
14.		Nikon D7000	optical	Y	3.0 / 921	fixed	n	1/8000s	6.0/s	Y	n
15.		Nikon D3000	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
16.		Nikon D5000	optical	n	2.7 / 230	full-flex	n	1/4000s	4.0/s	Y	n
Notes: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the 7D, but is missing on the D3100 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The 7D writes its imaging data to Compact Flash cards, while the D3100 uses SDXC 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 Canon EOS 7D 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.		Canon 7D	Y	mono / -	Y	-	mini	2.0	-	-	-
2.		Nikon D3100	Y	mono / mono	-	-	mini	2.0	-	-	-
3.		Canon 7D II	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
4.		Canon 70D	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
5.		Canon 60D	Y	mono / mono	Y	-	mini	2.0	-	-	-
6.		Canon T2i	Y	stereo / -	Y	-	mini	2.0	-	-	-
7.		Canon T1i	Y	mono / mono	-	-	mini	2.0	-	-	-
8.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
9.		Canon 50D	Y	- / -	-	-	mini	2.0	-	-	-
10.		Canon 30D	Y	- / -	-	-	-	2.0	-	-	-
11.		Canon 20D	Y	- / -	-	-	-	1.1	-	-	-
12.		Nikon D3200	Y	mono / mono	Y	-	mini	2.0	-	-	-
13.		Nikon D5100	Y	mono / mono	Y	-	mini	2.0	-	-	-
14.		Nikon D7000	Y	mono / mono	Y	-	mini	2.0	-	-	-
15.		Nikon D3000	Y	- / -	-	-	-	2.0	-	-	-
16.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-

It is notable that the 7D has a microphone port, which is missing on the D3100. Such an external microphone input can help to substantially improve the quality of audio recordings when a good external microphone is used.

Studio photographers will appreciate that the Canon 7D (unlike the D3100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 7D and the D3100 have been discontinued, but can regularly be found used on ebay. The 7D was replaced by the Canon 7D Mark II, while the D3100 was followed by the Nikon D3200. Further information on the features and operation of the 7D and D3100 can be found, respectively, in the Canon 7D Manual (free pdf) or the online Nikon D3100 Manual.

Review summary

So what conclusions can be drawn? Is the Canon 7D better than the Nikon D3100 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Canon EOS 7D:

• More detail: Offers more megapixels (17.9 vs 14.2MP) with a 12% higher linear resolution.
• Better video: Provides higher movie framerates (1080/30p versus 1080/24p).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• 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 (0.63x vs 0.53x).
• Easier setting verification: Features an LCD display on top to control shooting parameters.
• More detailed LCD: Has a higher resolution rear screen (920k vs 230k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (8 vs 3 flaps/sec) to capture the decisive moment.
• Longer lasting: Can take more shots (800 versus 550) on a single battery charge.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More heavily discounted: Has been on the market for longer (launched in September 2009).

Arguments in favor of the Nikon D3100:

• More compact: Is smaller (124x96mm vs 148x111mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 355g or 41 percent) and is thus easier to take along.
• More affordable: Was introduced into a lower priced category (65 percent cheaper at launch).
• More modern: Was introduced somewhat (11 months) more recently.

If the count of relative strengths (bullet points above) is taken as a measure, the 7D is the clear winner of the match-up (13 : 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 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 Canon 7D and the Nikon D3100 place the cameras among the top in their class? Find out in the latest Best DSLR 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 7D or the D3100 perform in practice. 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 expert reviews 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.		Canon 7D	5/5	+ +	..	84/100	4.5/5	4.5/5	Sep 2009	1,699	ebay.com
2.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	599	ebay.com
3.		Canon 7D II	4.5/5	+	3.5/5	84/100	4/5	4.5/5	Sep 2014	1,799	ebay.com
4.		Canon 70D	5/5	+ +	..	83/100	4.5/5	5/5	Jul 2013	1,199	ebay.com
5.		Canon 60D	5/5	+	..	79/100	4/5	4.5/5	Aug 2010	1,399	ebay.com
6.		Canon T2i	..	+ +	..	77/100	4/5	4.5/5	Feb 2010	699	ebay.com
7.		Canon T1i	..	+ +	..	74/100	4.5/5	4.5/5	Mar 2009	799	ebay.com
8.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
9.		Canon 50D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2008	1,299	ebay.com
10.		Canon 30D	..	+ +	..	+ +	o	..	Feb 2006	1,399	ebay.com
11.		Canon 20D	..	..	..	+ +	..	..	Aug 2004	1,499	ebay.com
12.		Nikon D3200	5/5	+ +	..	73/100	4.5/5	4.5/5	Apr 2012	599	ebay.com
13.		Nikon D5100	5/5	+ +	..	76/100	4.5/5	4.5/5	Apr 2011	749	ebay.com
14.		Nikon D7000	4/5	..	..	80/100	4.5/5	4.5/5	Sep 2010	1,499	ebay.com
15.		Nikon D3000	..	+	..	72/100	4/5	4.5/5	Jul 2009	599	ebay.com
16.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	749	ebay.com
Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, 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 comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. 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

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