Nikon D3100 vs Sigma fp

The Nikon D3100 and the Sigma fp are two digital cameras that were announced, respectively, in August 2010 and July 2019. The D3100 is a DSLR, while the fp is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (D3100) and a full frame (fp) sensor. The Nikon has a resolution of 14.2 megapixels, whereas the Sigma provides 24 MP.

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

Headline Specifications

Nikon D3100		Sigma fp
Digital single lens reflex		Mirrorless system camera
Nikon F mount lenses		Leica L mount lenses
14.2 MP – APS-C sensor		24 MP – Full Frame sensor
1080/24p Video		4K/30p Video
ISO 100-3,200 (100 - 12,800)		ISO 100-25,600 (6 - 102,400)
Optical viewfinder		Viewfinder optional
3.0" LCD – 230k dots		3.2" LCD – 2100k dots
Fixed screen (not touch-sensitive)		Fixed touchscreen
3 shutter flaps per second		12 shutter flaps per second
not weather sealed		Weathersealed body
550 shots per battery charge		280 shots per battery charge
124 x 96 x 75 mm, 505 g		113 x 70 x 45 mm, 422 g

Check D3100 offers at
ebay.com
Check fp price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D3100 and the Sigma fp? 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 Nikon D3100 and the Sigma fp 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 D3100 can be obtained in two different colors (black, red), while the fp 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 Sigma fp is considerably smaller (34 percent) than the Nikon D3100. Moreover, the fp is markedly lighter (16 percent) than the D3100. It is noteworthy in this context that the fp is splash and dust-proof, 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. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

Concerning battery life, the D3100 gets 550 shots out of its Nikon EN-EL14 battery, while the fp can take 280 images on a single charge of its Sigma BP-51 power pack. The power pack in the fp can be charged via the USB port, which can be very convenient when travelling.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons 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.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	599	ebay.com
2.		Sigma fp	113 mm	70 mm	45 mm	422 g	280	Y	Jul 2019	1,899	amazon.com
3.		Fujifilm X-Pro3	141 mm	83 mm	46 mm	497 g	440	Y	Oct 2019	1,799	amazon.com
4.		Nikon D40	124 mm	94 mm	64 mm	522 g	470	n	Nov 2006	499	ebay.com
5.		Nikon D40X	124 mm	94 mm	64 mm	522 g	520	n	Mar 2007	729	ebay.com
6.		Nikon D60	126 mm	94 mm	64 mm	522 g	500	n	Jan 2008	629	ebay.com
7.		Nikon D780	144 mm	116 mm	76 mm	840 g	2260	Y	Jan 2020	2,299	amazon.com
8.		Nikon D3000	126 mm	97 mm	64 mm	536 g	500	n	Jul 2009	599	ebay.com
9.		Nikon D3200	125 mm	96 mm	77 mm	505 g	540	n	Apr 2012	599	ebay.com
10.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	749	ebay.com
11.		Nikon D5100	128 mm	97 mm	79 mm	560 g	660	n	Apr 2011	749	ebay.com
12.		Nikon D7000	132 mm	105 mm	77 mm	780 g	1050	Y	Sep 2010	1,499	ebay.com
13.		Panasonic S1	149 mm	110 mm	97 mm	1017 g	400	Y	Feb 2019	2,499	amazon.com
14.		Panasonic S1H	151 mm	114 mm	110 mm	1052 g	400	Y	May 2019	3,999	amazon.com
15.		Panasonic S5	133 mm	98 mm	82 mm	714 g	440	Y	Sep 2020	1,999	amazon.com
16.		Sony NEX-5N	111 mm	59 mm	38 mm	269 g	460	n	Aug 2011	699	ebay.com
17.		Sony NEX-C3	110 mm	60 mm	33 mm	225 g	400	n	Jun 2011	599	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 naturally be influenced heavily by the price. 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 68 percent) than the fp, 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 imaging sensor is a crucial determinant of image quality. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and 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.

Of the two cameras under consideration, the Nikon D3100 features an APS-C sensor and the Sigma fp a full frame sensor. The sensor area in the fp is 141 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 24MP, the fp offers a higher resolution than the D3100 (14.2MP), but the fp nevertheless has larger individual pixels (pixel pitch of 5.98μm versus 5.01μm for the D3100) due to its larger sensor. Moreover, the fp is a much more recent model (by 8 years and 10 months) than the D3100, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the fp has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Sigma fp implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the fp 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 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 Sigma fp are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 6-102400.

In terms of underlying technology, the D3100 is build around a CMOS sensor, while the fp uses a BSI-CMOS imager. 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"). 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.		Sigma fp	Full Frame	24.0	6000	4000	4K/30p	25.2	14.2	2829	94
3.		Fujifilm X-Pro3	APS-C	26.0	6240	4160	4K/30p	24.1	13.6	1968	84
4.		Nikon D40	APS-C	6.0	3008	2000	none	21.0	11.0	561	56
5.		Nikon D40X	APS-C	10.0	3872	2592	none	22.4	11.4	516	63
6.		Nikon D60	APS-C	10.0	3872	2592	none	22.5	11.4	562	65
7.		Nikon D780	Full Frame	24.3	6048	4024	4K/30p	25.3	14.3	2877	95
8.		Nikon D3000	APS-C	10.0	3872	2592	none	22.3	11.1	563	62
9.		Nikon D3200	APS-C	24.1	6016	4000	1080/30p	24.1	13.2	1131	81
10.		Nikon D5000	APS-C	12.2	4288	2848	720/24p	22.7	12.5	868	72
11.		Nikon D5100	APS-C	16.1	4928	3264	1080/30p	23.5	13.6	1183	80
12.		Nikon D7000	APS-C	16.1	4928	3264	1080/24p	23.5	13.9	1167	80
13.		Panasonic S1	Full Frame	24.0	6000	4000	4K/60p	25.2	14.5	3333	95
14.		Panasonic S1H	Full Frame	24.0	6000	4000	6K/30p	25.2	14.2	2805	94
15.		Panasonic S5	Full Frame	24.0	6000	4000	4K/60p	25.1	14.5	2697	94
16.		Sony NEX-5N	APS-C	16.0	4912	3264	1080/60i	23.6	12.7	1079	77
17.		Sony NEX-C3	APS-C	16.0	4912	3264	720/30p	22.7	12.2	1083	73
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 fp 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 variety of features. For example, the D3100 has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the fp relies on live view and the rear LCD for framing. That said, the fp can be equipped with an optional viewfinder – the EVF-11. The following table reports on some other key feature differences and similarities of the Nikon D3100, the Sigma fp, 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.		Sigma fp	optional	n	3.2 / 2100	fixed	Y	1/8000s	12.0/s	n	n
3.		Fujifilm X-Pro3	3690	n	3.0 / 1620	tilting	Y	1/8000s	8.0/s	n	n
4.		Nikon D40	optical	n	2.5 / 230	fixed	n	1/4000s	2.5/s	Y	n
5.		Nikon D40X	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
6.		Nikon D60	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
7.		Nikon D780	optical	Y	3.2 / 2359	tilting	Y	1/8000s	12.0/s	n	n
8.		Nikon D3000	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
9.		Nikon D3200	optical	n	3.0 / 921	fixed	n	1/4000s	4.0/s	Y	n
10.		Nikon D5000	optical	n	2.7 / 230	full-flex	n	1/4000s	4.0/s	Y	n
11.		Nikon D5100	optical	n	3.0 / 921	swivel	n	1/4000s	4.0/s	Y	n
12.		Nikon D7000	optical	Y	3.0 / 921	fixed	n	1/8000s	6.0/s	Y	n
13.		Panasonic S1	5760	Y	3.2 / 2100	full-flex	Y	1/8000s	9.0/s	n	Y
14.		Panasonic S1H	5760	Y	3.2 / 2330	swivel	Y	1/8000s	9.0/s	n	Y
15.		Panasonic S5	2360	n	3.0 / 1840	swivel	Y	1/8000s	7.0/s	n	Y
16.		Sony NEX-5N	optional	n	3.0 / 920	tilting	Y	1/4000s	10.0/s	n	n
17.		Sony NEX-C3	optional	n	3.0 / 920	tilting	n	1/4000s	5.5/s	n	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 D3100 has one, while the fp does not. While the built-in flash of the D3100 is not very powerful, it can at times be useful as a fill-in light.

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 fp 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 Sigma fp 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 fp write their files to SDXC cards. The fp 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 Sigma fp 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.		Sigma fp	Y	stereo / mono	Y	-	micro	3.1	-	-	-
3.		Fujifilm X-Pro3	Y	stereo / mono	Y	-	-	3.1	Y	-	Y
4.		Nikon D40	Y	- / -	-	-	-	2.0	-	-	-
5.		Nikon D40X	Y	- / -	-	-	-	2.0	-	-	-
6.		Nikon D60	Y	- / -	-	-	-	2.0	-	-	-
7.		Nikon D780	Y	stereo / mono	Y	Y	mini	3.1	Y	-	Y
8.		Nikon D3000	Y	- / -	-	-	-	2.0	-	-	-
9.		Nikon D3200	Y	mono / mono	Y	-	mini	2.0	-	-	-
10.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-
11.		Nikon D5100	Y	mono / mono	Y	-	mini	2.0	-	-	-
12.		Nikon D7000	Y	mono / mono	Y	-	mini	2.0	-	-	-
13.		Panasonic S1	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
14.		Panasonic S1H	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
15.		Panasonic S5	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
16.		Sony NEX-5N	Y	stereo / mono	-	-	mini	2.0	-	-	-
17.		Sony NEX-C3	Y	stereo / mono	-	-	mini	2.0	-	-	-

It is notable that the fp has a microphone port, which can help to improve the quality of audio recordings by attaching an external microphone. The D3100 does not feature such a mic input.

The fp is a recent model that features in the current product line-up of Sigma. In contrast, the D3100 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the D3100 was succeeded by the Nikon D3200. Further information on the features and operation of the D3100 and fp can be found, respectively, in the Nikon D3100 Manual (free pdf) or the online Sigma fp Manual.

Review summary

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

Reasons to prefer the Nikon D3100:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Longer lasting: Can take more shots (550 versus 280) on a single battery charge.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (68 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2010).

Arguments in favor of the Sigma fp:

• More detail: Has more megapixels (24 vs 14.2MP), which boosts linear resolution by 30%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Is equipped with a larger and more technologically advanced sensor.
• Richer colors: The sensor size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger sensor captures a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger sensor produces good images even in poorly lit environments.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/24p).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (2100k vs 230k dots).
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (12 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 (113x70mm vs 124x96mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 83g or 16 percent) and is thus easier to take along.
• Easier travel charging: Can be conveniently charged via its USB port.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
• Faster buffer clearing: Has an SD card interface that supports the UHS-II standard.
• More modern: Reflects 8 years and 10 months of technical progress since the D3100 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the fp is the clear winner of the contest (23 : 6 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 Nikon D3100 and the Sigma fp 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 fp. 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 (USD)	Street Price
1.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	599	ebay.com
2.		Sigma fp	4/5	..	4/5	..	4/5	4.5/5	Jul 2019	1,899	amazon.com
3.		Fujifilm X-Pro3	4/5	+	4/5	85/100	4/5	..	Oct 2019	1,799	amazon.com
4.		Nikon D40	..	81/100	..	+ +	o	4.5/5	Nov 2006	499	ebay.com
5.		Nikon D40X	..	79/100	..	+ +	4/5	4/5	Mar 2007	729	ebay.com
6.		Nikon D60	..	80/100	..	+ +	4/5	4.5/5	Jan 2008	629	ebay.com
7.		Nikon D780	5/5	..	5/5	87/100	4.5/5	4.5/5	Jan 2020	2,299	amazon.com
8.		Nikon D3000	..	+	..	72/100	4/5	4.5/5	Jul 2009	599	ebay.com
9.		Nikon D3200	5/5	+ +	..	73/100	4.5/5	4.5/5	Apr 2012	599	ebay.com
10.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	749	ebay.com
11.		Nikon D5100	5/5	+ +	..	76/100	4.5/5	4.5/5	Apr 2011	749	ebay.com
12.		Nikon D7000	4/5	..	..	80/100	4.5/5	4.5/5	Sep 2010	1,499	ebay.com
13.		Panasonic S1	4.5/5	+ +	4.5/5	88/100	4.5/5	4/5	Feb 2019	2,499	amazon.com
14.		Panasonic S1H	..	..	4/5	90/100	..	..	May 2019	3,999	amazon.com
15.		Panasonic S5	4.5/5	+ +	4.5/5	88/100	4.5/5	4.5/5	Sep 2020	1,999	amazon.com
16.		Sony NEX-5N	3/5	+ +	..	79/100	4.5/5	4.5/5	Aug 2011	699	ebay.com
17.		Sony NEX-C3	3/5	+ +	..	74/100	4.5/5	4/5	Jun 2011	599	ebay.com
Note: (+ +) 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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. 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

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