Nikon D3100 vs Pentax K-70

The Nikon D3100 and the Pentax K-70 are two digital cameras that were officially introduced, respectively, in August 2010 and June 2016. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Nikon has a resolution of 14.2 megapixels, whereas the Pentax 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		Pentax K-70
Digital single lens reflex		Digital single lens reflex
Nikon F mount lenses		Pentax K mount lenses
14.2 MP – APS-C sensor		24 MP – APS-C sensor
1080/24p Video		1080/60i Video
ISO 100-3,200 (100 - 12,800)		ISO 100-102,400
Optical viewfinder		Optical viewfinder
3.0" LCD – 230k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Swivel screen (not touch-sensitive)
3 shutter flaps per second		6 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
550 shots per battery charge		410 shots per battery charge
124 x 96 x 75 mm, 505 g		126 x 93 x 74 mm, 688 g

Check D3100 offers at
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Check K-70 offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D3100 and the Pentax K-70? 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 side-by-side display below illustrates the physical size and weight of the Nikon D3100 and the Pentax K-70. 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 K-70 is also available in two color-versions, but different ones (black, silver).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-70 is somewhat smaller (2 percent) than the Nikon D3100. However, the K-70 is substantially heavier (36 percent) than the D3100. It is noteworthy in this context that the K-70 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 K-70 can take 410 images on a single charge of its Pentax D-LI109 power pack.

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	Street Price
1.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	US$ 599	ebay.com
2.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	US$ 649	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 D3300	124 mm	98 mm	76 mm	430 g	700	n	Jan 2014	US$ 499	ebay.com
9.		Nikon D3400	124 mm	98 mm	76 mm	445 g	1200	n	Aug 2016	US$ 499	ebay.com
10.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	US$ 749	ebay.com
11.		Nikon D5100	128 mm	97 mm	79 mm	560 g	660	n	Apr 2011	US$ 749	ebay.com
12.		Nikon D5600	124 mm	97 mm	70 mm	465 g	970	n	Nov 2016	US$ 699	ebay.com
13.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	US$ 1 299	ebay.com
14.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	US$ 1 099	ebay.com
15.		Pentax K-50	130 mm	97 mm	71 mm	650 g	410	Y	Jun 2013	US$ 599	ebay.com
16.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	US$ 1 099	ebay.com
17.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	US$ 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

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 D3100 was somewhat cheaper (by 8 percent) than the K-70 at launch, but both cameras fall into the same price category. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 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. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to 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.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the K-70 is 3 percent bigger. 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 K-70 offers a higher resolution than the D3100 (14.2MP), but the K-70 has smaller individual pixels (pixel pitch of 3.91μm versus 5.01μm for the D3100). Yet, the K-70 is a much more recent model (by 5 years and 9 months) 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. Coming back to sensor resolution, it should be mentioned that the K-70 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax K-70 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-70 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 K-70 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

Unlike the D3100, the K-70 has the capacity to capture high quality composite images by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

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 Pentax K-70 are ISO 100 to ISO 102400 (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.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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"). The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.

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.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
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 D3300	APS-C	24.0	6000	4000	1080/60p	24.3	12.8	1385	82
9.		Nikon D3400	APS-C	24.0	6000	4000	1080/60p	24.8	13.9	1192	86
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 D5600	APS-C	24.0	6000	4000	1080/60p	24.1	14.0	1306	84
13.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
14.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
15.		Pentax K-50	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1120	79
16.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
17.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
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 also of capturing video footage. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the K-70 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 variety of features. The D3100 and the K-70 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 K-70 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 K-70 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 table below summarizes some of the other core capabilities of the Nikon D3100 and Pentax K-70 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.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
2.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
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 D3300	optical	n	3.0 / 921	fixed	n	1/4000s	5.0/s	Y	n
9.		Nikon D3400	optical	n	3.0 / 921	fixed	n	1/4000s	5.0/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 D5600	optical	n	3.2 / 1037	swivel	Y	1/4000s	5.0/s	Y	n
13.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
14.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
15.		Pentax K-50	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
16.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
17.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the K-70 and the D3100 is in-body image stabilization (IBIS). The K-70 reduces the risk of handshake-induced blur with all attached lenses, while the D3100 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The Pentax K-70 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 K-70 write their files to SDXC cards. The K-70 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 Nikon D3100 and Pentax K-70 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.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
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 D3300	Y	mono / mono	Y	-	mini	2.0	-	-	-
9.		Nikon D3400	Y	mono / mono	-	-	mini	2.0	-	-	Y
10.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-
11.		Nikon D5100	Y	mono / mono	Y	-	mini	2.0	-	-	-
12.		Nikon D5600	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
13.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
14.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax K-50	Y	mono / mono	-	-	micro	2.0	-	-	-
16.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
17.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-

It is notable that the K-70 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the D3100 does not provide wifi capability.

Both the D3100 and the K-70 have been discontinued, but can regularly be found used on ebay. The D3100 was replaced by the Nikon D3200, while the K-70 does not have a direct successor. Further information on the features and operation of the D3100 and K-70 can be found, respectively, in the Nikon D3100 Manual (free pdf) or the online Pentax K-70 Manual.

Review summary

So how do things add up? Is the Nikon D3100 better than the Pentax K-70 or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Nikon D3100:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Less heavy: Is lighter (by 183g or 27 percent) and hence easier to carry around.
• Longer lasting: Can take more shots (550 versus 410) on a single battery charge.
• More heavily discounted: Has been available for much longer (launched in August 2010).

Reasons to prefer the Pentax K-70:

• 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.
• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Better video: Provides higher movie framerates (1080/60i versus 1080/24p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• 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).
• More detailed LCD: Has a higher resolution rear screen (921k vs 230k dots).
• 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.
• Faster shutter: Has higher mechanical shutter speed (1/6000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (6 vs 3 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Reflects 5 years and 9 months of technical progress since the D3100 launch.

If the count of relative strengths (bullet points above) is taken as a measure, the K-70 is the clear winner of the contest (19 : 4 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 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 Pentax K-70 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 partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the D3100 or the K-70. 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 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	Street Price
1.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	US$ 599	ebay.com
2.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	US$ 649	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 D3300	3/5	+	..	77/100	4.5/5	4.5/5	Jan 2014	US$ 499	ebay.com
9.		Nikon D3400	4/5	+	4/5	76/100	4/5	4.5/5	Aug 2016	US$ 499	ebay.com
10.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	US$ 749	ebay.com
11.		Nikon D5100	5/5	+ +	..	76/100	4.5/5	4.5/5	Apr 2011	US$ 749	ebay.com
12.		Nikon D5600	4/5	..	4/5	79/100	4.5/5	4/5	Nov 2016	US$ 699	ebay.com
13.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	US$ 1 299	ebay.com
14.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	US$ 1 099	ebay.com
15.		Pentax K-50	5/5	..	..	..	5/5	4.5/5	Jun 2013	US$ 599	ebay.com
16.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	US$ 1 099	ebay.com
17.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	US$ 749	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. 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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