Nikon D7100 vs Pentax K-3 III

The Nikon D7100 and the Pentax K-3 III are two enthusiast cameras that were announced, respectively, in February 2013 and March 2021. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Nikon has a resolution of 24 megapixels, whereas the Pentax provides 25.6 MP.

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

Headline Specifications

Nikon D7100		Pentax K-3 III
Digital single lens reflex		Digital single lens reflex
Nikon F mount lenses		Pentax K mount lenses
24 MP – APS-C sensor		25.6 MP – APS-C sensor
1080/60p Video		4K/30p Video
ISO 100-6,400 (50 - 25,600)		ISO 100-160,000
Optical viewfinder		Optical viewfinder
3.2" LCD – 1229k dots		3.2" LCD – 1620k dots
Fixed screen (not touch-sensitive)		Fixed touchscreen
6 shutter flaps per second		12 shutter flaps per second
Lens stabilization only		In-body stabilization
Weathersealed body		Weathersealed body
950 shots per battery charge		800 shots per battery charge
136 x 107 x 76 mm, 765 g		135 x 104 x 74 mm, 820 g

Check D7100 offers at
ebay.com
Check K-3 III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D7100 and the Pentax K-3 III? 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 D7100 and the Pentax K-3 III. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All size dimensions are rounded to the nearest millimeter.

The K-3 III can be obtained in two different colors (black, silver), while the D7100 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 Pentax K-3 III is somewhat smaller (4 percent) than the Nikon D7100. However, the K-3 III is markedly heavier (7 percent) than the D7100. In this context, it is worth noting that both cameras are splash and dust-proof and can, hence, be used in inclement weather conditions or harsh environments.

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 D7100 gets 950 shots out of its Nikon EN-EL15 battery, while the K-3 III can take 800 images on a single charge of its Pentax D-LI90 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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 D7100	136 mm	107 mm	76 mm	765 g	950	Y	Feb 2013	1,199	ebay.com
2.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
3.		Canon 70D	139 mm	104 mm	79 mm	755 g	920	Y	Jul 2013	1,199	ebay.com
4.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	1,899	ebay.com
5.		Nikon D7500	136 mm	104 mm	73 mm	720 g	950	Y	Apr 2017	1,299	amazon.com
6.		Nikon D500	147 mm	115 mm	81 mm	860 g	1240	Y	Jan 2016	1,999	ebay.com
7.		Nikon D7200	136 mm	107 mm	76 mm	765 g	1110	Y	Mar 2015	1,199	ebay.com
8.		Nikon D750	141 mm	113 mm	78 mm	750 g	1230	Y	Sep 2014	2,299	ebay.com
9.		Nikon D3300	124 mm	98 mm	76 mm	430 g	700	n	Jan 2014	499	ebay.com
10.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
11.		Nikon D600	141 mm	113 mm	82 mm	850 g	900	Y	Sep 2012	2,099	ebay.com
12.		Nikon D7000	132 mm	105 mm	77 mm	780 g	1050	Y	Sep 2010	1,499	ebay.com
13.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
14.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
15.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
16.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
17.		Sony RX10	129 mm	88 mm	102 mm	813 g	420	Y	Oct 2013	1,299	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 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 D7100 was launched at a markedly lower price (by 40 percent) than the K-3 III, 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. 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. 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 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-3 III is 2 percent smaller. 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.

Despite having a slightly smaller sensor, the K-3 III offers a slightly higher resolution of 25.6 megapixels, compared with 24 MP of the D7100. 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 3.76μm versus 3.91μm for the D7100). However, it should be noted that the K-3 III is much more recent (by 8 years and 1 month) than the D7100, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. Coming back to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

Unlike the D7100, the K-3 III has the capacity to capture high quality composite images (YESMP) 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 D7100 has a native sensitivity range from ISO 100 to ISO 6400, which can be extended to ISO 50-25600. The corresponding ISO settings for the Pentax K-3 III are ISO 100 to ISO 160000 (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 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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-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 D7100	APS-C	24.0	6000	4000	1080/60p	24.2	13.7	1256	83
2.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
3.		Canon 70D	APS-C	20.0	5472	3648	1080/30p	22.5	11.6	926	68
4.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
5.		Nikon D7500	APS-C	20.7	5568	3712	4K/30p	24.3	14.0	1483	86
6.		Nikon D500	APS-C	20.7	5568	3712	4K/30p	24.0	14.0	1324	83
7.		Nikon D7200	APS-C	24.0	6000	4000	1080/60p	24.5	14.6	1333	87
8.		Nikon D750	Full Frame	24.2	6016	4016	1080/60p	24.8	14.5	2956	93
9.		Nikon D3300	APS-C	24.0	6000	4000	1080/60p	24.3	12.8	1385	82
10.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
11.		Nikon D600	Full Frame	24.2	6016	4016	1080/30p	25.1	14.2	2980	94
12.		Nikon D7000	APS-C	16.1	4928	3264	1080/24p	23.5	13.9	1167	80
13.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
14.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
15.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
16.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
17.		Sony RX10	1-inch	20.0	5472	3648	1080/60p	22.9	12.6	474	69
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. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the K-3 III provides a better video resolution than the D7100. It can shoot movie footage at 4K/30p, while the Nikon is limited to 1080/60p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The D7100 and the K-3 III 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 viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the K-3 III has a higher magnification than the one of the D7100 (0.70x vs 0.63x), 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 D7100 and Pentax K-3 III 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 D7100	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
2.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
3.		Canon 70D	optical	Y	3.0 / 1040	swivel	Y	1/8000s	7.0/s	Y	n
4.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
5.		Nikon D7500	optical	Y	3.2 / 922	tilting	Y	1/8000s	8.0/s	Y	n
6.		Nikon D500	optical	Y	3.2 / 2359	tilting	Y	1/8000s	10.0/s	n	n
7.		Nikon D7200	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
8.		Nikon D750	optical	Y	3.2 / 1229	tilting	n	1/4000s	6.0/s	Y	n
9.		Nikon D3300	optical	n	3.0 / 921	fixed	n	1/4000s	5.0/s	Y	n
10.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
11.		Nikon D600	optical	Y	3.0 / 921	fixed	n	1/4000s	5.5/s	Y	n
12.		Nikon D7000	optical	Y	3.0 / 921	fixed	n	1/8000s	6.0/s	Y	n
13.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
14.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
15.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
16.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
17.		Sony RX10	1440	Y	3.0 / 1229	tilting	n	1/3200s	10.0/s	Y	Y
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 D7100 has one, while the K-3 III does not. While the built-in flash of the D7100 is not very powerful, it can at times be useful as a fill-in light.

The Nikon D7100 and the Pentax K-3 III both have 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 D7100 and the K-3 III write their files to SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. The K-3 III supports UHS-II cards (on its first slot), while the D7100 can use UHS-I 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 D7100 and Pentax K-3 III 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 D7100	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
2.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
3.		Canon 70D	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
4.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
5.		Nikon D7500	Y	stereo / mono	Y	Y	mini	2.0	Y	-	Y
6.		Nikon D500	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
7.		Nikon D7200	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
8.		Nikon D750	Y	stereo / mono	Y	Y	mini	2.0	Y	-	-
9.		Nikon D3300	Y	mono / mono	Y	-	mini	2.0	-	-	-
10.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
11.		Nikon D600	Y	mono / mono	Y	Y	mini	2.0	-	-	-
12.		Nikon D7000	Y	mono / mono	Y	-	mini	2.0	-	-	-
13.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
14.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
15.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
16.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
17.		Sony RX10	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-

It is notable that the K-3 III offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the D7100 does not provide wifi capability.

Studio photographers will appreciate that the Pentax K-3 III (unlike the D7100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Travel and landscape photographers will find it useful that the K-3 III has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

The K-3 III is a recent model that features in the current product line-up of Pentax. In contrast, the D7100 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the D7100 was succeeded by the Nikon D7200. Further information on the features and operation of the D7100 and K-3 III can be found, respectively, in the Nikon D7100 Manual (free pdf) or the online Pentax K-3 III Manual.

Review summary

So how do things add up? Which of the two cameras – the Nikon D7100 or the Pentax K-3 III – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Nikon D7100:

• Longer lasting: Can take more shots (950 versus 800) 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 (40 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in February 2013).

Advantages of the Pentax K-3 III:

• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.70x vs 0.63x).
• More detailed LCD: Has a higher resolution rear screen (1620k vs 1229k dots).
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• Faster burst: Shoots at higher frequency (12 vs 6 flaps/sec) to capture the decisive moment.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
• More modern: Reflects 8 years and 1 month of technical progress since the D7100 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the K-3 III is the clear winner of the contest (14 : 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 Nikon D7100 and the Pentax K-3 III 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 specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the D7100 or the K-3 III. 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 where reviews by experts come in. 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.		Nikon D7100	5/5	+ +	..	85/100	4.5/5	4.5/5	Feb 2013	1,199	ebay.com
2.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
3.		Canon 70D	5/5	+ +	..	83/100	4.5/5	5/5	Jul 2013	1,199	ebay.com
4.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	1,899	ebay.com
5.		Nikon D7500	4.5/5	+ +	4.5/5	86/100	5/5	4.5/5	Apr 2017	1,299	amazon.com
6.		Nikon D500	5/5	+ +	4.7/5	91/100	4.5/5	5/5	Jan 2016	1,999	ebay.com
7.		Nikon D7200	4/5	+ +	..	84/100	4.5/5	4.5/5	Mar 2015	1,199	ebay.com
8.		Nikon D750	5/5	+ +	4/5	90/100	4.5/5	4.5/5	Sep 2014	2,299	ebay.com
9.		Nikon D3300	3/5	+	..	77/100	4.5/5	4.5/5	Jan 2014	499	ebay.com
10.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
11.		Nikon D600	4/5	+ +	..	87/100	5/5	4.5/5	Sep 2012	2,099	ebay.com
12.		Nikon D7000	4/5	..	..	80/100	4.5/5	4.5/5	Sep 2010	1,499	ebay.com
13.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
14.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
15.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
16.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
17.		Sony RX10	5/5	+	..	80/100	4.5/5	4.5/5	Oct 2013	1,299	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The assessments were made in relation to similar cameras of the same technological generation. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date 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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Check K-3 III price at
amazon.com

Other camera comparisons

Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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