Nikon D6 vs Pentax K-3 III

The Nikon D6 and the Pentax K-3 III are two digital cameras that were announced, respectively, in February 2020 and March 2021. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a full frame (D6) and an APS-C (K-3 III) sensor. The Nikon has a resolution of 20.7 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 D6		Pentax K-3 III
Digital single lens reflex		Digital single lens reflex
Nikon F mount lenses		Pentax K mount lenses
20.7 MP – Full Frame sensor		25.6 MP – APS-C sensor
4K/30p Video		4K/30p Video
ISO 100-102,400 (50 - 3,280,000)		ISO 100-160,000
Optical viewfinder		Optical viewfinder
3.2" LCD – 2359k dots		3.2" LCD – 1620k dots
Fixed touchscreen		Fixed touchscreen
14 shutter flaps per second		12 shutter flaps per second
Lens stabilization only		In-body stabilization
Weathersealed body		Weathersealed body
3580 shots per battery charge		800 shots per battery charge
160 x 163 x 92 mm, 1270 g		135 x 104 x 74 mm, 820 g

Check D6 price at
amazon.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 D6 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 physical size and weight of the Nikon D6 and the Pentax K-3 III are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth dimensions are rounded to the nearest millimeter.

The K-3 III can be obtained in two different colors (black, silver), while the D6 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 considerably smaller (46 percent) than the Nikon D6. Moreover, the K-3 III is substantially lighter (35 percent) than the D6. 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 D6 gets 3580 shots out of its Nikon EN-EL18c battery, while the K-3 III can take 800 images on a single charge of its Pentax D-LI90 power pack. As can be seen in the images above, the D6 has a battery grip built in. This facilitates image-taking in portrait orientation and gives it additional battery power. In order to provide similar functionality for the K-3 III, Pentax provides the D-BG8 vertical grip as an optional accessory (see here on ebay).

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 D6	160 mm	163 mm	92 mm	1270 g	3580	Y	Feb 2020	6,499	amazon.com
2.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
3.		Canon 1D X Mark II	158 mm	168 mm	83 mm	1530 g	1210	Y	Feb 2016	5,999	ebay.com
4.		Canon 1D X Mark III	158 mm	168 mm	83 mm	1440 g	2850	Y	Jan 2020	6,499	amazon.com
5.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	1,899	ebay.com
6.		Nikon D3X	160 mm	157 mm	88 mm	1260 g	4400	Y	Dec 2008	7,999	ebay.com
7.		Nikon D4	160 mm	157 mm	91 mm	1340 g	2600	Y	Jan 2012	5,999	ebay.com
8.		Nikon D4S	160 mm	157 mm	91 mm	1350 g	3020	Y	Feb 2014	6,499	ebay.com
9.		Nikon D5	160 mm	159 mm	92 mm	1415 g	3780	Y	Jan 2016	6,499	ebay.com
10.		Nikon D600	141 mm	113 mm	82 mm	850 g	900	Y	Sep 2012	2,099	ebay.com
11.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
12.		Nikon D750	141 mm	113 mm	78 mm	750 g	1230	Y	Sep 2014	2,299	ebay.com
13.		Nikon D780	144 mm	116 mm	76 mm	840 g	2260	Y	Jan 2020	2,299	amazon.com
14.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	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-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
17.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The K-3 III was launched at a markedly lower price (by 69 percent) than the D6, which puts it into a different market segment. 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 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. 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Nikon D6 features a full frame sensor and the Pentax K-3 III an APS-C sensor. The sensor area in the K-3 III is 58 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.

Despite having a smaller sensor, the K-3 III offers a higher resolution of 25.6 megapixels, compared with 20.7 MP of the D6. 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 6.44μm for the D6). However, it should be noted that the K-3 III is a somewhat more recent model (by 1 year and 1 month) than the D6, and its sensor might have benefitted from technological advances during this time that partly offset its pixel-size disadvantage. Coming back to sensor resolution, it should be mentioned that the K-3 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax K-3 III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-3 III for good quality output (200 dots per inch) amounts to 31 x 20.6 inches or 78.6 x 52.4 cm, for very good quality (250 dpi) 24.8 x 16.5 inches or 62.9 x 41.9 cm, and for excellent quality (300 dpi) 20.6 x 13.8 inches or 52.4 x 35 cm. The corresponding values for the Nikon D6 are 27.8 x 18.6 inches or 70.7 x 47.1 cm for good quality, 22.3 x 14.8 inches or 56.6 x 37.7 cm for very good quality, and 18.6 x 12.4 inches or 47.1 x 31.4 cm for excellent quality prints.

Unlike the D6, 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 D6 has a native sensitivity range from ISO 100 to ISO 102400, which can be extended to ISO 50-3280000. 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.

For many cameras, data on sensor performance has been reported by DXO Mark. This service assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. 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 D6	Full Frame	20.7	5568	3712	4K/30p	25.3	14.3	2886	95
2.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
3.		Canon 1D X Mark II	Full Frame	20.0	5472	3648	4K/60p	24.1	13.5	3207	88
4.		Canon 1D X Mark III	Full Frame	20.0	5472	3648	4K/60p	24.2	14.5	3248	91
5.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
6.		Nikon D3X	Full Frame	24.4	6048	4032	none	24.7	13.7	1992	88
7.		Nikon D4	Full Frame	16.2	4928	3280	1080/30p	24.7	13.1	2965	89
8.		Nikon D4S	Full Frame	16.2	4928	3280	1080/60p	24.4	13.3	3074	89
9.		Nikon D5	Full Frame	20.7	5588	3712	4K/30p	25.1	12.3	2343	88
10.		Nikon D600	Full Frame	24.2	6016	4016	1080/30p	25.1	14.2	2980	94
11.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
12.		Nikon D750	Full Frame	24.2	6016	4016	1080/60p	24.8	14.5	2956	93
13.		Nikon D780	Full Frame	24.3	6048	4024	4K/30p	25.3	14.3	2877	95
14.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
15.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
16.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
17.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
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, and both provide the same movie specifications (4K/30p).

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The D6 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 D6 has a higher magnification than the one of the K-3 III (0.72x vs 0.70x), 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 Nikon D6, the Pentax K-3 III, 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 D6	optical	Y	3.2 / 2359	fixed	Y	1/8000s	14.0/s	n	n
2.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
3.		Canon 1D X Mark II	optical	Y	3.2 / 1620	fixed	Y	1/8000s	16.0/s	n	n
4.		Canon 1D X Mark III	optical	Y	3.2 / 2100	fixed	Y	1/8000s	20.0/s	n	n
5.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
6.		Nikon D3X	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	n
7.		Nikon D4	optical	Y	3.2 / 921	fixed	n	1/8000s	11.0/s	n	n
8.		Nikon D4S	optical	Y	3.2 / 921	fixed	n	1/8000s	11.0/s	n	n
9.		Nikon D5	optical	Y	3.2 / 2359	fixed	Y	1/8000s	14.0/s	n	n
10.		Nikon D600	optical	Y	3.0 / 921	fixed	n	1/4000s	5.5/s	Y	n
11.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
12.		Nikon D750	optical	Y	3.2 / 1229	tilting	n	1/4000s	6.0/s	Y	n
13.		Nikon D780	optical	Y	3.2 / 2359	tilting	Y	1/8000s	12.0/s	n	n
14.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/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-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
17.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the K-3 III and the D6 is in-body image stabilization (IBIS). The K-3 III reduces the risk of handshake-induced blur with all attached lenses, while the D6 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The Nikon D6 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.

The D6 writes its imaging data to CFexpress (type B) or XQD cards, while the K-3 III uses SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails.

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 D6 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 D6	Y	stereo / mono	Y	Y	mini	3.1	Y	-	Y
2.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
3.		Canon 1D X Mark II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
4.		Canon 1D X Mark III	Y	mono / mono	Y	Y	mini	3.1	Y	-	Y
5.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
6.		Nikon D3X	Y	- / -	-	-	mini	2.0	-	-	-
7.		Nikon D4	Y	mono / mono	Y	Y	micro	2.0	-	-	-
8.		Nikon D4S	Y	mono / mono	Y	Y	mini	2.0	-	-	-
9.		Nikon D5	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
10.		Nikon D600	Y	mono / mono	Y	Y	mini	2.0	-	-	-
11.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
12.		Nikon D750	Y	stereo / mono	Y	Y	mini	2.0	Y	-	-
13.		Nikon D780	Y	stereo / mono	Y	Y	mini	3.1	Y	-	Y
14.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
16.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
17.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-

Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.

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.

Both the D6 and the K-3 III are recent models that are part of the current product line-up. The D6 replaced the earlier Nikon D5, while the K-3 III followed on from the Pentax K-3 II. Further information on the features and operation of the D6 and K-3 III can be found, respectively, in the Nikon D6 Manual (free pdf) or the online Pentax K-3 III Manual.

Review summary

So what conclusions can be drawn? Which of the two cameras – the Nikon D6 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 D6:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better image quality: Features bigger pixels on a larger sensor for higher quality imaging.
• Richer colors: The pixel size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger pixels capture a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger pixels means good image quality even under poor lighting.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.72x vs 0.70x).
• More detailed LCD: Has a higher resolution rear screen (2359k vs 1620k dots).
• Faster burst: Shoots at higher frequency (14 vs 12 flaps/sec) to capture the decisive moment.
• More portrait friendly: Features an integrated vertical grip for easier portrait shooting.
• Longer lasting: Can take more shots (3580 versus 800) on a single battery charge.
• More heavily discounted: Has been on the market for longer (launched in February 2020).

Reasons to prefer the Pentax K-3 III:

• More detail: Has more megapixels (25.6 vs 20.7MP), which boosts linear resolution by 11%.
• 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.
• More compact: Is smaller (135x104mm vs 160x163mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 450g or 35 percent) and is thus easier to take along.
• 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 3.1).
• More affordable: Was introduced into a lower priced category (69 percent cheaper at launch).
• More modern: Was introduced somewhat (1 year and 1 month) more recently.

If the number of relative strengths (bullet points above) is taken as a guide, the D6 comes out slightly ahead of the K-3 III (11 : 10 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 D6 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 comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the D6 and the K-3 III in practical situations. 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 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 D6	..	..	4/5	..	4.5/5	4.5/5	Feb 2020	6,499	amazon.com
2.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
3.		Canon 1D X Mark II	..	..	4.5/5	89/100	4.5/5	4.5/5	Feb 2016	5,999	ebay.com
4.		Canon 1D X Mark III	..	+ +	5/5	..	4.5/5	4/5	Jan 2020	6,499	amazon.com
5.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	1,899	ebay.com
6.		Nikon D3X	..	..	..	86/100	4/5	5/5	Dec 2008	7,999	ebay.com
7.		Nikon D4	..	..	..	..	4.5/5	4.5/5	Jan 2012	5,999	ebay.com
8.		Nikon D4S	5/5	..	..	..	4.5/5	4.5/5	Feb 2014	6,499	ebay.com
9.		Nikon D5	..	..	4/5	89/100	4.5/5	5/5	Jan 2016	6,499	ebay.com
10.		Nikon D600	4/5	+ +	..	87/100	5/5	4.5/5	Sep 2012	2,099	ebay.com
11.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
12.		Nikon D750	5/5	+ +	4/5	90/100	4.5/5	4.5/5	Sep 2014	2,299	ebay.com
13.		Nikon D780	5/5	..	5/5	87/100	4.5/5	4.5/5	Jan 2020	2,299	amazon.com
14.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
15.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
16.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
17.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Check D6 price at
amazon.com
Check K-3 III price at
amazon.com

Other camera comparisons

Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just use the search menu below. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.

~

Check D6 price at
amazon.com
Check K-3 III price at
amazon.com

Did you notice an error on this page? If so, please get in touch, so that we can correct the information.