Pentax K-3 II vs Nikon D810

The Pentax K-3 II and the Nikon D810 are two digital cameras that were announced, respectively, in April 2015 and June 2014. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (K-3 II) and a full frame (D810) sensor. The Pentax has a resolution of 24.1 megapixels, whereas the Nikon provides 36.2 MP.

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

Headline Specifications

Pentax K-3 II		Nikon D810
Digital single lens reflex		Digital single lens reflex
Pentax K mount lenses		Nikon F mount lenses
24.1 MP – APS-C sensor		36.2 MP – Full Frame sensor
1080/60i Video		1080/60p Video
ISO 100-51,200		ISO 64-12,800 (32 - 51,200)
Optical viewfinder		Optical viewfinder
3.2" LCD – 1037k dots		3.2" LCD – 1229k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
8.3 shutter flaps per second		5 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		Weathersealed body
720 shots per battery charge		1200 shots per battery charge
131 x 100 x 77 mm, 800 g		146 x 123 x 82 mm, 980 g

Check K-3 II offers at
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Check D810 offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-3 II and the Nikon D810? 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 Pentax K-3 II and the Nikon D810 are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side are shown. All width, height and depth dimensions are rounded to the nearest millimeter.

The K-3 II can be obtained in two different colors (black, silver), while the D810 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 D810 is notably larger (37 percent) than the Pentax K-3 II. Moreover, the D810 is markedly heavier (23 percent) than the K-3 II. 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 K-3 II gets 720 shots out of its Pentax D-LI90 battery, while the D810 can take 1200 images on a single charge of its Nikon EN-EL15 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 (USD)	Street Price
1.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
2.		Nikon D810	146 mm	123 mm	82 mm	980 g	1200	Y	Jun 2014	3,299	ebay.com
3.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
4.		Nikon D850	146 mm	124 mm	79 mm	1005 g	1840	Y	Jul 2017	3,299	amazon.com
5.		Nikon D7200	136 mm	107 mm	76 mm	765 g	1110	Y	Mar 2015	1,199	ebay.com
6.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
7.		Nikon D800	146 mm	123 mm	82 mm	1000 g	900	Y	Feb 2012	2,999	ebay.com
8.		Nikon D800E	146 mm	123 mm	82 mm	1000 g	900	Y	Feb 2012	3,299	ebay.com
9.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
10.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
11.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
12.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	ebay.com
13.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	749	ebay.com
14.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
15.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	1,099	ebay.com
16.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	1,099	ebay.com
17.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	1,199	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The K-3 II was launched at a markedly lower price (by 67 percent) than the D810, 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. 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.

Of the two cameras under consideration, the Pentax K-3 II features an APS-C sensor and the Nikon D810 a full frame sensor. The sensor area in the D810 is 135 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 36.2MP, the D810 offers a higher resolution than the K-3 II (24.1MP), but the D810 nevertheless has larger individual pixels (pixel pitch of 4.88μm versus 3.90μm for the K-3 II) due to its larger sensor. However, the K-3 II is a somewhat more recent model (by 9 months) than the D810, and its sensor might 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 neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

The resolution advantage of the Nikon D810 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the D810 for good quality output (200 dots per inch) amounts to 36.8 x 24.6 inches or 93.5 x 62.4 cm, for very good quality (250 dpi) 29.4 x 19.6 inches or 74.8 x 49.9 cm, and for excellent quality (300 dpi) 24.5 x 16.4 inches or 62.3 x 41.6 cm. The corresponding values for the Pentax K-3 II are 30.1 x 20 inches or 76.4 x 50.8 cm for good quality, 24.1 x 16 inches or 61.1 x 40.6 cm for very good quality, and 20.1 x 13.3 inches or 50.9 x 33.9 cm for excellent quality prints.

Unlike the D810, the K-3 II 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 Pentax K-3 II has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Nikon D810 are ISO 64 to ISO 12800, with the possibility to increase the ISO range to 32-51200.

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 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. Of the two cameras under consideration, the D810 offers substantially better image quality than the K-3 II (overall score 17 points higher). The advantage is based on 2.1 bits higher color depth, 1.2 EV in additional dynamic range, and 1.4 stops in additional low light sensitivity. 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.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
2.		Nikon D810	Full Frame	36.2	7360	4912	1080/60p	25.7	14.8	2853	97
3.		Canon 5DS	Full Frame	50.3	8688	5792	1080/30p	24.7	12.4	2381	87
4.		Nikon D850	Full Frame	45.4	8256	5504	4K/30p	26.4	14.8	2660	100
5.		Nikon D7200	APS-C	24.0	6000	4000	1080/60p	24.5	14.6	1333	87
6.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
7.		Nikon D800	Full Frame	36.2	7360	4912	1080/30p	25.3	14.4	2853	95
8.		Nikon D800E	Full Frame	36.2	7360	4912	1080/30p	25.6	14.3	2979	96
9.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
10.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
11.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
12.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
13.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
14.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
15.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
16.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
17.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the D810 provides a faster frame rate than the K-3 II. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The K-3 II and the D810 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 D810 has a higher magnification than the one of the K-3 II (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 Pentax K-3 II and Nikon D810 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.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
2.		Nikon D810	optical	Y	3.2 / 1229	fixed	n	1/8000s	5.0/s	Y	n
3.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
4.		Nikon D850	optical	Y	3.2 / 2359	tilting	Y	1/8000s	9.0/s	n	n
5.		Nikon D7200	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
6.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
7.		Nikon D800	optical	Y	3.2 / 921	fixed	n	1/8000s	4.0/s	Y	n
8.		Nikon D800E	optical	Y	3.2 / 921	fixed	n	1/8000s	4.0/s	Y	n
9.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
10.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
11.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
12.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
13.		Pentax K-S1	optical	n	3.0 / 921	fixed	n	1/6000s	5.4/s	Y	Y
14.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
15.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
16.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
17.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/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 II and the D810 is in-body image stabilization (IBIS). The K-3 II reduces the risk of handshake-induced blur with all attached lenses, while the D810 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The Pentax K-3 II and the Nikon D810 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 K-3 II writes its imaging data to SDXC cards, while the D810 uses Compact Flash or SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.

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 Pentax K-3 II and Nikon D810 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.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
2.		Nikon D810	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
3.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
4.		Nikon D850	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
5.		Nikon D7200	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
6.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
7.		Nikon D800	Y	mono / mono	Y	Y	mini	3.0	-	-	-
8.		Nikon D800E	Y	mono / mono	Y	Y	mini	3.0	-	-	-
9.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
10.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
11.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
12.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
13.		Pentax K-S1	Y	stereo / mono	-	-	micro	2.0	-	-	-
14.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
17.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-

It is notable that the D810 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the K-3 II does not provide wifi capability.

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 II has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

Both the K-3 II and the D810 have been discontinued, but can regularly be found used on ebay. The D810 was replaced by the Nikon D850, while the K-3 II was followed by the Pentax K-3 III. Further information on the features and operation of the K-3 II and D810 can be found, respectively, in the Pentax K-3 II Manual (free pdf) or the online Nikon D810 Manual.

Review summary

So what is the bottom line? Is the Pentax K-3 II better than the Nikon D810 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Pentax K-3 II:

• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Faster burst: Shoots at higher frequency (8.3 vs 5 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (131x100mm vs 146x123mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 180g or 18 percent) and hence easier to carry around.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• More affordable: Was introduced into a lower priced category (67 percent cheaper at launch).
• More modern: Is somewhat more recent (announced 9 months after the D810).

Arguments in favor of the Nikon D810:

• More detail: Has more megapixels (36.2 vs 24.1MP), which boosts linear resolution by 22%.
• Better image quality: Scores substantially higher (17 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.1 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1.2 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (1.4 stops ISO advantage).
• Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.70x vs 0.63x).
• More detailed LCD: Has a higher resolution rear screen (1229k vs 1037k dots).
• Longer lasting: Gets more shots (1200 versus 720) out of a single battery charge.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• More heavily discounted: Has been on the market for longer (launched in June 2014).

If the count of individual advantages (bullet points above) is taken as a guide, the D810 is the clear winner of the contest (12 : 8 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision 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 Pentax K-3 II and the Nikon D810 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 says little about, for example, the shooting experience and imaging performance of the K-3 II and the D810 in practical situations. 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 (USD)	Street Price
1.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
2.		Nikon D810	5/5	..	5/5	86/100	5/5	4.5/5	Jun 2014	3,299	ebay.com
3.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	3,699	ebay.com
4.		Nikon D850	4.5/5	+ +	5/5	89/100	4.5/5	5/5	Jul 2017	3,299	amazon.com
5.		Nikon D7200	4/5	+ +	..	84/100	4.5/5	4.5/5	Mar 2015	1,199	ebay.com
6.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
7.		Nikon D800	5/5	+ +	..	82/100	5/5	5/5	Feb 2012	2,999	ebay.com
8.		Nikon D800E	..	..	..	84/100	5/5	5/5	Feb 2012	3,299	ebay.com
9.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
10.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
11.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
12.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
13.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	749	ebay.com
14.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
15.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	1,099	ebay.com
16.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	1,099	ebay.com
17.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	1,199	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, 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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just use the search menu below. 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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