Nikon D3X vs Pentax K-70

The Nikon D3X and the Pentax K-70 are two digital cameras that were revealed to the public, respectively, in December 2008 and June 2016. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a full frame (D3X) and an APS-C (K-70) sensor. The Nikon has a resolution of 24.4 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 D3X		Pentax K-70
Digital single lens reflex		Digital single lens reflex
Nikon F mount lenses		Pentax K mount lenses
24.4 MP – Full Frame sensor		24 MP – APS-C sensor
no Video		1080/60i Video
ISO 100-1,600 (50 - 6,400)		ISO 100-102,400
Optical viewfinder		Optical viewfinder
3.0" LCD – 922k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Swivel screen (not touch-sensitive)
5 shutter flaps per second		6 shutter flaps per second
Lens stabilization only		In-body stabilization
Weathersealed body		Weathersealed body
4400 shots per battery charge		410 shots per battery charge
160 x 157 x 88 mm, 1260 g		126 x 93 x 74 mm, 688 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D3X 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 D3X and the Pentax K-70. 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-70 can be obtained in two different colors (black, silver), while the D3X 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-70 is considerably smaller (53 percent) than the Nikon D3X. Moreover, the K-70 is substantially lighter (45 percent) than the D3X. 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 D3X gets 4400 shots out of its Nikon EN-EL4a battery, while the K-70 can take 410 images on a single charge of its Pentax D-LI109 power pack. As can be seen in the images above, the D3X has a battery grip built in. This facilitates image-taking in portrait orientation and gives it additional battery power.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras 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 D3X	160 mm	157 mm	88 mm	1260 g	4400	Y	Dec 2008	7,999	ebay.com
2.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
3.		Canon 1Ds Mark III	150 mm	160 mm	80 mm	1385 g	1800	Y	Aug 2007	7,999	ebay.com
4.		Nikon D5	160 mm	159 mm	92 mm	1415 g	3780	Y	Jan 2016	6,499	ebay.com
5.		Nikon D4S	160 mm	157 mm	91 mm	1350 g	3020	Y	Feb 2014	6,499	ebay.com
6.		Nikon D750	141 mm	113 mm	78 mm	750 g	1230	Y	Sep 2014	2,299	ebay.com
7.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
8.		Nikon D4	160 mm	157 mm	91 mm	1340 g	2600	Y	Jan 2012	5,999	ebay.com
9.		Nikon D600	141 mm	113 mm	82 mm	850 g	900	Y	Sep 2012	2,099	ebay.com
10.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
11.		Nikon D700	147 mm	123 mm	77 mm	1074 g	1000	Y	Jul 2008	2,999	ebay.com
12.		Nikon D3	160 mm	157 mm	88 mm	1300 g	4300	Y	Aug 2007	4,999	ebay.com
13.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
14.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	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-50	130 mm	97 mm	71 mm	650 g	410	Y	Jun 2013	599	ebay.com
17.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	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 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 K-70 was launched at a markedly lower price (by 92 percent) than the D3X, 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Nikon D3X features a full frame sensor and the Pentax K-70 an APS-C sensor. The sensor area in the K-70 is 57 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.

With 24.4MP, the D3X offers a slightly higher resolution than the K-70 (24MP), but the D3X nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 3.91μm for the K-70) due to its larger sensor. However, the K-70 is a much more recent model (by 7 years and 6 months) than the D3X, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. 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 K-70 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

Unlike the D3X, 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 D3X has a native sensitivity range from ISO 100 to ISO 1600, which can be extended to ISO 50-6400. 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.

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 D3X	Full Frame	24.4	6048	4032	none	24.7	13.7	1992	88
2.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
3.		Canon 1Ds Mark III	Full Frame	21.0	5616	3744	none	24.0	12.0	1663	80
4.		Nikon D5	Full Frame	20.7	5588	3712	4K/30p	25.1	12.3	2343	88
5.		Nikon D4S	Full Frame	16.2	4928	3280	1080/60p	24.4	13.3	3074	89
6.		Nikon D750	Full Frame	24.2	6016	4016	1080/60p	24.8	14.5	2956	93
7.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
8.		Nikon D4	Full Frame	16.2	4928	3280	1080/30p	24.7	13.1	2965	89
9.		Nikon D600	Full Frame	24.2	6016	4016	1080/30p	25.1	14.2	2980	94
10.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
11.		Nikon D700	Full Frame	12.1	4256	2832	none	23.5	12.2	2303	80
12.		Nikon D3	Full Frame	12.1	4256	2832	none	23.5	12.2	2290	81
13.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
14.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
15.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
16.		Pentax K-50	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1120	79
17.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
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. The K-70 indeed provides for movie recording, while the D3X does not. The highest resolution format that the K-70 can use is 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The D3X 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 viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the D3X has a higher magnification than the one of the K-70 (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 table below summarizes some of the other core capabilities of the Nikon D3X 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 D3X	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	n
2.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
3.		Canon 1Ds Mark III	optical	Y	3.0 / 230	fixed	n	1/8000s	5.0/s	n	n
4.		Nikon D5	optical	Y	3.2 / 2359	fixed	Y	1/8000s	14.0/s	n	n
5.		Nikon D4S	optical	Y	3.2 / 921	fixed	n	1/8000s	11.0/s	n	n
6.		Nikon D750	optical	Y	3.2 / 1229	tilting	n	1/4000s	6.0/s	Y	n
7.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
8.		Nikon D4	optical	Y	3.2 / 921	fixed	n	1/8000s	11.0/s	n	n
9.		Nikon D600	optical	Y	3.0 / 921	fixed	n	1/4000s	5.5/s	Y	n
10.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
11.		Nikon D700	optical	Y	3.0 / 922	fixed	n	1/8000s	8.0/s	Y	n
12.		Nikon D3	optical	Y	3.0 / 922	fixed	n	1/8000s	11.0/s	n	n
13.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
14.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/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-50	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
17.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the D3X, but is missing on the K-70 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The Nikon D3X and the Pentax K-70 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 D3X writes its imaging data to Compact Flash cards, while the K-70 uses SDXC cards. The D3X features dual card slots, which can be very useful in case a memory card fails. In contrast, the K-70 only has one slot.

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 D3X 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 D3X	Y	- / -	-	-	mini	2.0	-	-	-
2.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
3.		Canon 1Ds Mark III	Y	mono / -	-	-	-	2.0	-	-	-
4.		Nikon D5	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
5.		Nikon D4S	Y	mono / mono	Y	Y	mini	2.0	-	-	-
6.		Nikon D750	Y	stereo / mono	Y	Y	mini	2.0	Y	-	-
7.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
8.		Nikon D4	Y	mono / mono	Y	Y	micro	2.0	-	-	-
9.		Nikon D600	Y	mono / mono	Y	Y	mini	2.0	-	-	-
10.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Nikon D700	Y	- / -	-	-	mini	2.0	-	-	-
12.		Nikon D3	Y	- / -	-	-	mini	2.0	-	-	-
13.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
14.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
15.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
16.		Pentax K-50	Y	mono / mono	-	-	micro	2.0	-	-	-
17.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-

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 D3X does not provide wifi capability.

Studio photographers will appreciate that the Nikon D3X (unlike the K-70) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the D3X and the K-70 have been discontinued, but can regularly be found used on ebay. Neither of the two has a direct successor, so they represent the end of the respective camera lines from Nikon and Pentax. Further information on the features and operation of the D3X and K-70 can be found, respectively, in the Nikon D3X Manual (free pdf) or the online Pentax K-70 Manual.

Review summary

So what conclusions can be drawn? Which of the two cameras – the Nikon D3X or the Pentax K-70 – 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.

Advantages of the Nikon D3X:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.70x vs 0.63x).
• Easier setting verification: Features an LCD display on top to control shooting parameters.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/6000s) to freeze action.
• More portrait friendly: Features an integrated vertical grip for easier portrait shooting.
• Longer lasting: Can take more shots (4400 versus 410) on a single battery charge.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More heavily discounted: Has been available for much longer (launched in December 2008).

Reasons to prefer the Pentax K-70:

• 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.
• Broader imaging potential: Can capture not only stills but also 1080/60i video.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• 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 burst: Shoots at higher frequency (6 vs 5 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (126x93mm vs 160x157mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 572g or 45 percent) and is thus easier to take along.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• 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 affordable: Was introduced into a lower priced category (92 percent cheaper at launch).
• More modern: Reflects 7 years and 6 months of technical progress since the D3X launch.

If the number of relative strengths (bullet points above) is taken as a guide, the K-70 is the clear winner of the contest (14 : 9 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 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 D3X 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 says little about, for example, the shooting experience and imaging performance of the D3X and the K-70 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 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 D3X	..	..	..	86/100	4/5	5/5	Dec 2008	7,999	ebay.com
2.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
3.		Canon 1Ds Mark III	..	..	..	+ +	4.5/5	..	Aug 2007	7,999	ebay.com
4.		Nikon D5	..	..	4/5	89/100	4.5/5	5/5	Jan 2016	6,499	ebay.com
5.		Nikon D4S	5/5	..	..	..	4.5/5	4.5/5	Feb 2014	6,499	ebay.com
6.		Nikon D750	5/5	+ +	4/5	90/100	4.5/5	4.5/5	Sep 2014	2,299	ebay.com
7.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
8.		Nikon D4	..	..	..	..	4.5/5	4.5/5	Jan 2012	5,999	ebay.com
9.		Nikon D600	4/5	+ +	..	87/100	5/5	4.5/5	Sep 2012	2,099	ebay.com
10.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
11.		Nikon D700	..	89/100	..	+ +	4.5/5	4.5/5	Jul 2008	2,999	ebay.com
12.		Nikon D3	..	..	..	+ +	5/5	4.5/5	Aug 2007	4,999	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-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
15.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
16.		Pentax K-50	5/5	..	..	..	5/5	4.5/5	Jun 2013	599	ebay.com
17.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	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. A score, therefore, has to be seen in close connection to the price and market introduction time 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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