Nikon D300S vs Pentax K-3 III

The Nikon D300S and the Pentax K-3 III are two enthusiast cameras that were announced, respectively, in July 2009 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 12.2 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 D300S		Pentax K-3 III
Digital single lens reflex		Digital single lens reflex
Nikon F mount lenses		Pentax K mount lenses
12.2 MP – APS-C sensor		25.6 MP – APS-C sensor
720/24p Video		4K/30p Video
ISO 200-3,200 (100 - 6,400)		ISO 100-160,000
Optical viewfinder		Optical viewfinder
3.0" LCD – 920k dots		3.2" LCD – 1620k dots
Fixed screen (not touch-sensitive)		Fixed touchscreen
7 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
147 x 115 x 81 mm, 938 g		135 x 104 x 74 mm, 820 g

Check D300S 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 D300S 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 D300S 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 views from the front, the top, and the rear side are shown. All width, height and depth measures are rounded to the nearest millimeter.

The K-3 III can be obtained in two different colors (black, silver), while the D300S 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 notably smaller (17 percent) than the Nikon D300S. Moreover, the K-3 III is markedly lighter (13 percent) than the D300S. 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 D300S gets 950 shots out of its Nikon EN-EL3e battery, while the K-3 III can take 800 images on a single charge of its Pentax D-LI90 power pack.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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	Street Price
1.		Nikon D300S	147 mm	115 mm	81 mm	938 g	950	Y	Jul 2009	US$ 1 799	ebay.com
2.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	US$ 1 999	amazon.com
3.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	US$ 1 899	ebay.com
4.		Nikon D2X	158 mm	150 mm	86 mm	1252 g	3800	Y	Sep 2004	US$ 4 999	ebay.com
5.		Nikon D2Xs	158 mm	150 mm	86 mm	1252 g	3800	Y	Jun 2006	US$ 4 699	ebay.com
6.		Nikon D60	126 mm	94 mm	64 mm	522 g	500	n	Jan 2008	US$ 629	ebay.com
7.		Nikon D200	147 mm	113 mm	74 mm	920 g	400	Y	Nov 2005	US$ 1 699	ebay.com
8.		Nikon D300	147 mm	114 mm	74 mm	925 g	1000	Y	Aug 2007	US$ 1 799	ebay.com
9.		Nikon D500	147 mm	115 mm	81 mm	860 g	1240	Y	Jan 2016	US$ 1 999	ebay.com
10.		Nikon D700	147 mm	123 mm	77 mm	1074 g	1000	Y	Jul 2008	US$ 2 999	ebay.com
11.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	US$ 599	ebay.com
12.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	US$ 749	ebay.com
13.		Nikon D7000	132 mm	105 mm	77 mm	780 g	1050	Y	Sep 2010	US$ 1 499	ebay.com
14.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	US$ 1 299	ebay.com
15.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	US$ 1 099	ebay.com
16.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	US$ 649	ebay.com
17.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	US$ 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 naturally be influenced heavily by the price. 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 D300S was somewhat cheaper (by 10 percent) than the K-3 III at launch, but both cameras fall into the same price category. 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. 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. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units in a sensor of the same technological generation. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better 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-3 III is 3 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 higher resolution of 25.6 megapixels, compared with 12.2 MP of the D300S. 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 5.53μm for the D300S). However, it should be noted that the K-3 III is much more recent (by 11 years and 8 months) than the D300S, 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 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 D300S are 21.4 x 14.2 inches or 54.5 x 36.2 cm for good quality, 17.2 x 11.4 inches or 43.6 x 28.9 cm for very good quality, and 14.3 x 9.5 inches or 36.3 x 24.1 cm for excellent quality prints.

Unlike the D300S, 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 D300S has a native sensitivity range from ISO 200 to ISO 3200, which can be extended to ISO 100-6400. 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 is based on lab testing and assigns an overall score to each camera sensor, as well as ratings for dynamic range ("DXO Landscape"), color depth ("DXO Portrait"), and low-light sensitivity ("DXO Sports"). 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 D300S	APS-C	12.2	4288	2848	720/24p	22.5	12.2	787	70
2.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
3.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
4.		Nikon D2X	APS-C	12.2	4288	2848	none	22.1	10.9	476	59
5.		Nikon D2Xs	APS-C	12.2	4288	2848	none	22.2	10.9	489	59
6.		Nikon D60	APS-C	10.0	3872	2592	none	22.5	11.4	562	65
7.		Nikon D200	APS-C	10.0	3872	2592	none	22.3	11.5	583	64
8.		Nikon D300	APS-C	12.2	4288	2848	none	22.1	12.0	679	67
9.		Nikon D500	APS-C	20.7	5568	3712	4K/30p	24.0	14.0	1324	83
10.		Nikon D700	Full Frame	12.1	4256	2832	none	23.5	12.2	2303	80
11.		Nikon D3100	APS-C	14.2	4608	3072	1080/24p	22.5	11.3	919	67
12.		Nikon D5000	APS-C	12.2	4288	2848	720/24p	22.7	12.5	868	72
13.		Nikon D7000	APS-C	16.1	4928	3264	1080/24p	23.5	13.9	1167	80
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. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the K-3 III provides a better video resolution than the D300S. It can shoot movie footage at 4K/30p, while the Nikon is limited to 720/24p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The D300S 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 D300S (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 following table reports on some other key feature differences and similarities of the Nikon D300S, 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 D300S	optical	Y	3.0 / 920	fixed	n	1/8000s	7.0/s	Y	n
2.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
3.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
4.		Nikon D2X	optical	Y	2.5 / 235	fixed	n	1/8000s	5.0/s	n	n
5.		Nikon D2Xs	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	n	n
6.		Nikon D60	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
7.		Nikon D200	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
8.		Nikon D300	optical	Y	3.0 / 922	fixed	n	1/8000s	6.0/s	Y	n
9.		Nikon D500	optical	Y	3.2 / 2359	tilting	Y	1/8000s	10.0/s	n	n
10.		Nikon D700	optical	Y	3.0 / 922	fixed	n	1/8000s	8.0/s	Y	n
11.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
12.		Nikon D5000	optical	n	2.7 / 230	full-flex	n	1/4000s	4.0/s	Y	n
13.		Nikon D7000	optical	Y	3.0 / 921	fixed	n	1/8000s	6.0/s	Y	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 difference between the cameras concerns the presence of an on-board flash. The D300S has one, while the K-3 III does not. While the built-in flash of the D300S is not very powerful, it can at times be useful as a fill-in light.

The Nikon D300S 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 D300S writes its imaging data to Compact Flash or SDXC 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. The K-3 III supports UHS-II cards on its first slot and UHS-I on its second one, while the D300S 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 D300S 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 D300S	Y	stereo / mono	Y	-	mini	2.0	-	-	-
2.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
3.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
4.		Nikon D2X	Y	- / -	-	-	-	2.0	-	-	-
5.		Nikon D2Xs	Y	- / -	-	-	-	2.0	-	-	-
6.		Nikon D60	Y	- / -	-	-	-	2.0	-	-	-
7.		Nikon D200	Y	- / -	-	-	-	2.0	-	-	-
8.		Nikon D300	Y	- / -	-	-	mini	2.0	-	-	-
9.		Nikon D500	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
10.		Nikon D700	Y	- / -	-	-	mini	2.0	-	-	-
11.		Nikon D3100	Y	mono / mono	-	-	mini	2.0	-	-	-
12.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-
13.		Nikon D7000	Y	mono / mono	Y	-	mini	2.0	-	-	-
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	-	-

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 D300S 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 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 D300S has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the D300S was succeeded by the Nikon D500. Further information on the features and operation of the D300S and K-3 III can be found, respectively, in the Nikon D300S Manual (free pdf) or the online Pentax K-3 III Manual.

Review summary

So what is the bottom line? Is the Nikon D300S better than the Pentax K-3 III or vice versa? The listing below highlights the relative strengths of the two models.

Arguments in favor of the Nikon D300S:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• 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 heavily discounted: Has been available for much longer (launched in July 2009).

Advantages of the Pentax K-3 III:

• More detail: Has more megapixels (25.6 vs 12.2MP), which boosts linear resolution by 45%.
• 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 definition movie capture (4K/30p vs 720/24p).
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.70x vs 0.63x).
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (1620k vs 920k dots).
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• Faster burst: Shoots at higher frequency (12 vs 7 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (135x104mm vs 147x115mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 118g or 13 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 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.
• Faster buffer clearing: Supports Ultra High Speed (UHS-II and UHS-I) SDXC cards.
• More modern: Reflects 11 years and 8 months of technical progress since the D300S launch.

If the count of relative strengths (bullet points above) is taken as a measure, the K-3 III is the clear winner of the contest (19 : 4 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 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 D300S 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 remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the D300S or the K-3 III. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable.

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	Street Price
1.		Nikon D300S	5/5	+ +	..	82/100	4/5	4.5/5	Jul 2009	US$ 1 799	ebay.com
2.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	US$ 1 999	amazon.com
3.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	US$ 1 899	ebay.com
4.		Nikon D2X	..	..	..	+ +	..	..	Sep 2004	US$ 4 999	ebay.com
5.		Nikon D2Xs	..	..	..	..	..	..	Jun 2006	US$ 4 699	ebay.com
6.		Nikon D60	..	80/100	..	+ +	4/5	4.5/5	Jan 2008	US$ 629	ebay.com
7.		Nikon D200	..	+ +	..	+ +	o	..	Nov 2005	US$ 1 699	ebay.com
8.		Nikon D300	..	+ +	..	+ +	5/5	4.5/5	Aug 2007	US$ 1 799	ebay.com
9.		Nikon D500	5/5	+ +	4.7/5	91/100	4.5/5	5/5	Jan 2016	US$ 1 999	ebay.com
10.		Nikon D700	..	89/100	..	+ +	4.5/5	4.5/5	Jul 2008	US$ 2 999	ebay.com
11.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	US$ 599	ebay.com
12.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	US$ 749	ebay.com
13.		Nikon D7000	4/5	..	..	80/100	4.5/5	4.5/5	Sep 2010	US$ 1 499	ebay.com
14.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	US$ 1 299	ebay.com
15.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	US$ 1 099	ebay.com
16.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	US$ 649	ebay.com
17.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	US$ 1 099	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted 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 comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

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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 a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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