Pentax K-30 vs Sony RX100

The Pentax K-30 and the Sony Cyber-shot DSC-RX100 are two digital cameras that were revealed to the public, respectively, in May 2012 and June 2012. The K-30 is a DSLR, while the RX100 is a fixed lens compact. The cameras are based on an APS-C (K-30) and an one-inch (RX100) sensor. The Pentax has a resolution of 16.1 megapixels, whereas the Sony provides 20 MP.

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

Headline Specifications

Pentax K-30		Sony RX100
Digital single lens reflex		Fixed lens compact camera
Pentax K mount lenses		28-100mm f/1.8-4.9
16.1 MP – APS-C sensor		20 MP – 1" sensor
1080/30p Video		1080/60p Video
ISO 100-12,800 (100 - 25,600)		ISO 100-6,400 (100 - 25,600)
Optical viewfinder		No viewfinder, LCD framing
3.0" LCD – 921k dots		3.0" LCD – 1229k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
6 shutter flaps per second		10 shutter flaps per second
In-body stabilization		Lens-based stabilization
Weathersealed body		not weather sealed
410 shots per battery charge		330 shots per battery charge
130 x 97 x 71 mm, 650 g		102 x 58 x 36 mm, 240 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-30 and the Sony Cyber-shot DSC-RX100? 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 Pentax K-30 and the Sony RX100. 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-30 can be obtained in seven different colors (black, silver, blue, red, yellow, green, white), while the RX100 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 Sony RX100 is considerably smaller (53 percent) than the Pentax K-30. It is worth mentioning in this context that the K-30 is splash and dust resistant, while the RX100 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the RX100 has a lens built in, whereas the K-30 is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.

Concerning battery life, the K-30 gets 410 shots out of its Pentax D-LI109 battery, while the RX100 can take 330 images on a single charge of its Sony NP-BX1 power pack. The power pack in the RX100 can be charged via the USB port, which can be very convenient when travelling.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. In case you want to display and compare another camera duo, you can use the CAM-parator app to select your camera combination among a large number of options.

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-30	130 mm	97 mm	71 mm	650 g	410	Y	May 2012	849	ebay.com
2.		Sony RX100	102 mm	58 mm	36 mm	240 g	330	n	Jun 2012	649	ebay.com
3.		Canon G9 X Mark II	98 mm	58 mm	31 mm	206 g	235	n	Jan 2017	529	ebay.com
4.		Canon G9 X	98 mm	58 mm	31 mm	209 g	220	n	Oct 2015	529	ebay.com
5.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
6.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	ebay.com
7.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
8.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	749	ebay.com
9.		Pentax K-50	130 mm	97 mm	71 mm	650 g	410	Y	Jun 2013	599	ebay.com
10.		Pentax K-500	130 mm	97 mm	71 mm	646 g	710	n	Jun 2013	549	ebay.com
11.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
12.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	1,099	ebay.com
13.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	1,099	ebay.com
14.		Sony RX100 III	102 mm	58 mm	41 mm	290 g	320	n	May 2014	799	ebay.com
15.		Sony RX10	129 mm	88 mm	102 mm	813 g	420	Y	Oct 2013	1,299	ebay.com
16.		Sony RX100 II	102 mm	58 mm	38 mm	281 g	350	n	Jun 2013	749	ebay.com
17.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The RX100 was launched at a lower price than the K-30, despite having a lens built in. 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. 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 Pentax K-30 features an APS-C sensor and the Sony RX100 an one-inch sensor. The sensor area in the RX100 is 69 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 2.7. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Despite having a smaller sensor, the RX100 offers a higher resolution of 20 megapixels, compared with 16.1 MP of the K-30. 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 2.41μm versus 4.79μm for the K-30). It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation.

The resolution advantage of the Sony RX100 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the RX100 for good quality output (200 dots per inch) amounts to 27.4 x 18.2 inches or 69.5 x 46.3 cm, for very good quality (250 dpi) 21.9 x 14.6 inches or 55.6 x 37.1 cm, and for excellent quality (300 dpi) 18.2 x 12.2 inches or 46.3 x 30.9 cm. The corresponding values for the Pentax K-30 are 24.6 x 16.3 inches or 62.6 x 41.5 cm for good quality, 19.7 x 13.1 inches or 50.1 x 33.2 cm for very good quality, and 16.4 x 10.9 inches or 41.7 x 27.6 cm for excellent quality prints.

The Pentax K-30 has a native sensitivity range from ISO 100 to ISO 12800, which can be extended to ISO 100-25600. The corresponding ISO settings for the Sony Cyber-shot DSC-RX100 are ISO 100 to ISO 6400, with the possibility to increase the ISO range to 100-25600.

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. Of the two cameras under review, the K-30 provides substantially higher image quality than the RX100, with an overall score that is 13 points higher. This advantage is based on 1.1 bits higher color depth, 0.6 EV in additional dynamic range, and 1.5 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-30	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1129	79
2.		Sony RX100	1-inch	20.0	5472	3648	1080/60p	22.6	12.4	390	66
3.		Canon G9 X Mark II	1-inch	20.0	5472	3648	1080/60p	21.9	12.5	522	65
4.		Canon G9 X	1-inch	20.0	5472	3648	1080/60p	21.5	12.3	495	63
5.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
6.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
7.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
8.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
9.		Pentax K-50	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1120	79
10.		Pentax K-500	APS-C	16.1	4928	3264	1080/30p	23.7	13.1	1087	79
11.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
12.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
13.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
14.		Sony RX100 III	1-inch	20.0	5472	3648	1080/60p	22.4	12.3	495	67
15.		Sony RX10	1-inch	20.0	5472	3648	1080/60p	22.9	12.6	474	69
16.		Sony RX100 II	1-inch	20.0	5472	3648	1080/60p	22.5	12.4	483	67
17.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
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. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the RX100 provides a faster frame rate than the K-30. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the K-30 has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the RX100 relies on live view and the rear LCD for framing. The adjacent table lists some of the other core features of the Pentax K-30 and Sony RX100 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-30	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
2.		Sony RX100	none	n	3.0 / 1229	fixed	n	1/2000s	10.0/s	Y	Y
3.		Canon G9 X Mark II	none	n	3.0 / 1040	fixed	Y	1/2000s	8.2/s	Y	Y
4.		Canon G9 X	none	n	3.0 / 1040	fixed	Y	1/2000s	6.0/s	Y	Y
5.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
6.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
7.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
8.		Pentax K-S1	optical	n	3.0 / 921	fixed	n	1/6000s	5.4/s	Y	Y
9.		Pentax K-50	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
10.		Pentax K-500	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
11.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
12.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
13.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
14.		Sony RX100 III	1440	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
15.		Sony RX10	1440	Y	3.0 / 1229	tilting	n	1/3200s	10.0/s	Y	Y
16.		Sony RX100 II	optional	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
17.		Sony A77	2359	Y	3.0 / 921	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.

The K-30 writes its imaging data to SDXC cards, while the RX100 uses SDXC or Memory Stick PRO Duo 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 Pentax K-30 and Sony Cyber-shot DSC-RX100 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-30	Y	mono / mono	-	-	-	2.0	-	-	-
2.		Sony RX100	-	stereo / mono	-	-	micro	2.0	-	-	-
3.		Canon G9 X Mark II	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
4.		Canon G9 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
5.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
6.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
7.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
8.		Pentax K-S1	Y	stereo / mono	-	-	micro	2.0	-	-	-
9.		Pentax K-50	Y	mono / mono	-	-	micro	2.0	-	-	-
10.		Pentax K-500	Y	mono / mono	-	-	-	2.0	-	-	-
11.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
12.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
13.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
14.		Sony RX100 III	-	stereo / mono	-	-	micro	2.0	Y	Y	-
15.		Sony RX10	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony RX100 II	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
17.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-

It is notable that the K-30 has a hotshoe, while the RX100 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.

Both the K-30 and the RX100 have been discontinued, but can regularly be found used on ebay. The K-30 was replaced by the Pentax K-50, while the RX100 was followed by the Sony RX100 II. Further information on the features and operation of the K-30 and RX100 can be found, respectively, in the Pentax K-30 Manual (free pdf) or the online Sony RX100 Manual.

Review summary

So what is the bottom line? Is the Pentax K-30 better than the Sony RX100 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Pentax K-30:

• Better image quality: Scores substantially higher (13 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (1.1 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (0.6 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (1.5 stops ISO advantage).
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Faster shutter: Has higher mechanical shutter speed (1/6000s vs 1/2000s) to freeze action.
• More flexible: Can take a variety of interchangeable lenses, including specialty optics.
• Longer lasting: Can take more shots (410 versus 330) on a single battery charge.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.

Advantages of the Sony Cyber-shot DSC-RX100:

• More detail: Has more megapixels (20 vs 16.1MP), which boosts linear resolution by 11%.
• Better video: Provides higher movie framerates (1080/60p versus 1080/30p).
• More detailed LCD: Has a higher resolution rear screen (1229k vs 921k dots).
• Faster burst: Shoots at higher frequency (10 vs 6 flaps/sec) to capture the decisive moment.
• Ready to shoot: Comes with an integrated lens, while the K-30 requires a separate lens.
• More compact: Is smaller (102x58mm vs 130x97mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight even though it has a lens built in (unlike the K-30).
• Easier travel charging: Can be conveniently charged via its USB port.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.

If the count of relative strengths (bullet points above) is taken as a measure, the K-30 comes out slightly ahead of the RX100 (10 : 9 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 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 Pentax K-30 and the Sony RX100 place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Travel-Zoom Camera listings 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 remains incomplete and does no justice, for example, to the way the K-30 or the RX100 perform in practice. 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 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-30	4/5	..	..	78/100	4.5/5	4.5/5	May 2012	849	ebay.com
2.		Sony RX100	5/5	+ +	..	78/100	4/5	5/5	Jun 2012	649	ebay.com
3.		Canon G9 X Mark II	4/5	..	4/5	75/100	4.5/5	4.5/5	Jan 2017	529	ebay.com
4.		Canon G9 X	3.5/5	+ +	..	..	4.5/5	4.5/5	Oct 2015	529	ebay.com
5.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
6.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
7.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
8.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	749	ebay.com
9.		Pentax K-50	5/5	..	..	..	5/5	4.5/5	Jun 2013	599	ebay.com
10.		Pentax K-500	..	..	..	..	4.5/5	4.5/5	Jun 2013	549	ebay.com
11.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
12.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	1,099	ebay.com
13.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	1,099	ebay.com
14.		Sony RX100 III	5/5	+ +	..	82/100	4.5/5	5/5	May 2014	799	ebay.com
15.		Sony RX10	5/5	+	..	80/100	4.5/5	4.5/5	Oct 2013	1,299	ebay.com
16.		Sony RX100 II	5/5	+ +	..	79/100	4.5/5	4.5/5	Jun 2013	749	ebay.com
17.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparisons of ratings among very different cameras or across long time periods 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 your choice using the following search menu. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.

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