Pentax K-50 vs Sony A58

The Pentax K-50 and the Sony Alpha SLT-A58 are two digital cameras that were revealed to the public, respectively, in June 2013 and February 2013. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Pentax has a resolution of 16.1 megapixels, whereas the Sony provides 19.8 MP.

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

Headline Specifications

Pentax K-50		Sony A58
Digital single lens reflex		Digital single lens reflex
Pentax K mount lenses		Sony A mount lenses
16.1 MP – APS-C sensor		19.8 MP – APS-C sensor
1080/30p Video		1080/60i Video
ISO 100-51,200		ISO 100-16,000 (100 - 25,600)
Optical viewfinder		Electronic viewfinder (1440k dots)
3.0" LCD – 921k dots		2.7" LCD – 460k dots
Fixed screen (not touch-sensitive)		Tilting screen (no touchscreen)
6 shutter flaps per second		5 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		not weather sealed
410 shots per battery charge		690 shots per battery charge
130 x 97 x 71 mm, 650 g		129 x 95 x 78 mm, 492 g

Check K-50 offers at
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Check A58 offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-50 and the Sony Alpha SLT-A58? 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-50 and the Sony A58 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 size dimensions are rounded to the nearest millimeter.

The K-50 can be obtained in three different colors (black, red, white), while the A58 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 A58 is somewhat smaller (3 percent) than the Pentax K-50. Moreover, the A58 is markedly lighter (24 percent) than the K-50. It is worth mentioning in this context that the K-50 is splash and dust resistant, while the A58 does not feature any corresponding weather-sealing.

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-50 gets 410 shots out of its Pentax D-LI109 battery, while the A58 can take 690 images on a single charge of its Sony NP-FM500H power pack.

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	Street Price
1.		Pentax K-50	130 mm	97 mm	71 mm	650 g	410	Y	Jun 2013	US$ 599	ebay.com
2.		Sony A58	129 mm	95 mm	78 mm	492 g	690	n	Feb 2013	US$ 599	ebay.com
3.		Nikon D3300	124 mm	98 mm	76 mm	430 g	700	n	Jan 2014	US$ 499	ebay.com
4.		Nikon Df	144 mm	110 mm	67 mm	760 g	1400	Y	Nov 2013	US$ 2 749	ebay.com
5.		Olympus E-M10	119 mm	82 mm	46 mm	396 g	320	n	Jan 2014	US$ 699	ebay.com
6.		Panasonic GH4	133 mm	93 mm	84 mm	560 g	500	Y	Feb 2014	US$ 1 499	ebay.com
7.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	US$ 1 299	ebay.com
8.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	US$ 1 099	ebay.com
9.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	US$ 1 099	ebay.com
10.		Pentax K-30	130 mm	97 mm	71 mm	650 g	410	Y	May 2012	US$ 849	ebay.com
11.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	US$ 649	ebay.com
12.		Pentax K-500	130 mm	97 mm	71 mm	646 g	710	n	Jun 2013	US$ 549	ebay.com
13.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	US$ 749	ebay.com
14.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	US$ 1 999	ebay.com
15.		Sony A68	143 mm	104 mm	81 mm	610 g	540	n	Nov 2015	US$ 699	ebay.com
16.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	US$ 599	ebay.com
17.		Sony RX100	102 mm	58 mm	36 mm	240 g	330	n	Jun 2012	US$ 649	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 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 two cameras under review were launched at the same price and fall into the same 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 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. 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Both cameras under consideration feature an APS-C sensor and have a format factor (sometimes also referred to as "crop factor") of 1.5. Within the spectrum of camera sensors, this places the review cameras among the medium-sized sensor cameras that aim to strike a balance between image quality and portability. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

While the two cameras under review share the same sensor size, the A58 offers a higher resolution of 19.8 megapixels, compared with 16.1 MP of the K-50. This megapixels advantage translates into a 11 percent gain in linear resolution. On the other hand, these sensor specs imply that the A58 has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 4.31μm versus 4.77μm for the K-50). Moreover, it should be noted, that the K-50 is a somewhat more recent model (by 3 months) than the A58, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of individual pixels.

The resolution advantage of the Sony A58 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A58 for good quality output (200 dots per inch) amounts to 27.3 x 18.2 inches or 69.3 x 46.1 cm, for very good quality (250 dpi) 21.8 x 14.5 inches or 55.4 x 36.9 cm, and for excellent quality (300 dpi) 18.2 x 12.1 inches or 46.2 x 30.8 cm. The corresponding values for the Pentax K-50 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-50 has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Sony Alpha SLT-A58 are ISO 100 to ISO 16000, 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.

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"). Of the two cameras under review, the K-50 has a notably higher overall DXO score than the A58 (overall score 5 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.4 bits higher color depth, 0.5 EV in additional dynamic range, and 0.6 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-50	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1120	79
2.		Sony A58	APS-C	19.8	5456	3632	1080/60i	23.3	12.5	753	74
3.		Nikon D3300	APS-C	24.0	6000	4000	1080/60p	24.3	12.8	1385	82
4.		Nikon Df	Full Frame	16.2	4928	3280	none	24.6	13.1	3279	89
5.		Olympus E-M10	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.3	884	72
6.		Panasonic GH4	Four Thirds	15.9	4608	3456	4K/30p	23.2	12.8	791	74
7.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
8.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
9.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
10.		Pentax K-30	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1129	79
11.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
12.		Pentax K-500	APS-C	16.1	4928	3264	1080/30p	23.7	13.1	1087	79
13.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
14.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
15.		Sony A68	APS-C	24.0	6000	4000	1080/60i	24.1	13.5	701	79
16.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
17.		Sony RX100	1-inch	20.0	5472	3648	1080/60p	22.6	12.4	390	66
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 have a sensor with sufficiently fast read-out times for moving pictures, but the A58 provides a faster frame rate than the K-50. It can shoot movie footage at 1080/60i, while the Pentax is limited to 1080/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A58 has an electronic viewfinder (1440k dots), while the K-50 has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the K-50 has a higher magnification than the one of the A58 (0.61x vs 0.57x), 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 Pentax K-50 and Sony A58 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.		Pentax K-50	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
2.		Sony A58	1440	n	2.7 / 460	tilting	n	1/4000s	5.0/s	Y	Y
3.		Nikon D3300	optical	n	3.0 / 921	fixed	n	1/4000s	5.0/s	Y	n
4.		Nikon Df	optical	Y	3.2 / 921	fixed	n	1/4000s	5.5/s	n	n
5.		Olympus E-M10	1440	n	3.0 / 1037	tilting	Y	1/4000s	8.0/s	Y	Y
6.		Panasonic GH4	2359	n	3.0 / 1036	swivel	Y	1/8000s	12.0/s	Y	n
7.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
8.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
9.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
10.		Pentax K-30	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
11.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
12.		Pentax K-500	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
13.		Pentax K-S1	optical	n	3.0 / 921	fixed	n	1/6000s	5.4/s	Y	Y
14.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
15.		Sony A68	1440	Y	2.7 / 460	tilting	n	1/4000s	8.0/s	Y	Y
16.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
17.		Sony RX100	none	n	3.0 / 1229	fixed	n	1/2000s	10.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

The Pentax K-50 has 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-50 writes its imaging data to SDXC cards, while the A58 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-50 and Sony Alpha SLT-A58 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-50	Y	mono / mono	-	-	micro	2.0	-	-	-
2.		Sony A58	Y	stereo / mono	Y	-	mini	2.0	-	-	-
3.		Nikon D3300	Y	mono / mono	Y	-	mini	2.0	-	-	-
4.		Nikon Df	Y	- / -	-	-	mini	2.0	-	-	-
5.		Olympus E-M10	Y	stereo / mono	-	-	micro	2.0	Y	-	-
6.		Panasonic GH4	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
7.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
8.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
9.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
10.		Pentax K-30	Y	mono / mono	-	-	-	2.0	-	-	-
11.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
12.		Pentax K-500	Y	mono / mono	-	-	-	2.0	-	-	-
13.		Pentax K-S1	Y	stereo / mono	-	-	micro	2.0	-	-	-
14.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A68	Y	stereo / mono	Y	-	micro	2.0	-	-	-
16.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
17.		Sony RX100	-	stereo / mono	-	-	micro	2.0	-	-	-

It is notable that the A58 has a microphone port, which can help to improve the quality of audio recordings by attaching an external microphone. The K-50 does not feature such a mic input.

Both the K-50 and the A58 have been discontinued, but can regularly be found used on ebay. The A58 was replaced by the Sony A68, while the K-50 was followed by the Pentax K-70. Further information on the features and operation of the K-50 and A58 can be found, respectively, in the Pentax K-50 Manual (free pdf) or the online Sony A58 Manual.

Review summary

So how do things add up? Is the Pentax K-50 better than the Sony A58 or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer the Pentax K-50:

• Better image quality: Scores markedly higher (5 points) in the DXO overall assessment.
• Better low-light sensitivity: Requires less light for good images (0.6 stops ISO advantage).
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.61x vs 0.57x).
• Larger screen: Has a bigger rear LCD (3.0" vs 2.7") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 460k dots).
• Faster shutter: Has higher mechanical shutter speed (1/6000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (6 vs 5 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• More modern: Is somewhat more recent (announced 3 months after the A58).

Advantages of the Sony Alpha SLT-A58:

• More detail: Has more megapixels (19.8 vs 16.1MP), which boosts linear resolution by 11%.
• Better video: Provides higher movie framerates (1080/60i versus 1080/30p).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• More framing info: Has an electronic viewfinder that displays shooting data.
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Less heavy: Has a lower weight (by 158g or 24 percent) and is thus easier to take along.
• Longer lasting: Gets more shots (690 versus 410) out of a single battery charge.
• More heavily discounted: Has been on the market for longer (launched in February 2013).

If the count of individual advantages (bullet points above) is taken as a guide, the K-50 emerges as the winner of the contest (11 : 8 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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-50 and the Sony A58 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 incomplete and does no justice, for example, to the way the K-50 or the A58 perform in practice. 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	Street Price
1.		Pentax K-50	5/5	..	..	..	5/5	4.5/5	Jun 2013	US$ 599	ebay.com
2.		Sony A58	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	US$ 599	ebay.com
3.		Nikon D3300	3/5	+	..	77/100	4.5/5	4.5/5	Jan 2014	US$ 499	ebay.com
4.		Nikon Df	4/5	..	..	81/100	4/5	4/5	Nov 2013	US$ 2 749	ebay.com
5.		Olympus E-M10	4/5	..	..	80/100	5/5	5/5	Jan 2014	US$ 699	ebay.com
6.		Panasonic GH4	5/5	+ +	..	85/100	5/5	5/5	Feb 2014	US$ 1 499	ebay.com
7.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	US$ 1 299	ebay.com
8.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	US$ 1 099	ebay.com
9.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	US$ 1 099	ebay.com
10.		Pentax K-30	4/5	..	..	78/100	4.5/5	4.5/5	May 2012	US$ 849	ebay.com
11.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	US$ 649	ebay.com
12.		Pentax K-500	..	..	..	..	4.5/5	4.5/5	Jun 2013	US$ 549	ebay.com
13.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	US$ 749	ebay.com
14.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	US$ 1 999	ebay.com
15.		Sony A68	3/5	..	..	..	4/5	4/5	Nov 2015	US$ 699	ebay.com
16.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	US$ 599	ebay.com
17.		Sony RX100	5/5	+ +	..	78/100	4/5	5/5	Jun 2012	US$ 649	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

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Other camera comparisons

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