Pentax K-70 vs Sony A77

The Pentax K-70 and the Sony Alpha SLT-A77 are two digital cameras that were revealed to the public, respectively, in June 2016 and August 2011. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. Both cameras offer a resolution of 24 megapixels.

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

Headline Specifications

Pentax K-70		Sony A77
Digital single lens reflex		Digital single lens reflex
Pentax K mount lenses		Sony A mount lenses
24 MP – APS-C sensor		24 MP – APS-C sensor
1080/60i Video		1080/60p Video
ISO 100-102,400		ISO 100-16,000 (50 - 25,600)
Optical viewfinder		Electronic viewfinder (2359k dots)
3.0" LCD – 921k dots		3.0" LCD – 921k dots
Swivel screen (not touch-sensitive)		Fully flexible screen (no touchscreen)
6 shutter flaps per second		12 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
410 shots per battery charge		470 shots per battery charge
126 x 93 x 74 mm, 688 g		143 x 104 x 81 mm, 732 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-70 and the Sony Alpha SLT-A77? 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

An illustration of the physical size and weight of the Pentax K-70 and the Sony A77 is provided in the side-by-side display below. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth dimensions are rounded to the nearest millimeter.

The K-70 can be obtained in two different colors (black, silver), while the A77 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 A77 is notably larger (27 percent) than the Pentax K-70. Moreover, the A77 is markedly heavier (6 percent) than the K-70. 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-70 gets 410 shots out of its Pentax D-LI109 battery, while the A77 can take 470 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. 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.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
2.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
3.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
4.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
5.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
6.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	1,099	ebay.com
7.		Pentax K-50	130 mm	97 mm	71 mm	650 g	410	Y	Jun 2013	599	ebay.com
8.		Pentax K-500	130 mm	97 mm	71 mm	646 g	710	n	Jun 2013	549	ebay.com
9.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
10.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	749	ebay.com
11.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	ebay.com
12.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999	ebay.com
13.		Sony A68	143 mm	104 mm	81 mm	610 g	540	n	Nov 2015	699	ebay.com
14.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	1,199	ebay.com
15.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
16.		Sony A6500	120 mm	67 mm	53 mm	453 g	350	Y	Oct 2016	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 obviously take relative prices into account. 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 54 percent) than the A77, which puts it into a different 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.

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. A large sensor will generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have 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 tend to be more expensive and 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.

The two cameras under review do not only share the same sensor size, but also offer an identical resolution of 24 megapixels. This similarity in sensor specs implies that both the K-70 and the A77 have the same pixel density, as well as the same pixel size. It should, however, be noted that the K-70 is much more recent (by 4 years and 9 months) than the A77, and its sensor will have benefitted from technological advances during this time. 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 A77, 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 Pentax K-70 has a native sensitivity range from ISO 100 to ISO 102400. The corresponding ISO settings for the Sony Alpha SLT-A77 are ISO 100 to ISO 16000, with the possibility to increase the ISO range to 50-25600.

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.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

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-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
2.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
3.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
4.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
5.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
6.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
7.		Pentax K-50	APS-C	16.1	4928	3264	1080/30p	23.7	13.0	1120	79
8.		Pentax K-500	APS-C	16.1	4928	3264	1080/30p	23.7	13.1	1087	79
9.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
10.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
11.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
12.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
13.		Sony A68	APS-C	24.0	6000	4000	1080/60i	24.1	13.5	701	79
14.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
15.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
16.		Sony A6500	APS-C	24.0	6000	4000	4K/30p	24.5	13.7	1405	85
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 A77 provides a faster frame rate than the K-70. 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. For example, the A77 has an electronic viewfinder (2359k dots), while the K-70 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 A77 has a higher magnification than the one of the K-70 (0.73x 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-70 and Sony A77 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-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
2.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
3.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
4.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
5.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
6.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
7.		Pentax K-50	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
8.		Pentax K-500	optical	n	3.0 / 921	fixed	n	1/6000s	6.0/s	Y	Y
9.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
10.		Pentax K-S1	optical	n	3.0 / 921	fixed	n	1/6000s	5.4/s	Y	Y
11.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
12.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
13.		Sony A68	1440	Y	2.7 / 460	tilting	n	1/4000s	8.0/s	Y	Y
14.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	Y	Y
15.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
16.		Sony A6500	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/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 A77, 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 Pentax K-70 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-70 writes its imaging data to SDXC cards, while the A77 uses SDXC or Memory Stick PRO Duo cards. 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-70 and Sony Alpha SLT-A77 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-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
2.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
3.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
4.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
5.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
6.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
7.		Pentax K-50	Y	mono / mono	-	-	micro	2.0	-	-	-
8.		Pentax K-500	Y	mono / mono	-	-	-	2.0	-	-	-
9.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
10.		Pentax K-S1	Y	stereo / mono	-	-	micro	2.0	-	-	-
11.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
12.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
13.		Sony A68	Y	stereo / mono	Y	-	micro	2.0	-	-	-
14.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
15.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
16.		Sony A6500	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-

It is notable that the K-70 offers wifi support, while the A77 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Studio photographers will appreciate that the Sony A77 (unlike the K-70) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Travel and landscape photographers will find it useful that the A77 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

Both the K-70 and the A77 have been discontinued, but can regularly be found used on ebay. The A77 was replaced by the Sony A77 II, while the K-70 does not have a direct successor. Further information on the features and operation of the K-70 and A77 can be found, respectively, in the Pentax K-70 Manual (free pdf) or the online Sony A77 Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Pentax K-70 or the Sony A77 – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Advantages of 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.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (126x93mm vs 143x104mm) and thus needs less room in the bag.
• 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 (54 percent cheaper at launch).
• More modern: Reflects 4 years and 9 months of technical progress since the A77 launch.

Arguments in favor of the Sony Alpha SLT-A77:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
• More framing info: Has an electronic viewfinder that displays shooting data.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.73x vs 0.63x).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/6000s) to freeze action.
• Faster burst: Shoots at higher frequency (12 vs 6 flaps/sec) to capture the decisive moment.
• Longer lasting: Gets more shots (470 versus 410) out of a single battery charge.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More heavily discounted: Has been around for much longer (launched in August 2011).

If the count of individual advantages (bullet points above) is taken as a guide, the A77 emerges as the winner of the match-up (11 : 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 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-70 and the Sony A77 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 K-70 or the A77. 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 where reviews by experts come in. 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 (USD)	Street Price
1.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
2.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
3.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
4.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
5.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
6.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	1,099	ebay.com
7.		Pentax K-50	5/5	..	..	..	5/5	4.5/5	Jun 2013	599	ebay.com
8.		Pentax K-500	..	..	..	..	4.5/5	4.5/5	Jun 2013	549	ebay.com
9.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
10.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	749	ebay.com
11.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
12.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	1,999	ebay.com
13.		Sony A68	3/5	..	..	..	4/5	4/5	Nov 2015	699	ebay.com
14.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	1,199	ebay.com
15.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
16.		Sony A6500	5/5	+ +	3.5/5	85/100	4.5/5	4.5/5	Oct 2016	1,399	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. 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. 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 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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