Sony A77 II vs A9 III

The Sony Alpha SLT-A77 II and the Sony Alpha A9 III are two digital cameras that were announced, respectively, in May 2014 and November 2023. The A77 II is a DSLR, while the A9 III is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (A77 II) and a full frame (A9 III) 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

Sony A77 II		Sony A9 III
Digital single lens reflex		Mirrorless system camera
Sony A mount lenses		Sony E mount lenses
24 MP – APS-C sensor		24 MP – Full Frame sensor
1080/60p Video		4K/120p Video
ISO 100-25,600 (50 - 51,200)		ISO 250-25,600 (125 - 51,200)
Electronic viewfinder (2359k dots)		Electronic viewfinder (9440k dots)
3.0" LCD – 1229k dots		3.2" LCD – 2100k dots
Fully flexible screen (no touchscreen)		Fully flexible touchscreen
12 shutter flaps per second		120 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
480 shots per battery charge		530 shots per battery charge
143 x 104 x 81 mm, 647 g		136 x 97 x 83 mm, 702 g

Check A77 II offers at
ebay.com
Check A9 III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha SLT-A77 II and the Sony Alpha A9 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 Sony A77 II and the Sony A9 III are illustrated 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 measures are rounded to the nearest millimeter.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A9 III is notably smaller (11 percent) than the Sony A77 II. However, the A9 III is markedly heavier (9 percent) than the A77 II. 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 A77 II gets 480 shots out of its Sony NP-FM500H battery, while the A9 III can take 530 images on a single charge of its Sony NP-FZ100 power pack. The power pack in the A9 III can be charged via the USB port, which can be very convenient when travelling.

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	Street Price
1.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	US$ 1 199	ebay.com
2.		Sony A9 III	136 mm	97 mm	83 mm	702 g	530	Y	Nov 2023	US$ 5 999	amazon.com
3.		Nikon D7100	136 mm	107 mm	76 mm	765 g	950	Y	Feb 2013	US$ 1 199	ebay.com
4.		Nikon D7200	136 mm	107 mm	76 mm	765 g	1110	Y	Mar 2015	US$ 1 199	ebay.com
5.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	US$ 1 299	ebay.com
6.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	US$ 1 099	ebay.com
7.		Sony A1	129 mm	97 mm	81 mm	737 g	530	Y	Jan 2021	US$ 6 499	amazon.com
8.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	US$ 1 999	ebay.com
9.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	US$ 1 999	amazon.com
10.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	US$ 4 499	ebay.com
11.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	US$ 4 499	amazon.com
12.		Sony A58	129 mm	95 mm	78 mm	492 g	690	n	Feb 2013	US$ 599	ebay.com
13.		Sony A68	143 mm	104 mm	81 mm	610 g	540	n	Nov 2015	US$ 699	ebay.com
14.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	US$ 1 399	ebay.com
15.		Sony A6500	120 mm	67 mm	53 mm	453 g	350	Y	Oct 2016	US$ 1 399	ebay.com
16.		Sony A6600	120 mm	67 mm	69 mm	503 g	810	Y	Aug 2019	US$ 1 399	amazon.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
Convert to Imperial

The price is, of course, an important factor in any camera decision. 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 A77 II was launched at a markedly lower price (by 80 percent) than the A9 III, 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 size of the sensor inside a digital camera is one of the key determinants 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. 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 Sony A77 II features an APS-C sensor and the Sony A9 III a full frame sensor. The sensor area in the A9 III is 131 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Technology-wise, the A9 III uses a more advanced image processing engine (Dual BIONZ XR) than the A77 II (BIONZ X), with benefits for noise reduction, color accuracy, and processing speed.

Even though the A9 III has a larger sensor, both cameras offer the same resolution of 24 megapixels. This implies that the A9 III has a lower pixel density and larger individual pixels (with a pixel pitch of 5.94μm versus 3.91μm for the A77 II), which gives it a potential advantage in terms of light gathering capacity. In addition, the A9 III is much more recent (by 9 years and 6 months) than the A77 II, and its sensor will have benefitted from technological advances during this time.

The A9 III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Sony Alpha SLT-A77 II has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 50-51200. The corresponding ISO settings for the Sony Alpha A9 III are ISO 250 to ISO 25600, with the possibility to increase the ISO range to 125-51200.

In terms of underlying technology, the A77 II is build around a CMOS sensor, while the A9 III uses a Stacked CMOS imager. 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 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 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.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
2.		Sony A9 III	Full Frame	24.0	6000	4000	4K/120p	25.4	14.7	3243	96
3.		Nikon D7100	APS-C	24.0	6000	4000	1080/60p	24.2	13.7	1256	83
4.		Nikon D7200	APS-C	24.0	6000	4000	1080/60p	24.5	14.6	1333	87
5.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
6.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
7.		Sony A1	Full Frame	49.8	8640	5760	8k/30p	25.9	14.5	3163	98
8.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
9.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
10.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
11.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
12.		Sony A58	APS-C	19.8	5456	3632	1080/60i	23.3	12.5	753	74
13.		Sony A68	APS-C	24.0	6000	4000	1080/60i	24.1	13.5	701	79
14.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
15.		Sony A6500	APS-C	24.0	6000	4000	4K/30p	24.5	13.7	1405	85
16.		Sony A6600	APS-C	24.0	6000	4000	4K/30p	23.8	13.4	1497	82
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 two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A9 III provides a better video resolution than the A77 II. It can shoot movie footage at 4K/120p, while the A77 II is limited to 1080/60p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The two cameras under review are similar with respect to both having an electronic viewfinder. However, the one in the A9 III offers a substantially higher resolution than the one in the A77 II (9440k vs 2359k dots). The following table reports on some other key feature differences and similarities of the Sony A77 II, the Sony A9 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.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	Y	Y
2.		Sony A9 III	9440	n	3.2 / 2100	full-flex	Y	1/80000s	120.0/s	n	Y
3.		Nikon D7100	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
4.		Nikon D7200	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
5.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
6.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
7.		Sony A1	9437	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
8.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
9.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
10.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
11.		Sony A9 II	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
12.		Sony A58	1440	n	2.7 / 460	tilting	n	1/4000s	5.0/s	Y	Y
13.		Sony A68	1440	Y	2.7 / 460	tilting	n	1/4000s	8.0/s	Y	Y
14.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
15.		Sony A6500	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	Y	Y
16.		Sony A6600	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	n	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 A77 II has one, while the A9 III does not. While the built-in flash of the A77 II is not very powerful, it can at times be useful as a fill-in light.

The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the A9 III is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).

The Sony A9 III 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 A77 II writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the A9 III uses CFexpress (type A) or SDXC cards. The A9 III features dual card slots, which can be very useful in case a memory card fails. In contrast, the A77 II only has one slot. The A9 III supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s), while the A77 II can use UHS-I cards (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 Sony Alpha SLT-A77 II and Sony Alpha A9 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.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
2.		Sony A9 III	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
3.		Nikon D7100	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
4.		Nikon D7200	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
5.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
6.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
7.		Sony A1	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
8.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
9.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
10.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
11.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
12.		Sony A58	Y	stereo / mono	Y	-	mini	2.0	-	-	-
13.		Sony A68	Y	stereo / mono	Y	-	micro	2.0	-	-	-
14.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
15.		Sony A6500	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
16.		Sony A6600	Y	stereo / mono	Y	Y	YES	2.0	Y	Y	Y

It is notable that the A9 III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The A77 II lacks such a headphone port.

Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.

The A9 III is a recent model that features in the current product line-up of Sony. In contrast, the A77 II has been discontinued (but can be found pre-owned on ebay). There has not been a direct replacement model for the A77 II from Sony. Further information on the features and operation of the A77 II and A9 III can be found, respectively, in the Sony A77 II Manual (free pdf) or the online Sony A9 III Manual.

Review summary

So what is the bottom line? Is the Sony A77 II better than the Sony A9 III or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Sony Alpha SLT-A77 II:

• Easier setting verification: Features an LCD display on top to control shooting parameters.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More affordable: Was introduced into a lower priced category (80 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in May 2014).

Reasons to prefer the Sony Alpha A9 III:

• Better image quality: Is equipped with a larger and more technologically advanced sensor.
• Richer colors: The sensor size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger sensor captures a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger sensor produces good images even in poorly lit environments.
• Better jpgs: Has a more modern image processing engine (Dual BIONZ XR vs BIONZ X).
• Better video: Provides higher definition movie capture (4K/120p vs 1080/60p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• More detailed viewfinder: Has higher resolution electronic viewfinder (9440k vs 2359k dots).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.9x vs 0.73x).
• 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 (2100k vs 1229k dots).
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• Faster shutter: Has higher mechanical shutter speed (1/80000s vs 1/8000s) to freeze action.
• Faster burst: Shoots at higher frequency (120 vs 12 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (136x97mm vs 143x104mm) and will fit more readily into a bag.
• Longer lasting: Gets more shots (530 versus 480) out of a single battery charge.
• Easier travel charging: Can be conveniently charged via its USB port.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
• More solid recording: Has a full-sized HDMI port for a sturdy connection to an external recorder.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
• More modern: Reflects 9 years and 6 months of technical progress since the A77 II launch.

If the number of relative strengths (bullet points above) is taken as a guide, the A9 III is the clear winner of the contest (27 : 5 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 Sony A77 II and the Sony A9 III place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens Camera listings whether the two cameras rank among the cream of the crop.

In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the A77 II or the A9 III 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 expert reviews 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	Street Price
1.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	US$ 1 199	ebay.com
2.		Sony A9 III	4.5/5	..	..	..	..	..	Nov 2023	US$ 5 999	amazon.com
3.		Nikon D7100	5/5	+ +	..	85/100	4.5/5	4.5/5	Feb 2013	US$ 1 199	ebay.com
4.		Nikon D7200	4/5	+ +	..	84/100	4.5/5	4.5/5	Mar 2015	US$ 1 199	ebay.com
5.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	US$ 1 299	ebay.com
6.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	US$ 1 099	ebay.com
7.		Sony A1	5/5	o	4.5/5	93/100	4.5/5	5/5	Jan 2021	US$ 6 499	amazon.com
8.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	US$ 1 999	ebay.com
9.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	US$ 1 999	amazon.com
10.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	US$ 4 499	ebay.com
11.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	US$ 4 499	amazon.com
12.		Sony A58	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	US$ 599	ebay.com
13.		Sony A68	3/5	..	..	..	4/5	4/5	Nov 2015	US$ 699	ebay.com
14.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	US$ 1 399	ebay.com
15.		Sony A6500	5/5	+ +	3.5/5	85/100	4.5/5	4.5/5	Oct 2016	US$ 1 399	ebay.com
16.		Sony A6600	4/5	+	4/5	83/100	4.5/5	4/5	Aug 2019	US$ 1 399	amazon.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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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? If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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