Sony A7R IIIA vs A7S III

The Sony Alpha A7R IIIA and the Sony Alpha 7S III are two digital cameras that were revealed to the public, respectively, in April 2021 and July 2020. Both the A7R IIIA and the A7S III are mirrorless interchangeable lens cameras that are equipped with a full frame sensor. The A7R IIIA has a resolution of 42.2 megapixels, whereas the A7S III provides 12 MP.

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

Headline Specifications

Sony A7R IIIA		Sony A7S III
Mirrorless system camera		Mirrorless system camera
Sony E mount lenses		Sony E mount lenses
42.2 MP – Full Frame sensor		12 MP – Full Frame sensor
4K/30p Video		4K/120p Video
ISO 100-32,000 (50 - 102,400)		ISO 80-102,400 (40 - 409,600)
Electronic viewfinder (3686k dots)		Electronic viewfinder (9440k dots)
3.0" LCD – 2340k dots		3.0" LCD – 1440k dots
Tilting touchscreen		Swivel touchscreen
10 shutter flaps per second		10 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
650 shots per battery charge		600 shots per battery charge
127 x 96 x 74 mm, 650 g		127 x 97 x 81 mm, 699 g

Check A7R IIIA price at
amazon.com
Check A7S III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A7R IIIA and the Sony Alpha 7S 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 side-by-side display below illustrates the physical size and weight of the Sony A7R IIIA and the Sony A7S III. 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 dimensions 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 A7S III is somewhat larger (1 percent) than the Sony A7R IIIA. Moreover, the A7S III is markedly heavier (8 percent) than the A7R IIIA. 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. In this particular case, both cameras feature the same lens mount, so that they can use the same lenses. You can compare the optics available in the Sony FE Lens Catalog. Mirrorless cameras, such as the two under consideration, have the additional advantage of having a short flange to focal plane distance, which makes it possible to mount many lenses from other systems onto the camera via adapters.

The battery packs of both cameras can be charged via USB, which can be very convenient when travelling.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.		Sony A7R IIIA	127 mm	96 mm	74 mm	650 g	650	Y	Apr 2021	US$ 3 199	amazon.com
2.		Sony A7S III	127 mm	97 mm	81 mm	699 g	600	Y	Jul 2020	US$ 3 499	amazon.com
3.		Sony A1	129 mm	97 mm	81 mm	737 g	530	Y	Jan 2021	US$ 6 499	amazon.com
4.		Sony A7R II	127 mm	96 mm	60 mm	625 g	290	Y	Jun 2015	US$ 3 199	ebay.com
5.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	US$ 3 199	ebay.com
6.		Sony A7R IV	129 mm	96 mm	78 mm	665 g	670	Y	Jul 2019	US$ 3 499	ebay.com
7.		Sony A7R IVA	129 mm	96 mm	78 mm	665 g	670	Y	Apr 2021	US$ 3 499	amazon.com
8.		Sony A7R V	131 mm	97 mm	82 mm	723 g	530	Y	Oct 2022	US$ 3 899	amazon.com
9.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	US$ 2 999	ebay.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 A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	US$ 3 199	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The A7R IIIA was somewhat cheaper (by 9 percent) than the A7S III at launch, but both cameras fall into the same price category. 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.

Both cameras under consideration feature a full frame sensor, but their sensors differ slightly in size. The sensor area in the A7S III is 2 percent smaller. They nevertheless have the same format factor of 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Technology-wise, the A7S III uses a more advanced image processing engine (BIONZ XR) than the A7R IIIA (BIONZ X), with benefits for noise reduction, color accuracy, and processing speed.

With 42.2MP, the A7R IIIA offers a higher resolution than the A7S III (12MP), but the A7R IIIA has smaller individual pixels (pixel pitch of 4.52μm versus 8.40μm for the A7S III). However, the A7R IIIA is a somewhat more recent model (by 8 months) than the A7S III, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels. Coming back to sensor resolution, it should be mentioned that the A7R IIIA has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Sony A7R IIIA implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7R IIIA for good quality output (200 dots per inch) amounts to 39.8 x 26.5 inches or 101 x 67.4 cm, for very good quality (250 dpi) 31.8 x 21.2 inches or 80.8 x 53.9 cm, and for excellent quality (300 dpi) 26.5 x 17.7 inches or 67.3 x 44.9 cm. The corresponding values for the Sony A7S III are 21.2 x 14.2 inches or 53.8 x 36 cm for good quality, 17 x 11.3 inches or 43.1 x 28.8 cm for very good quality, and 14.1 x 9.4 inches or 35.9 x 24 cm for excellent quality prints.

Unlike the A7S III, the A7R IIIA 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 Sony Alpha A7R IIIA has a native sensitivity range from ISO 100 to ISO 32000, which can be extended to ISO 50-102400. The corresponding ISO settings for the Sony Alpha 7S III are ISO 80 to ISO 102400, with the possibility to increase the ISO range to 40-409600.

Technology-wise, both cameras are equipped with BSI-CMOS (Backside Illuminated 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 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 A7R IIIA provides substantially higher image quality than the A7S III, with an overall score that is 14 points higher. This advantage is based on 2.3 bits higher color depth, 0.8 EV in additional dynamic range, and 0.5 stops in additional low light sensitivity. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Sony A7R IIIA	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
2.		Sony A7S III	Full Frame	12.0	4240	2832	4K/120p	23.7	13.9	2520	86
3.		Sony A1	Full Frame	49.8	8640	5760	8k/30p	25.9	14.5	3163	98
4.		Sony A7R II	Full Frame	42.2	7952	5304	4K/30p	26.0	13.9	3434	98
5.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
6.		Sony A7R IV	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
7.		Sony A7R IVA	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
8.		Sony A7R V	Full Frame	60.2	9504	6336	8k/24p	26.5	14.8	3187	100
9.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
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 A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92

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 A7S III provides a faster frame rate than the A7R IIIA. It can shoot movie footage at 4K/120p, while the A7R IIIA is limited to 4K/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The two cameras under review are similar with respect to both having an electronic viewfinder. However, the one in the A7S III offers a substantially higher resolution than the one in the A7R IIIA (9440k vs 3686k dots). The adjacent table lists some of the other core features of the Sony A7R IIIA and Sony A7S III 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.		Sony A7R IIIA	3686	n	3.0 / 2340	tilting	Y	1/8000s	10.0/s	n	Y
2.		Sony A7S III	9440	n	3.0 / 1440	swivel	Y	1/8000s	10.0/s	n	Y
3.		Sony A1	9437	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
4.		Sony A7R II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
5.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
6.		Sony A7R IV	5760	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
7.		Sony A7R IVA	5760	n	3.0 / 2340	tilting	Y	1/8000s	10.0/s	n	Y
8.		Sony A7R V	9440	n	3.2 / 2100	full-flex	Y	1/8000s	10.0/s	n	Y
9.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/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 A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

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, both cameras under consideration feature an 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 A7R IIIA 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 A7R IIIA writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the A7S III uses CFexpress (type A) or SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. However, while the A7S III supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s) on both slots, the A7R IIIA supports UHS-II only on its first slot and UHS-I (data transfer speed up to 104 MB/s) on the second one.

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 A7R IIIA and Sony Alpha 7S 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 A7R IIIA	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
2.		Sony A7S III	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
3.		Sony A1	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
4.		Sony A7R II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
5.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
6.		Sony A7R IV	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
7.		Sony A7R IVA	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
8.		Sony A7R V	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
9.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	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 A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y

Studio photographers will appreciate that the Sony A7R IIIA (unlike the A7S III) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the A7R IIIA and the A7S III are recent models that are part of the current product line-up. The A7S III replaced the earlier Sony A7S II, while the A7R IIIA followed on from the Sony A7R II. Further information on the features and operation of the A7R IIIA and A7S III can be found, respectively, in the Sony A7R IIIA Manual (free pdf) or the online Sony A7S III Manual.

Review summary

So what conclusions can be drawn? Is the Sony A7R IIIA better than the Sony A7S 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 A7R IIIA:

• More detail: Offers more megapixels (42.2 vs 12MP) with a 87% higher linear resolution.
• 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 image quality: Scores substantially higher (14 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (2.3 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (0.8 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (0.5 stops ISO advantage).
• More detailed LCD: Has a higher resolution rear screen (2340k vs 1440k dots).
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More modern: Is somewhat more recent (announced 8 months after the A7S III).

Advantages of the Sony Alpha 7S III:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better jpgs: Has a more modern image processing engine (BIONZ XR vs BIONZ X).
• Better video: Provides higher movie framerates (4K/120p versus 4K/30p).
• More detailed viewfinder: Has higher resolution electronic viewfinder (9440k vs 3686k dots).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.91x vs 0.78x).
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• More solid recording: Has a full-sized HDMI port for a sturdy connection to an external recorder.
• More heavily discounted: Has been on the market for longer (launched in July 2020).

If the count of individual advantages (bullet points above) is taken as a guide, the A7R IIIA emerges as the winner of the contest (12 : 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 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 A7R IIIA and the Sony A7S III place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera listing 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 partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the A7R IIIA or the A7S 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 hands-on reviews by experts 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.		Sony A7R IIIA	..	+ +	4/5	90/100	4.5/5	5/5	Apr 2021	US$ 3 199	amazon.com
2.		Sony A7S III	4.5/5	+ +	5/5	91/100	4.5/5	5/5	Jul 2020	US$ 3 499	amazon.com
3.		Sony A1	5/5	o	4.5/5	93/100	4.5/5	5/5	Jan 2021	US$ 6 499	amazon.com
4.		Sony A7R II	5/5	+ +	5/5	90/100	5/5	5/5	Jun 2015	US$ 3 199	ebay.com
5.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	US$ 3 199	ebay.com
6.		Sony A7R IV	5/5	+	4.5/5	91/100	4.5/5	5/5	Jul 2019	US$ 3 499	ebay.com
7.		Sony A7R IVA	5/5	+	4.5/5	91/100	4.5/5	5/5	Apr 2021	US$ 3 499	amazon.com
8.		Sony A7R V	5/5	+ +	4.5/5	92/100	..	..	Oct 2022	US$ 3 899	amazon.com
9.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	US$ 2 999	ebay.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 A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	US$ 3 199	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Check A7R IIIA price at
amazon.com
Check A7S III price at
amazon.com

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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Check A7R IIIA price at
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Check A7S III price at
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