Sony A6400 vs RX100 III

The Sony Alpha A6400 and the Sony Cyber-shot DSC-RX100 III are two digital cameras that were officially introduced, respectively, in January 2019 and May 2014. The A6400 is a mirrorless interchangeable lens camera, while the RX100 III is a fixed lens compact. The cameras are based on an APS-C (A6400) and an one-inch (RX100 III) sensor. The A6400 has a resolution of 24 megapixels, whereas the RX100 III provides 20 MP.

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

Headline Specifications

Sony A6400		Sony RX100 III
Mirrorless system camera		Fixed lens compact camera
Sony E mount lenses		24-70mm f/1.8-2.8
24 MP – APS-C sensor		20 MP – 1" sensor
4K/30p Video		1080/60p Video
ISO 100-32,000 (100 - 102,400)		ISO 100-12,800 (80 - 25,600)
Electronic viewfinder (2359k dots)		Electronic viewfinder (1440k dots)
3.0" LCD – 922k dots		3.0" LCD – 1229k dots
Tilting touchscreen		Tilting screen (no touchscreen)
11 shutter flaps per second		10 shutter flaps per second
Weathersealed body		not weather sealed
410 shots per battery charge		320 shots per battery charge
120 x 67 x 50 mm, 403 g		102 x 58 x 41 mm, 290 g

Check A6400 price at
amazon.com
Check RX100 III offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A6400 and the Sony Cyber-shot DSC-RX100 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

An illustration of the physical size and weight of the Sony A6400 and the Sony RX100 III 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.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony RX100 III is notably smaller (26 percent) than the Sony A6400. It is worth mentioning in this context that the A6400 is splash and dust resistant, while the RX100 III does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the RX100 III has a lens built in, whereas the A6400 is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup. You can compare the optics available for the A6400 and their specifications in the Sony E-Mount Lens Catalog.

Concerning battery life, the A6400 gets 410 shots out of its NP-FW50 battery, while the RX100 III can take 320 images on a single charge of its NP-BX1 power pack. 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. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons 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.		Sony A6400	120 mm	67 mm	50 mm	403 g	410	Y	Jan 2019	899	amazon.com
2.		Sony RX100 III	102 mm	58 mm	41 mm	290 g	320	n	May 2014	799	ebay.com
3.		Canon G7 X	103 mm	60 mm	40 mm	304 g	210	n	Sep 2014	699	ebay.com
4.		Fujifilm X-T30	118 mm	83 mm	47 mm	383 g	380	n	Feb 2019	899	ebay.com
5.		Nikon D5300	125 mm	98 mm	76 mm	480 g	600	n	Oct 2013	799	ebay.com
6.		Sony RX100 VII	102 mm	58 mm	43 mm	302 g	260	n	Jul 2019	1,199	amazon.com
7.		Sony A6100	120 mm	67 mm	59 mm	396 g	420	n	Aug 2019	749	ebay.com
8.		Sony A6300	120 mm	67 mm	49 mm	404 g	400	Y	Feb 2016	999	ebay.com
9.		Sony RX100 IV	102 mm	58 mm	41 mm	298 g	280	n	Jun 2015	999	ebay.com
10.		Sony A5100	110 mm	63 mm	36 mm	283 g	400	n	Aug 2014	549	ebay.com
11.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	599	ebay.com
12.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	329	ebay.com
13.		Sony RX100 II	102 mm	58 mm	38 mm	281 g	350	n	Jun 2013	749	ebay.com
14.		Sony NEX-5R	111 mm	59 mm	39 mm	276 g	330	n	Aug 2012	749	ebay.com
15.		Sony NEX-6	120 mm	67 mm	43 mm	345 g	360	n	Sep 2012	999	ebay.com
16.		Sony RX100	102 mm	58 mm	36 mm	240 g	330	n	Jun 2012	649	ebay.com
17.		Sony NEX-7	120 mm	67 mm	43 mm	400 g	430	n	Aug 2011	1,349	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 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 RX100 III was launched at a lower price than the A6400, 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. 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 tend to be associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Sony A6400 features an APS-C sensor and the Sony RX100 III an one-inch sensor. The sensor area in the RX100 III is 68 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.

With 24MP, the A6400 offers a higher resolution than the RX100 III (20MP), but the A6400 nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 2.41μm for the RX100 III) due to its larger sensor. Moreover, the A6400 is a much more recent model (by 4 years and 8 months) than the RX100 III, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels.

The resolution advantage of the Sony A6400 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A6400 for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the Sony RX100 III are 27.4 x 18.2 inches or 69.5 x 46.3 cm for good quality, 21.9 x 14.6 inches or 55.6 x 37.1 cm for very good quality, and 18.2 x 12.2 inches or 46.3 x 30.9 cm for excellent quality prints.

The A6400 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Sony Alpha A6400 has a native sensitivity range from ISO 100 to ISO 32000, which can be extended to ISO 100-102400. The corresponding ISO settings for the Sony Cyber-shot DSC-RX100 III are ISO 100 to ISO 12800, with the possibility to increase the ISO range to 80-25600.

In terms of underlying technology, the A6400 is build around a CMOS sensor, while the RX100 III uses a BSI-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 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 A6400 provides substantially higher image quality than the RX100 III, with an overall score that is 16 points higher. This advantage is based on 1.6 bits higher color depth, 1.3 EV in additional dynamic range, and 1.5 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 A6400	APS-C	24.0	6000	4000	4K/30p	24.0	13.6	1431	83
2.		Sony RX100 III	1-inch	20.0	5472	3648	1080/60p	22.4	12.3	495	67
3.		Canon G7 X	1-inch	20.0	5472	3648	1080/60p	23.0	12.7	556	71
4.		Fujifilm X-T30	APS-C	26.0	6240	4160	4K/30p	24.1	13.5	1895	83
5.		Nikon D5300	APS-C	24.0	6000	4000	1080/60p	24.0	13.9	1338	83
6.		Sony RX100 VII	1-inch	20.0	5472	3648	4K/30p	21.8	12.4	418	63
7.		Sony A6100	APS-C	24.0	6000	4000	4K/30p	24.1	13.6	1947	84
8.		Sony A6300	APS-C	24.0	6000	4000	4K/30p	24.4	13.7	1437	85
9.		Sony RX100 IV	1-inch	20.0	5472	3648	4K/30p	22.8	12.6	591	70
10.		Sony A5100	APS-C	24.0	6000	4000	1080/60p	23.8	12.7	1347	80
11.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
12.		Sony A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
13.		Sony RX100 II	1-inch	20.0	5472	3648	1080/60p	22.5	12.4	483	67
14.		Sony NEX-5R	APS-C	16.0	4912	3264	1080/60i	23.7	13.1	910	78
15.		Sony NEX-6	APS-C	16.0	4912	3264	1080/60i	23.7	13.1	1018	78
16.		Sony RX100	1-inch	20.0	5472	3648	1080/60p	22.6	12.4	390	66
17.		Sony NEX-7	APS-C	24.0	6000	4000	1080/60i	24.1	13.4	1016	81
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 A6400 provides a higher video resolution than the RX100 III. It can shoot video footage at 4K/30p, while the RX100 III is limited to 1080/60p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The two cameras under consideration are similar with respect to both having an electronic viewfinder. However, the one in the A6400 offers a substantially higher resolution than the one in the RX100 III (2359k vs 1440k dots). The adjacent table lists some of the other core features of the Sony A6400 and Sony RX100 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 A6400	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	Y	n
2.		Sony RX100 III	1440	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
3.		Canon G7 X	none	n	3.0 / 1040	tilting	Y	1/2000s	6.5/s	Y	Y
4.		Fujifilm X-T30	2360	n	3.0 / 1040	tilting	Y	1/4000s	8.0/s	Y	n
5.		Nikon D5300	optical	n	3.2 / 1037	swivel	n	1/4000s	5.0/s	Y	n
6.		Sony RX100 VII	2359	n	3.0 / 921	tilting	Y	1/2000s	90.0/s	Y	Y
7.		Sony A6100	1440	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	Y	n
8.		Sony A6300	2359	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
9.		Sony RX100 IV	2359	n	3.0 / 1228	tilting	n	1/2000s	16.0/s	Y	Y
10.		Sony A5100	none	n	3.0 / 922	tilting	Y	1/4000s	6.0/s	Y	n
11.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
12.		Sony A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
13.		Sony RX100 II	optional	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
14.		Sony NEX-5R	optional	n	3.0 / 920	tilting	Y	1/4000s	10.0/s	n	n
15.		Sony NEX-6	2359	n	3.0 / 921	tilting	n	1/4000s	10.0/s	Y	n
16.		Sony RX100	none	n	3.0 / 1229	fixed	n	1/2000s	10.0/s	Y	Y
17.		Sony NEX-7	2359	n	3.0 / 921	tilting	n	1/4000s	10.0/s	Y	n
Notes: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The A6400 has a touchscreen, while the RX100 III has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

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 A6400 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).

Concerning the storage of imaging data, both the A6400 and the RX100 III write their files to 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 Sony Alpha A6400 and Sony Cyber-shot DSC-RX100 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 A6400	Y	stereo / mono	Y	-	micro	2.0	Y	Y	Y
2.		Sony RX100 III	-	stereo / mono	-	-	micro	2.0	Y	Y	-
3.		Canon G7 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
4.		Fujifilm X-T30	Y	stereo / mono	Y	-	micro	3.1	Y	-	Y
5.		Nikon D5300	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
6.		Sony RX100 VII	-	stereo / mono	Y	-	micro	2.0	Y	Y	Y
7.		Sony A6100	Y	stereo / mono	Y	-	micro	2.0	Y	Y	Y
8.		Sony A6300	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
9.		Sony RX100 IV	-	stereo / mono	-	-	micro	2.0	Y	Y	-
10.		Sony A5100	-	stereo / mono	-	-	micro	2.0	Y	Y	-
11.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
12.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
13.		Sony RX100 II	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
14.		Sony NEX-5R	Y	stereo / mono	-	-	mini	2.0	Y	-	-
15.		Sony NEX-6	Y	stereo / mono	-	-	mini	2.0	Y	-	-
16.		Sony RX100	-	stereo / mono	-	-	micro	2.0	-	-	-
17.		Sony NEX-7	Y	stereo / mono	Y	-	mini	2.0	-	-	-

It is notable that the A6400 has a hotshoe, while the RX100 III does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.

The A6400 is a recent model that features in the current product line-up of Sony. In contrast, the RX100 III has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the RX100 III was succeeded by the Sony RX100 IV. Further information on the features and operation of the A6400 and RX100 III can be found, respectively, in the Sony A6400 Manual (free pdf) or the online Sony RX100 III Manual.

Review summary

So what conclusions can be drawn? Is the Sony A6400 better than the Sony RX100 III or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Sony Alpha A6400:

• More detail: Offers more megapixels (24 vs 20MP) with a 10% higher linear resolution.
• Better image quality: Scores substantially higher (16 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (1.6 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (1.3 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (1.5 stops ISO advantage).
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Better sound: Can connect to an external microphone for higher quality sound recording.
• More detailed viewfinder: Has higher resolution electronic viewfinder (2359k vs 1440k dots).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.70x vs 0.59x).
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• Faster shutter: Has higher mechanical shutter speed (1/4000s vs 1/2000s) to freeze action.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• More flexible: Accepts interchangeable lenses, so that lens characteristics can be altered.
• Longer lasting: Can take more shots (410 versus 320) 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.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• More modern: Reflects 4 years and 8 months of technical progress since the RX100 III launch.

Arguments in favor of the Sony Cyber-shot DSC-RX100 III:

• More detailed LCD: Has a higher resolution rear screen (1229k vs 922k dots).
• Ready to shoot: Has an integrated lens, whereas the A6400 necessitates an extra lens.
• More compact: Is smaller (102x58mm vs 120x67mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight even though it has a lens built in (unlike the A6400).
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More heavily discounted: Has been around for much longer (launched in May 2014).

If the count of individual advantages (bullet points above) is taken as a guide, the A6400 is the clear winner of the match-up (19 : 7 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 wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro 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 A6400 and the Sony RX100 III place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best Travel-Zoom 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 says little about, for example, the shooting experience and imaging performance of the A6400 and the RX100 III in practical situations. 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 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 (USD)	Street Price
1.		Sony A6400	4/5	+	4/5	85/100	4.5/5	4/5	Jan 2019	899	amazon.com
2.		Sony RX100 III	5/5	+ +	..	82/100	4.5/5	5/5	May 2014	799	ebay.com
3.		Canon G7 X	4/5	+ +	..	77/100	4.5/5	4.5/5	Sep 2014	699	ebay.com
4.		Fujifilm X-T30	5/5	+ +	5/5	84/100	4.5/5	4.5/5	Feb 2019	899	ebay.com
5.		Nikon D5300	4/5	+ +	..	79/100	4.5/5	4.5/5	Oct 2013	799	ebay.com
6.		Sony RX100 VII	4.5/5	..	4/5	..	4/5	5/5	Jul 2019	1,199	amazon.com
7.		Sony A6100	..	..	4/5	82/100	4/5	5/5	Aug 2019	749	ebay.com
8.		Sony A6300	4.5/5	+	..	85/100	5/5	5/5	Feb 2016	999	ebay.com
9.		Sony RX100 IV	4.5/5	+ +	..	85/100	4/5	4.5/5	Jun 2015	999	ebay.com
10.		Sony A5100	4.5/5	+	..	..	4.5/5	5/5	Aug 2014	549	ebay.com
11.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	599	ebay.com
12.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	329	ebay.com
13.		Sony RX100 II	5/5	+ +	..	79/100	4.5/5	4.5/5	Jun 2013	749	ebay.com
14.		Sony NEX-5R	..	..	..	..	4.5/5	4.5/5	Aug 2012	749	ebay.com
15.		Sony NEX-6	5/5	+ +	..	78/100	4.5/5	4.5/5	Sep 2012	999	ebay.com
16.		Sony RX100	5/5	+ +	..	78/100	4/5	5/5	Jun 2012	649	ebay.com
17.		Sony NEX-7	5/5	+ +	..	81/100	4.5/5	5/5	Aug 2011	1,349	ebay.com
Notes: (+ +) 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. 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. 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

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