Sony A5100 vs RX10 III

The Sony Alpha A5100 and the Sony Cyber-shot DSC-RX10 III are two digital cameras that were announced, respectively, in August 2014 and March 2016. The A5100 is a mirrorless interchangeable lens camera, while the RX10 III is a fixed lens compact. The cameras are based on an APS-C (A5100) and an one-inch (RX10 III) sensor. The A5100 has a resolution of 24 megapixels, whereas the RX10 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 A5100		Sony RX10 III
Mirrorless system camera		Fixed lens compact camera
Sony E mount lenses		24-600mm f/2.4-4.0
24 MP – APS-C sensor		20 MP – 1" sensor
1080/60p Video		4K/30p Video
ISO 100-25,600		ISO 100-12,800 (64 - 25,600)
No viewfinder, LCD framing		Electronic viewfinder (2359k dots)
3.0" LCD – 922k dots		3.0" LCD – 1229k dots
Tilting touchscreen		Tilting screen (no touchscreen)
6 shutter flaps per second		14 shutter flaps per second
not weather sealed		Weathersealed body
400 shots per battery charge		420 shots per battery charge
110 x 63 x 36 mm, 283 g		133 x 94 x 127 mm, 1051 g

Check A5100 offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A5100 and the Sony Cyber-shot DSC-RX10 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 A5100 and the Sony RX10 III is provided in the side-by-side display below. 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 measures are rounded to the nearest millimeter.

The A5100 can be obtained in two different colors (black, white), while the RX10 III 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 RX10 III is considerably larger (80 percent) than the Sony A5100. It is noteworthy in this context that the RX10 III is splash and dust-proof, while the A5100 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the RX10 III has a lens built in, whereas the A5100 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 A5100 and their specifications in the Sony E-Mount Lens Catalog.

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	Street Price
1.		Sony A5100	110 mm	63 mm	36 mm	283 g	400	n	Aug 2014	US$ 549	ebay.com
2.		Sony RX10 III	133 mm	94 mm	127 mm	1051 g	420	Y	Mar 2016	US$ 1 499	ebay.com
3.		Panasonic FZ2500	138 mm	102 mm	135 mm	915 g	350	n	Sep 2016	US$ 1 199	amazon.com
4.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	US$ 329	ebay.com
5.		Sony A5000	110 mm	63 mm	36 mm	269 g	420	n	Jan 2014	US$ 449	ebay.com
6.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	US$ 599	ebay.com
7.		Sony NEX-3	117 mm	62 mm	33 mm	297 g	330	n	May 2010	US$ 599	ebay.com
8.		Sony NEX-3N	110 mm	62 mm	35 mm	269 g	480	n	Feb 2013	US$ 499	ebay.com
9.		Sony NEX-5T	111 mm	59 mm	39 mm	276 g	330	n	Aug 2013	US$ 699	ebay.com
10.		Sony NEX-F3	117 mm	67 mm	42 mm	314 g	470	n	May 2012	US$ 599	ebay.com
11.		Sony RX10	129 mm	88 mm	102 mm	813 g	420	Y	Oct 2013	US$ 1 299	ebay.com
12.		Sony RX10 II	129 mm	88 mm	102 mm	813 g	400	Y	Jun 2015	US$ 1 299	ebay.com
13.		Sony RX10 IV	133 mm	94 mm	145 mm	1095 g	400	Y	Sep 2017	US$ 1 699	amazon.com
14.		Sony RX100	102 mm	58 mm	36 mm	240 g	330	n	Jun 2012	US$ 649	ebay.com
15.		Sony RX100 II	102 mm	58 mm	38 mm	281 g	350	n	Jun 2013	US$ 749	ebay.com
16.		Sony RX100 IV	102 mm	58 mm	41 mm	298 g	280	n	Jun 2015	US$ 999	ebay.com
17.		Sony RX100 V	102 mm	58 mm	41 mm	299 g	220	n	Oct 2016	US$ 999	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. 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. 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. 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 more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A5100 features an APS-C sensor and the Sony RX10 III an one-inch sensor. The sensor area in the RX10 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 A5100 offers a higher resolution than the RX10 III (20MP), but the A5100 nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 2.41μm for the RX10 III) due to its larger sensor. However, the RX10 III is a somewhat more recent model (by 1 year and 7 months) than the A5100, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels.

The resolution advantage of the Sony A5100 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A5100 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 RX10 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 A5100 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Sony Alpha A5100 has a native sensitivity range from ISO 100 to ISO 25600. The corresponding ISO settings for the Sony Cyber-shot DSC-RX10 III are ISO 100 to ISO 12800, with the possibility to increase the ISO range to 64-25600.

In terms of underlying technology, the A5100 is build around a CMOS sensor, while the RX10 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.

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"). Of the two cameras under review, the A5100 has a notably higher overall DXO score than the RX10 III (overall score 10 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.7 bits higher color depth, 0.1 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 A5100	APS-C	24.0	6000	4000	1080/60p	23.8	12.7	1347	80
2.		Sony RX10 III	1-inch	20.0	5472	3648	4K/30p	23.1	12.6	472	70
3.		Panasonic FZ2500	1-inch	20.0	5472	3648	4K/30p	23.0	12.6	538	70
4.		Sony A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
5.		Sony A5000	APS-C	19.8	5456	3632	1080/60i	23.8	13.0	1089	79
6.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
7.		Sony NEX-3	APS-C	14.0	4592	3056	720/30p	22.1	12.0	830	68
8.		Sony NEX-3N	APS-C	16.0	4912	3264	1080/60i	22.8	12.5	1067	74
9.		Sony NEX-5T	APS-C	16.0	4912	3264	1080/60p	23.6	13.0	1015	78
10.		Sony NEX-F3	APS-C	16.0	4912	3264	1080/60i	22.7	12.3	1114	73
11.		Sony RX10	1-inch	20.0	5472	3648	1080/60p	22.9	12.6	474	69
12.		Sony RX10 II	1-inch	20.0	5472	3648	4K/30p	23.0	12.6	531	70
13.		Sony RX10 IV	1-inch	20.0	5472	3648	4K/30p	22.0	12.2	408	63
14.		Sony RX100	1-inch	20.0	5472	3648	1080/60p	22.6	12.4	390	66
15.		Sony RX100 II	1-inch	20.0	5472	3648	1080/60p	22.5	12.4	483	67
16.		Sony RX100 IV	1-inch	20.0	5472	3648	4K/30p	22.8	12.6	591	70
17.		Sony RX100 V	1-inch	20.0	5472	3648	4K/30p	22.8	12.4	586	70
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. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the RX10 III provides a better video resolution than the A5100. It can shoot movie footage at 4K/30p, while the A5100 is limited to 1080/60p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the RX10 III has an electronic viewfinder (2359k dots), which can be very helpful when shooting in bright sunlight. In contrast, the A5100 relies on live view and the rear LCD for framing. The following table reports on some other key feature differences and similarities of the Sony A5100, the Sony RX10 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 A5100	none	n	3.0 / 922	tilting	Y	1/4000s	6.0/s	Y	n
2.		Sony RX10 III	2359	Y	3.0 / 1229	tilting	n	1/2000s	14.0/s	Y	Y
3.		Panasonic FZ2500	2360	n	3.0 / 1040	swivel	Y	1/4000s	12.0/s	Y	Y
4.		Sony A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
5.		Sony A5000	none	n	3.0 / 461	tilting	n	1/4000s	3.5/s	Y	n
6.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
7.		Sony NEX-3	optional	n	3.0 / 920	tilting	n	1/4000s	7.0/s	n	n
8.		Sony NEX-3N	optional	n	3.0 / 460	tilting	n	1/4000s	4.0/s	Y	n
9.		Sony NEX-5T	optional	n	3.0 / 922	tilting	Y	1/4000s	10.0/s	n	n
10.		Sony NEX-F3	optional	n	3.0 / 920	tilting	n	1/4000s	5.5/s	Y	n
11.		Sony RX10	1440	Y	3.0 / 1229	tilting	n	1/3200s	10.0/s	Y	Y
12.		Sony RX10 II	2359	Y	3.0 / 1229	tilting	n	1/3200s	14.0/s	Y	Y
13.		Sony RX10 IV	2359	Y	3.0 / 1440	tilting	Y	1/2000s	24.0/s	Y	Y
14.		Sony RX100	none	n	3.0 / 1229	fixed	n	1/2000s	10.0/s	Y	Y
15.		Sony RX100 II	optional	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
16.		Sony RX100 IV	2359	n	3.0 / 1228	tilting	n	1/2000s	16.0/s	Y	Y
17.		Sony RX100 V	2359	n	3.0 / 1229	tilting	n	1/2000s	24.0/s	Y	Y
Note: *) 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 A5100 has a touchscreen, while the RX10 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 RX10 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).

Concerning the storage of imaging data, both the A5100 and the RX10 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 A5100 and Sony Cyber-shot DSC-RX10 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 A5100	-	stereo / mono	-	-	micro	2.0	Y	Y	-
2.		Sony RX10 III	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
3.		Panasonic FZ2500	Y	stereo / mono	Y	Y	micro	2.0	Y	-	-
4.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
5.		Sony A5000	-	stereo / mono	-	-	micro	2.0	Y	Y	-
6.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
7.		Sony NEX-3	Y	stereo / mono	-	-	mini	2.0	-	-	-
8.		Sony NEX-3N	-	stereo / mono	-	-	micro	2.0	-	-	-
9.		Sony NEX-5T	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
10.		Sony NEX-F3	Y	stereo / mono	-	-	mini	2.0	-	-	-
11.		Sony RX10	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
12.		Sony RX10 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
13.		Sony RX10 IV	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
14.		Sony RX100	-	stereo / mono	-	-	micro	2.0	-	-	-
15.		Sony RX100 II	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
16.		Sony RX100 IV	-	stereo / mono	-	-	micro	2.0	Y	Y	-
17.		Sony RX100 V	-	stereo / mono	-	-	micro	2.0	Y	Y	-

It is notable that the RX10 III has a microphone port, which can help to improve the quality of audio recordings by attaching an external microphone. The A5100 does not feature such a mic input.

Both the A5100 and the RX10 III have been discontinued, but can regularly be found used on ebay. The RX10 III was replaced by the Sony RX10 IV, while the A5100 does not have a direct successor. Further information on the features and operation of the A5100 and RX10 III can be found, respectively, in the Sony A5100 Manual (free pdf) or the online Sony RX10 III Manual.

Review summary

So how do things add up? Which of the two cameras – the Sony A5100 or the Sony RX10 III – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Sony Alpha A5100:

• More detail: Offers more megapixels (24 vs 20MP) with a 10% higher linear resolution.
• Better image quality: Scores markedly higher (10 points) in the DXO overall assessment.
• Better low-light sensitivity: Requires less light for good images (1.5 stops ISO advantage).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster shutter: Has higher mechanical shutter speed (1/4000s vs 1/2000s) to freeze action.
• More flexible: Accepts interchangeable lenses, so that lens characteristics can be altered.
• More compact: Is smaller (110x63mm vs 133x94mm) and thus needs less room in the bag.
• More heavily discounted: Has been on the market for longer (launched in August 2014).

Reasons to prefer the Sony Cyber-shot DSC-RX10 III:

• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• Easier framing: Has an electronic viewfinder for image composition and settings control.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• More detailed LCD: Has a higher resolution rear screen (1229k vs 922k dots).
• Faster burst: Shoots at higher frequency (14 vs 6 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Ready to shoot: Has an integrated lens, whereas the A5100 necessitates an extra lens.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• More modern: Was introduced somewhat (1 year and 7 months) more recently.

If the count of individual advantages (bullet points above) is taken as a guide, the RX10 III emerges as the winner of the match-up (13 : 10 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 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 A5100 and the Sony RX10 III place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best Superzoom 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 partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the A5100 or the RX10 III. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.

Expert reviews

This is where reviews by experts come in. 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 A5100	4.5/5	+	..	..	4.5/5	5/5	Aug 2014	US$ 549	ebay.com
2.		Sony RX10 III	5/5	+	..	84/100	4.5/5	4.5/5	Mar 2016	US$ 1 499	ebay.com
3.		Panasonic FZ2500	..	+	..	82/100	4.5/5	5/5	Sep 2016	US$ 1 199	amazon.com
4.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	US$ 329	ebay.com
5.		Sony A5000	3/5	+	..	..	4.5/5	4.5/5	Jan 2014	US$ 449	ebay.com
6.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	US$ 599	ebay.com
7.		Sony NEX-3	..	..	..	70/100	4.5/5	4/5	May 2010	US$ 599	ebay.com
8.		Sony NEX-3N	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	US$ 499	ebay.com
9.		Sony NEX-5T	..	..	..	..	4.5/5	4.5/5	Aug 2013	US$ 699	ebay.com
10.		Sony NEX-F3	4/5	..	..	74/100	4.5/5	4.5/5	May 2012	US$ 599	ebay.com
11.		Sony RX10	5/5	+	..	80/100	4.5/5	4.5/5	Oct 2013	US$ 1 299	ebay.com
12.		Sony RX10 II	5/5	+ +	..	82/100	4.5/5	4/5	Jun 2015	US$ 1 299	ebay.com
13.		Sony RX10 IV	5/5	+	3.5/5	84/100	4.5/5	5/5	Sep 2017	US$ 1 699	amazon.com
14.		Sony RX100	5/5	+ +	..	78/100	4/5	5/5	Jun 2012	US$ 649	ebay.com
15.		Sony RX100 II	5/5	+ +	..	79/100	4.5/5	4.5/5	Jun 2013	US$ 749	ebay.com
16.		Sony RX100 IV	4.5/5	+ +	..	85/100	4/5	4.5/5	Jun 2015	US$ 999	ebay.com
17.		Sony RX100 V	4.5/5	+ +	..	83/100	4/5	4.5/5	Oct 2016	US$ 999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The assessments were made in relation to similar cameras of the same technological generation. 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, 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 your choice using the following search menu. 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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