Sony RX10 III vs A5100

The Sony Cyber-shot DSC-RX10 III and the Sony Alpha A5100 are two digital cameras that were announced, respectively, in March 2016 and August 2014. The RX10 III is a fixed lens compact, while the A5100 is a mirrorless interchangeable lens camera. The cameras are based on an one-inch (RX10 III) and an APS-C (A5100) sensor. The RX10 III has a resolution of 20 megapixels, whereas the A5100 provides 24 MP.

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

Headline Specifications

Sony RX10 III		Sony A5100
Fixed lens compact camera		Mirrorless system camera
24-600mm f/2.4-4.0		Sony E mount lenses
20 MP – 1" sensor		24 MP – APS-C sensor
4K/30p Video		1080/60p Video
ISO 100-12,800 (64 - 25,600)		ISO 100-25,600
Electronic viewfinder (2359k dots)		No viewfinder, LCD framing
3.0" LCD – 1229k dots		3.0" LCD – 922k dots
Tilting screen (no touchscreen)		Tilting touchscreen
14 shutter flaps per second		6 shutter flaps per second
Weathersealed body		not weather sealed
420 shots per battery charge		400 shots per battery charge
133 x 94 x 127 mm, 1051 g		110 x 63 x 36 mm, 283 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Cyber-shot DSC-RX10 III and the Sony Alpha A5100? 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 RX10 III and the Sony A5100. 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.

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 A5100 is considerably smaller (45 percent) than the Sony RX10 III. It is worth mentioning in this context that the RX10 III is splash and dust resistant, 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 following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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 RX10 III	133 mm	94 mm	127 mm	1051 g	420	Y	Mar 2016	1,499	ebay.com
2.		Sony A5100	110 mm	63 mm	36 mm	283 g	400	n	Aug 2014	549	ebay.com
3.		Canon 7D II	149 mm	112 mm	78 mm	910 g	670	Y	Sep 2014	1,799	ebay.com
4.		Canon G3 X	123 mm	77 mm	105 mm	733 g	300	Y	Jun 2015	999	ebay.com
5.		Nikon D500	147 mm	115 mm	81 mm	860 g	1240	Y	Jan 2016	1,999	ebay.com
6.		Panasonic FZ2500	138 mm	102 mm	135 mm	915 g	350	n	Sep 2016	1,199	amazon.com
7.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	329	ebay.com
8.		Sony A5000	110 mm	63 mm	36 mm	269 g	420	n	Jan 2014	449	ebay.com
9.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	599	ebay.com
10.		Sony NEX-3	117 mm	62 mm	33 mm	297 g	330	n	May 2010	599	ebay.com
11.		Sony NEX-3N	110 mm	62 mm	35 mm	269 g	480	n	Feb 2013	499	ebay.com
12.		Sony RX0	59 mm	41 mm	30 mm	110 g	240	Y	Aug 2017	699	ebay.com
13.		Sony RX10	129 mm	88 mm	102 mm	813 g	420	Y	Oct 2013	1,299	ebay.com
14.		Sony RX10 II	129 mm	88 mm	102 mm	813 g	400	Y	Jun 2015	1,299	ebay.com
15.		Sony RX10 IV	133 mm	94 mm	145 mm	1095 g	400	Y	Sep 2017	1,699	amazon.com
16.		Sony RX100 IV	102 mm	58 mm	41 mm	298 g	280	n	Jun 2015	999	ebay.com
17.		Sony RX100 V	102 mm	58 mm	41 mm	299 g	220	n	Oct 2016	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 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. 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 RX10 III features an one-inch sensor and the Sony A5100 an APS-C sensor. The sensor area in the A5100 is 216 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.7 and 1.5. 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 pixel-units.

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 Cyber-shot DSC-RX10 III has a native sensitivity range from ISO 100 to ISO 12800, which can be extended to ISO 64-25600. The corresponding ISO settings for the Sony Alpha A5100 are ISO 100 to ISO 25600 (no boost).

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

For many cameras, data on sensor performance has been reported by DXO Mark. 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"). Of the two cameras under consideration, the A5100 has a markedly higher DXO score than the RX10 III (overall score 10 points higher), which will translate into better image quality. The 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 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 RX10 III	1-inch	20.0	5472	3648	4K/30p	23.1	12.6	472	70
2.		Sony A5100	APS-C	24.0	6000	4000	1080/60p	23.8	12.7	1347	80
3.		Canon 7D II	APS-C	20.0	5472	3648	1080/60p	22.4	11.8	1082	70
4.		Canon G3 X	1-inch	20.0	5472	3648	1080/60p	21.4	12.3	521	63
5.		Nikon D500	APS-C	20.7	5568	3712	4K/30p	24.0	14.0	1324	83
6.		Panasonic FZ2500	1-inch	20.0	5472	3648	4K/30p	23.0	12.6	538	70
7.		Sony A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
8.		Sony A5000	APS-C	19.8	5456	3632	1080/60i	23.8	13.0	1089	79
9.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
10.		Sony NEX-3	APS-C	14.0	4592	3056	720/30p	22.1	12.0	830	68
11.		Sony NEX-3N	APS-C	16.0	4912	3264	1080/60i	22.8	12.5	1067	74
12.		Sony RX0	1-inch	15.4	4800	3200	1080/60p	22.4	12.4	548	68
13.		Sony RX10	1-inch	20.0	5472	3648	1080/60p	22.9	12.6	474	69
14.		Sony RX10 II	1-inch	20.0	5472	3648	4K/30p	23.0	12.6	531	70
15.		Sony RX10 IV	1-inch	20.0	5472	3648	4K/30p	22.0	12.2	408	63
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 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 RX10 III provides a higher video resolution than the A5100. It can shoot video footage at 4K/30p, while the A5100 is limited to 1080/60p.

Feature comparison

Apart from 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 adjacent table lists some of the other core features of the Sony RX10 III and Sony A5100 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 RX10 III	2359	Y	3.0 / 1229	tilting	n	1/2000s	14.0/s	Y	Y
2.		Sony A5100	none	n	3.0 / 922	tilting	Y	1/4000s	6.0/s	Y	n
3.		Canon 7D II	optical	Y	3.0 / 1040	fixed	n	1/8000s	10.0/s	Y	n
4.		Canon G3 X	optional	n	3.2 / 1620	tilting	Y	1/2000s	5.9/s	Y	Y
5.		Nikon D500	optical	Y	3.2 / 2359	tilting	Y	1/8000s	10.0/s	n	n
6.		Panasonic FZ2500	2360	n	3.0 / 1040	swivel	Y	1/4000s	12.0/s	Y	Y
7.		Sony A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
8.		Sony A5000	none	n	3.0 / 461	tilting	n	1/4000s	3.5/s	Y	n
9.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
10.		Sony NEX-3	optional	n	3.0 / 920	tilting	n	1/4000s	7.0/s	n	n
11.		Sony NEX-3N	optional	n	3.0 / 460	tilting	n	1/4000s	4.0/s	Y	n
12.		Sony RX0	none	n	1.5 / 230	fixed	n	..	5.5/s	n	n
13.		Sony RX10	1440	Y	3.0 / 1229	tilting	n	1/3200s	10.0/s	Y	Y
14.		Sony RX10 II	2359	Y	3.0 / 1229	tilting	n	1/3200s	14.0/s	Y	Y
15.		Sony RX10 IV	2359	Y	3.0 / 1440	tilting	Y	1/2000s	24.0/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 feature that is present on the RX10 III, but is missing on the A5100 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 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 RX10 III and the A5100 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 Cyber-shot DSC-RX10 III and Sony Alpha A5100 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 RX10 III	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
2.		Sony A5100	-	stereo / mono	-	-	micro	2.0	Y	Y	-
3.		Canon 7D II	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
4.		Canon G3 X	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
5.		Nikon D500	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
6.		Panasonic FZ2500	Y	stereo / mono	Y	Y	micro	2.0	Y	-	-
7.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
8.		Sony A5000	-	stereo / mono	-	-	micro	2.0	Y	Y	-
9.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
10.		Sony NEX-3	Y	stereo / mono	-	-	mini	2.0	-	-	-
11.		Sony NEX-3N	-	stereo / mono	-	-	micro	2.0	-	-	-
12.		Sony RX0	-	stereo / mono	Y	-	micro	2.0	Y	-	Y
13.		Sony RX10	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
14.		Sony RX10 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony RX10 IV	Y	stereo / mono	Y	Y	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 hotshoe, while the A5100 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.

Both the RX10 III and the A5100 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 RX10 III and A5100 can be found, respectively, in the Sony RX10 III Manual (free pdf) or the online Sony A5100 Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Sony RX10 III or the Sony A5100 – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.

Arguments in favor of 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 an LCD display on top to control 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 a lens built-in, whereas the A5100 requires a separate lens.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• More modern: Is somewhat more recent (announced 1 year and 7 months after the A5100).

Advantages of the Sony Alpha A5100:

• More detail: Has more megapixels (24 vs 20MP), which boosts linear resolution by 10%.
• Better image quality: Scores markedly higher (10 points) in the DXO overall evaluation.
• Better low-light sensitivity: Can shoot in dim conditions (1.5 stops ISO advantage).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• 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: Takes interchangeable lenses and can thus be used with specialty optics.
• More compact: Is smaller (110x63mm vs 133x94mm) and will fit more readily into a bag.
• More heavily discounted: Has been on the market for longer (launched in August 2014).

If the number of relative strengths (bullet points above) is taken as a guide, the RX10 III emerges as the winner of the contest (13 : 10 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 RX10 III and the Sony A5100 place the cameras among the top in their class? Find out in the latest Best Superzoom 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 says little about, for example, the shooting experience and imaging performance of the RX10 III and the A5100 in practical situations. 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 following table reports the overall ratings of the cameras as published by some of the major 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 (USD)	Street Price
1.		Sony RX10 III	5/5	+	..	84/100	4.5/5	4.5/5	Mar 2016	1,499	ebay.com
2.		Sony A5100	4.5/5	+	..	..	4.5/5	5/5	Aug 2014	549	ebay.com
3.		Canon 7D II	4.5/5	+	3.5/5	84/100	4/5	4.5/5	Sep 2014	1,799	ebay.com
4.		Canon G3 X	3.5/5	+	..	..	4.5/5	4/5	Jun 2015	999	ebay.com
5.		Nikon D500	5/5	+ +	4.7/5	91/100	4.5/5	5/5	Jan 2016	1,999	ebay.com
6.		Panasonic FZ2500	..	+	..	82/100	4.5/5	5/5	Sep 2016	1,199	amazon.com
7.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	329	ebay.com
8.		Sony A5000	3/5	+	..	..	4.5/5	4.5/5	Jan 2014	449	ebay.com
9.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	599	ebay.com
10.		Sony NEX-3	..	..	..	70/100	4.5/5	4/5	May 2010	599	ebay.com
11.		Sony NEX-3N	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	499	ebay.com
12.		Sony RX0	..	..	..	..	3.5/5	4/5	Aug 2017	699	ebay.com
13.		Sony RX10	5/5	+	..	80/100	4.5/5	4.5/5	Oct 2013	1,299	ebay.com
14.		Sony RX10 II	5/5	+ +	..	82/100	4.5/5	4/5	Jun 2015	1,299	ebay.com
15.		Sony RX10 IV	5/5	+	3.5/5	84/100	4.5/5	5/5	Sep 2017	1,699	amazon.com
16.		Sony RX100 IV	4.5/5	+ +	..	85/100	4/5	4.5/5	Jun 2015	999	ebay.com
17.		Sony RX100 V	4.5/5	+ +	..	83/100	4/5	4.5/5	Oct 2016	999	ebay.com
Note: (+ +) 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 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.

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Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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