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Sony A7R III versus Sony RX100 III

The Sony Alpha A7R III and the Sony Cyber-shot DSC-RX100 III are two digital cameras that were officially introduced, respectively, in October 2017 and May 2014. The A7R III is a mirrorless interchangeable lens camera, while the RX100 III is a fixed lens compact. The cameras are based on a full frame (A7R III) and an one-inch sensor. The A7R III has a resolution of 42.2 megapixel, whereas the RX100 III provides 20 MP.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Sony A7R III and the Sony RX100 III. Three consecutive perspectives from the front, the top, and the back are presented. All size dimensions are rounded to the nearest millimeter. You can also toggle the display to switch to a percentage comparison if you prefer that the measures are being expressed in relative terms (in this case, the camera on the left – the A7R III – represents the basis or 100 percent across all the size and weight measures).

Sony A7R III vs Sony RX100 III front
A7R III versus RX100 III top view
A7R III and RX100 III rear side
Body view (A7R III on the left)

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 considerably smaller (51 percent) than the Sony A7R III. Cameras intended for semi-professional or professional use tend to be a bit bulkier in order to give them the necessary ruggedness. It is worth mentioning in this context that the A7R III 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 build in, whereas the A7R III is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup. You can find an overview of optics for the A7R III and their specifications in the Sony FE Lens Catalog.

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, just select a new right or left comparator from among the camera models in the table. Alternatively, you can also move across to the CAM-parator tool and choose from the broad selection of possible comparisons there.

Camera Body Specifications
Camera Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(y/n)
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Sony A7R III (⇒ rgt) 127 mm 96 mm 74 mm 650 g 650 YES 2017 3,199 latest check
Sony RX100 III (⇒ lft) 102 mm 58 mm 41 mm 290 g 320 no 2014 799discont. check
Canon M3 (⇒ lft | rgt) 111 mm 68 mm 44 mm 366 g 250 no 2015 679discont. check
Canon G7 X (⇒ lft | rgt) 103 mm 60 mm 40 mm 304 g 210 no 2014 699discont. check
Nikon D850 (⇒ lft | rgt) 146 mm 124 mm 79 mm 1005 g 1840 YES 2017 3,299 latest check
Panasonic FZ1000 (⇒ lft | rgt) 137 mm 99 mm 131 mm 831 g 360 no 2014 899discont. check
Pentax K-1 (⇒ lft | rgt) 137 mm 110 mm 86 mm 1010 g 760 YES 2016 1,799 latest check
Sony A9 (⇒ lft | rgt) 127 mm 96 mm 63 mm 673 g 650 YES 2017 4,499 latest check
Sony A99 II (⇒ lft | rgt) 143 mm 104 mm 76 mm 849 g 490 YES 2016 3,199 latest check
Sony A6500 (⇒ lft | rgt) 120 mm 67 mm 53 mm 453 g 350 YES 2016 1,399 latest check
Sony A7R II (⇒ lft | rgt) 127 mm 96 mm 60 mm 625 g 290 YES 2015 3,199discont. check
Sony A7S II (⇒ lft | rgt) 127 mm 96 mm 60 mm 627 g 370 YES 2015 2,999 latest check
Sony RX100 IV (⇒ lft | rgt) 102 mm 58 mm 41 mm 298 g 280 no 2015 999discont. check
Sony A7 II (⇒ lft | rgt) 127 mm 96 mm 60 mm 599 g 350 YES 2014 1,999 latest check
Sony A7R (⇒ lft | rgt) 127 mm 94 mm 48 mm 465 g 340 YES 2013 2,299discont. check
Sony RX100 II (⇒ lft | rgt) 102 mm 58 mm 38 mm 281 g 350 no 2013 749discont. check
Sony A99 (⇒ lft | rgt) 147 mm 111 mm 78 mm 812 g 500 YES 2012 2,799discont. check

The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The RX100 III was launched at a lower price than the A7R III, despite having a lens build 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

Sensor comparison

The size of the imaging sensor is a crucial determinant of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color depth than smaller pixel-units in a sensor of the same technological generation. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better isolate a subject from the background. On the downside, larger sensors are more costly to manufacture and tent to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A7R III features a full frame sensor and the Sony RX100 III an one-inch sensor. The sensor area in the RX100 III is 87 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 2.7. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Sony A7R III and Sony RX100 III sensor measures
Sensor size

With 42.2MP, the A7R III offers a higher resolution than the RX100 III (20MP), but the A7R III nevertheless has larger individual pixels (pixel pitch of 4.51μm versus 2.41μm for the RX100 III) due to its larger sensor. Moreover, the A7R III is a somewhat more recent model (by 3 years and 5 months) than the RX100 III, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. Coming back to sensor resolution, it should be mentioned that the A7R III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

A7R III versus RX100 III MP
Sensor resolution

Consistent information on actual sensor performance is available from DXO Mark for most 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. 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 Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Sony A7R III (⇒ rgt) Full Frame 42.2 7952 5304 4K/30p .. .. .. ..
Sony RX100 III (⇒ lft) 1-inch 20.0 5472 3648 1080/60p 22.4 12.3 495 67
Canon M3 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/30p 22.8 11.8 1169 72
Canon G7 X (⇒ lft | rgt) 1-inch 20.0 5472 3648 1080/60p 23.0 12.7 556 71
Nikon D850 (⇒ lft | rgt) Full Frame 45.4 8256 5504 4K/30p 26.4 14.8 2660 100
Panasonic FZ1000 (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 22.1 11.7 517 64
Pentax K-1 (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60i 25.4 14.6 3280 96
Sony A9 (⇒ lft | rgt) Full Frame 24.0 6000 4000 4K/30p 24.9 13.3 3517 92
Sony A99 II (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 25.4 13.4 2317 92
Sony A6500 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p 24.5 13.7 1405 85
Sony A7R II (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 26.0 13.9 3434 98
Sony A7S II (⇒ lft | rgt) Full Frame 12.0 4240 2832 4K/30p 23.6 13.3 2993 85
Sony RX100 IV (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 22.8 12.6 591 70
Sony A7 II (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.9 13.6 2449 90
Sony A7R (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60p 25.6 14.1 2746 95
Sony RX100 II (⇒ lft | rgt) 1-inch 20.0 5472 3648 1080/60p 22.5 12.4 483 67
Sony A99 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 25.0 14.0 1555 89

Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A7R III 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

Apart from body and sensor, cameras can and do differ across a variety of features. The two cameras under consideration are similar with respect to both having an electronic viewfinder. However, the one in the A7R III offers a substantially higher resolution than the one in the RX100 III (3686k vs 1440k dots). The following table reports on some other key feature differences and similarities of the Sony A7R III, the Sony RX100 III, and comparable cameras. The full specs-sheets can be found in the camera manual or, for example, in the dpreview camera hub.

Core Features
Camera Viewfinder
(Type or
'000 dots)
Control
Panel
(Y/n)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(Y/n)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec))
Build-in
Flash
(GN)
Build-in
Image
Stab
Sony A7R III (⇒ rgt) 3686 no 3.0 1440 tilting YES 8000 10.0 no YES
Sony RX100 III (⇒ lft) 1440 no 3.0 1229 tilting no 2000 10.0 YES no
Canon M3 (⇒ lft | rgt) no no 3.0 1040 tilting YES 4000 4.2 5 no
Canon G7 X (⇒ lft | rgt) no no 3.0 1040 tilting YES 2000 6.5 7 no
Nikon D850 (⇒ lft | rgt) optical YES 3.2 2359 tilting YES 8000 9.0 no no
Panasonic FZ1000 (⇒ lft | rgt) 2359 no 3.0 921 swivel no 4000 12.0 13.5 no
Pentax K-1 (⇒ lft | rgt) optical YES 3.2 1037 full-flex no 8000 4.4 no YES
Sony A9 (⇒ lft | rgt) 3686 no 3.0 1440 tilting YES 8000 20.0 no YES
Sony A99 II (⇒ lft | rgt) 2400 YES 3.0 1229 tilting no 8000 12.0 no YES
Sony A6500 (⇒ lft | rgt) 2300 no 3.0 922 tilting YES 4000 11.0 6 YES
Sony A7R II (⇒ lft | rgt) 2400 no 3.0 1229 tilting no 8000 5.0 no YES
Sony A7S II (⇒ lft | rgt) 2400 no 3.0 1229 tilting no 8000 5.0 no YES
Sony RX100 IV (⇒ lft | rgt) 2359 no 3.0 1228 tilting no 2000 16.0 10.2 no
Sony A7 II (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no YES
Sony A7R (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 4.0 no no
Sony RX100 II (⇒ lft | rgt) no no 3.0 1229 tilting no 2000 10.0 15 no
Sony A99 (⇒ lft | rgt) 2359 YES 3.0 1229 full-flex no 8000 6.0 no YES

The A7R III is a current model that online retailers, such as amazon, will have in stock. In contrast, the RX100 III has been discontinued (but it 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.

Summary

So how do things add up? Is the Sony A7R III better than the Sony RX100 III or vice versa? The listing below highlights the relative strengths of the two models.


Arguments in favor of the Sony Alpha A7R III:

  • More detail: Offers more megapixels (42.2 vs 20MP) with a 45% higher linear resolution.
  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • Better image quality: Features a larger and more technologically advanced imaging sensor.
  • Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
  • More detailed viewfinder: Has a higher resolution electronic viewfinder (3686k vs 1440k dots).
  • More detailed LCD: Has a higher resolution rear screen (1440k vs 1229k dots).
  • Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
  • Faster shutter: Has a higher mechanical shutter speed (8000/sec vs 2000/sec) to freeze action.
  • More flexible: Accepts interchangeable lenses, so that lens characteristics can be altered.
  • Longer lasting: Can take more shots (650 versus 320) on a single battery charge.
  • Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
  • Sharper images: Has hand-shake reducing image stabilization build-in.
  • More modern: Reflects 3 years and 5 months of technical progress since the RX100 III launch.

Advantages of the Sony Cyber-shot DSC-RX100 III:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Ready to shoot: Has an integrated lens, whereas the A7R III necessitates an extra lens.
  • More compact: Is smaller (102x58mm vs 127x96mm) and will fit more readily into a bag.
  • Less heavy: Has a lower weight even though it has a lens build in (unlike the A7R III).
  • Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
  • More affordable: Was introduced at a lower price, despite coming with a build-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 A7R III is the clear winner of the match-up (13 : 7 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.

A7R III 13:07 RX100 III

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains incomplete and does no justice, for example, to the way the A7R III or the RX100 III handle or 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. This is where reviews by experts come in. The table below summarizes the assessments of some of the best known camera review sites. The full reviews are available, respectively, at cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.

Review scores
Camera camera
labs
dp
review
ephoto
zine
imaging
resource
photography
blog
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Sony A7R III (⇒ rgt) .. .. .. .. .. 2017 3,199 latest check
Sony RX100 III (⇒ lft) HiRec 82/100 Gold 4.5/5 4.5/5 5/5 2014 799discont. check
Canon M3 (⇒ lft | rgt) reviewed 75/100 4.5/5 4.5/5 4/5 2015 679discont. check
Canon G7 X (⇒ lft | rgt) HiRec 77/100 Silver 4.5/5 3.5/5 4.5/5 2014 699discont. check
Nikon D850 (⇒ lft | rgt) .. 89/100 Gold 4.5/5 .. 5/5 2017 3,299 latest check
Panasonic FZ1000 (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 4.5/5 4.5/5 2014 899discont. check
Pentax K-1 (⇒ lft | rgt) - 84/100 Silver 5/5 4.5/5 5/5 2016 1,799 latest check
Sony A9 (⇒ lft | rgt) .. 89/100 Gold 5/5 5/5 5/5 2017 4,499 latest check
Sony A99 II (⇒ lft | rgt) - 85/100 Silver 4.5/5 4.5/5 4.5/5 2016 3,199 latest check
Sony A6500 (⇒ lft | rgt) HiRec 85/100 Silver 4.5/5 5/5 4.5/5 2016 1,399 latest check
Sony A7R II (⇒ lft | rgt) HiRec 90/100 Gold 5/5 4.5/5 5/5 2015 3,199discont. check
Sony A7S II (⇒ lft | rgt) Rec - 4.5/5 5/5 5/5 2015 2,999 latest check
Sony RX100 IV (⇒ lft | rgt) HiRec 85/100 Gold 4/5 4.5/5 4.5/5 2015 999discont. check
Sony A7 II (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 5/5 2014 1,999 latest check
Sony A7R (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 5/5 5/5 2013 2,299discont. check
Sony RX100 II (⇒ lft | rgt) HiRec 79/100 Silver 4.5/5 5/5 4.5/5 2013 749discont. check
Sony A99 (⇒ lft | rgt) - 84/100 Gold 4.5/5 reviewed 4.5/5 2012 2,799discont. check

The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. A score, therefore, has to be seen in close connection to the price and market introduction time 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. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Other comparisons

If you would like to see a different side-by-side camera review, just use the search menu below. An an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool. If the camera you are interested in is not available, kindly get in touch, and I will try to add information on that model to the database.

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