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Sony A9 versus Sony RX10 IV

The Sony Alpha A9 and the Sony Cyber-shot DSC-RX10 IV are two digital cameras that were announced, respectively, in April 2017 and September 2017. The A9 is a mirrorless interchangeable lens camera, while the RX10 IV is a fixed lens compact. The cameras are based on a full frame (A9) and an one-inch sensor. The A9 has a resolution of 24 megapixel, whereas the RX10 IV provides 20 MP.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Sony A9 and the Sony RX10 IV. 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. You can also use the toggle button 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 side – the A9 – represents the basis for the calculations across all the size and weight measures).

Sony A9 vs Sony RX10 IV front
A9 versus RX10 IV top view
A9 and RX10 IV rear side
Body view (A9 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 RX10 IV is somewhat larger (3 percent) than the Sony A9. 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 and possibly misleading, as the RX10 IV has a lens build in, whereas the A9 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 A9 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 A9 (⇒ rgt) 127 mm 96 mm 63 mm 673 g 650 YES 2017 4,499 latest check
Sony RX10 IV (⇒ lft) 133 mm 94 mm 145 mm 1095 g 400 YES 2017 1,699 latest check
Fujifilm X-Pro2 (⇒ lft | rgt) 141 mm 83 mm 46 mm 495 g 350 YES 2016 1,699 latest check
Fujifilm X-T2 (⇒ lft | rgt) 133 mm 92 mm 49 mm 507 g 340 YES 2016 1,599 latest check
Nikon D500 (⇒ lft | rgt) 147 mm 115 mm 81 mm 860 g 1240 YES 2016 1,999 latest check
Olympus E-M1 II (⇒ lft | rgt) 134 mm 91 mm 67 mm 574 g 440 YES 2016 1,999 latest check
Panasonic GH5 (⇒ lft | rgt) 139 mm 98 mm 87 mm 725 g 410 YES 2017 1,999 latest check
Sony A99 II (⇒ lft | rgt) 143 mm 104 mm 76 mm 849 g 490 YES 2016 3,199 latest check
Sony A6300 (⇒ lft | rgt) 120 mm 67 mm 49 mm 404 g 400 YES 2016 999discont. check
Sony A6500 (⇒ lft | rgt) 120 mm 67 mm 53 mm 453 g 350 YES 2016 1,399 latest check
Sony RX10 III (⇒ lft | rgt) 133 mm 94 mm 127 mm 1051 g 420 YES 2016 1,499discont. 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 A7 II (⇒ lft | rgt) 127 mm 96 mm 60 mm 599 g 350 YES 2014 1,999 latest check
Sony A7 (⇒ lft | rgt) 127 mm 94 mm 48 mm 474 g 340 YES 2013 1,699discont. 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 RX10 IV was launched at a lower price than the A9, 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 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. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the 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 A9 features a full frame sensor and the Sony RX10 IV an one-inch sensor. The sensor area in the RX10 IV is 86 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 A9 and Sony RX10 IV sensor measures
Sensor size
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Sensor size

With 24MP, the A9 offers a higher resolution than the RX10 IV (20MP), but the A9 nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 2.41μm for the RX10 IV) due to its larger sensor. However, the RX10 IV is a somewhat more recent model (by 4 months) than the A9, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels.

A9 versus RX10 IV MP
Sensor resolution
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Sensor resolution

Consistent information on actual sensor performance is available from DXO Mark for most cameras. 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"). 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 Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Sony A9 (⇒ rgt) Full Frame 24.0 6000 4000 4K/30p 24.9 13.3 3517 92
Sony RX10 IV (⇒ lft) 1-inch 20.0 5472 3648 4K/30p .. .. .. ..
Fujifilm X-Pro2 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p - - - -
Fujifilm X-T2 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p - - - -
Nikon D500 (⇒ lft | rgt) APS-C 20.7 5568 3712 4K/30p 24.0 14.0 1324 83
Olympus E-M1 II (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/30p 23.7 12.8 1312 80
Panasonic GH5 (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/60p 23.9 13.0 807 77
Sony A99 II (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 25.4 13.4 2317 92
Sony A6300 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p 24.4 13.7 1437 85
Sony A6500 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p 24.5 13.7 1405 85
Sony RX10 III (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 23.1 12.6 472 70
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 A7 II (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.9 13.6 2449 90
Sony A7 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.8 14.2 2248 90
Sony A99 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 25.0 14.0 1555 89

Many modern cameras cannot only take still pictures, but also record videos. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, and both provide the same movie specifications (4K/30p).

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 A9 offers a substantially higher resolution than the one in the RX10 IV (3686k vs 2359k dots). The adjacent table lists some of the other core features of the Sony A9 and Sony RX10 IV along with similar information for a selection of comparators. If needed, the dpreview camera hub, for example, contains further detail on the cameras' specs.

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 A9 (⇒ rgt) 3686 no 3.0 1440 tilting YES 8000 20.0 no YES
Sony RX10 IV (⇒ lft) 2359 YES 3.0 1440 tilting YES 2000 24.0 10.8 no
Fujifilm X-Pro2 (⇒ lft | rgt) 2360 no 3.0 1620 fixed no 8000 8.0 no no
Fujifilm X-T2 (⇒ lft | rgt) 2360 no 3.0 1040 tilting no 8000 14.0 no no
Nikon D500 (⇒ lft | rgt) optical YES 3.2 2359 tilting YES 8000 10.0 no no
Olympus E-M1 II (⇒ lft | rgt) 2360 no 3.0 1037 swivel YES 8000 18.0 no YES
Panasonic GH5 (⇒ lft | rgt) 3680 no 3.2 1620 swivel YES 8000 12.0 no YES
Sony A99 II (⇒ lft | rgt) 2400 YES 3.0 1229 tilting no 8000 12.0 no YES
Sony A6300 (⇒ lft | rgt) 2300 no 3.0 922 tilting no 4000 11.0 6 no
Sony A6500 (⇒ lft | rgt) 2300 no 3.0 922 tilting YES 4000 11.0 6 YES
Sony RX10 III (⇒ lft | rgt) 2359 YES 3.0 1229 tilting no 2000 14.0 10.8 no
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 A7 II (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no YES
Sony A7 (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no no
Sony A99 (⇒ lft | rgt) 2359 YES 3.0 1229 full-flex no 8000 6.0 no YES

Both the A9 and the RX10 IV are current models that good online retailers will have in stock. You can check the latest prices, for example, at amazon. The RX10 IV replaced the earlier Sony RX10 III, while the A9 does not have a direct predecessor.

Summary

So how do things add up? Which of the two cameras – the Sony A9 or the Sony RX10 IV – has the upper hand? A synthesis of the relative strong points of each of the models is listed below.


Arguments in favor of the Sony Alpha A9:

  • More detail: Offers more megapixels (24 vs 20MP) with a 10% higher linear resolution.
  • Better low-light imaging: Features bigger pixels on a larger sensor for better high-ISO images.
  • More detailed viewfinder: Has higher resolution electronic viewfinder (3686k vs 2359k dots).
  • Faster shutter: Has 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 400) on a single battery charge.
  • Sharper images: Has hand-shake reducing image stabilization build-in.
  • More heavily discounted: Has been on the market for longer (launched in April 2017).

Advantages of the Sony Cyber-shot DSC-RX10 IV:

  • Easier setting verification: Has a control panel on top to check shooting parameters.
  • Ready to shoot: Has an integrated lens, whereas the A9 necessitates an extra lens.
  • 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 modern: Was introduced somewhat (4 months) more recently.

If the count of individual advantages (bullet points above) is taken as a guide, the A9 emerges as the winner of the contest (8 : 5 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features.

A9 08:05 RX10 IV

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the A9 and the RX10 IV 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. This is why expert reviews are important. The table below summarizes the assessments of some of the best known camera review sites. The detailed reviews can be accessed, respectively, on the websites of 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 A9 (⇒ rgt) .. 89/100 Gold 5/5 5/5 5/5 2017 4,499 latest check
Sony RX10 IV (⇒ lft) Rec 84/100 Gold 4.5/5 .. 5/5 2017 1,699 latest check
Fujifilm X-Pro2 (⇒ lft | rgt) Rec 83/100 Silver 4.5/5 4.5/5 4.5/5 2016 1,699 latest check
Fujifilm X-T2 (⇒ lft | rgt) HiRec 86/100 Gold 4.5/5 5/5 5/5 2016 1,599 latest check
Nikon D500 (⇒ lft | rgt) HiRec 91/100 Gold 4.5/5 5/5 5/5 2016 1,999 latest check
Olympus E-M1 II (⇒ lft | rgt) HiRec 85/100 Gold 4.5/5 5/5 4.5/5 2016 1,999 latest check
Panasonic GH5 (⇒ lft | rgt) HiRec 85/100 Gold 4.5/5 5/5 5/5 2017 1,999 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 A6300 (⇒ lft | rgt) Rec 85/100 Gold 5/5 5/5 5/5 2016 999discont. check
Sony A6500 (⇒ lft | rgt) HiRec 85/100 Silver 4.5/5 5/5 4.5/5 2016 1,399 latest check
Sony RX10 III (⇒ lft | rgt) Rec 84/100 Silver 4.5/5 4.5/5 4.5/5 2016 1,499discont. 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 A7 II (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 5/5 2014 1,999 latest check
Sony A7 (⇒ lft | rgt) HiRec 80/100 Silver 5/5 4.5/5 5/5 2013 1,699discont. check
Sony A99 (⇒ lft | rgt) - 84/100 Gold 4.5/5 reviewed 4.5/5 2012 2,799discont. check

The review scores listed above should be treated with care, though. The ratings are only valid when refering to cameras in the same category and of the same age. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Other comparisons

In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. 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 you cannot find the camera you are interested in, please contact me, and I will try to locate and add the respective data to the application.

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