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Sony RX10 IV versus Sony A99

The Sony Cyber-shot DSC-RX10 IV and the Sony Alpha SLT-A99 are two digital cameras that were revealed to the public, respectively, in September 2017 and September 2012. The RX10 IV is a fixed lens compact, while the A99 is a DSLR. The cameras are based on an one-inch (RX10 IV) and a full frame sensor. The RX10 IV has a resolution of 20 megapixel, whereas the A99 provides 24 MP.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Sony RX10 IV and the Sony A99. Three successive views from the front, the top, and the rear are shown. All width, height and depth measures 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 RX10 IV – represents the basis for the calculations across all the size and weight measures).

Sony RX10 IV vs Sony A99 front
RX10 IV versus A99 top view
RX10 IV and A99 rear side
Body view (RX10 IV 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 A99 is notably larger (31 percent) than the Sony RX10 IV. 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 A99 is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.

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 RX10 IV (⇒ rgt) 133 mm 94 mm 145 mm 1095 g 400 YES 2017 1,699 latest check
Sony A99 (⇒ lft) 147 mm 111 mm 78 mm 812 g 500 YES 2012 2,799discont. check
Canon G1 X Mark III (⇒ lft | rgt) 115 mm 78 mm 51 mm 399 g 200 YES 2017 1,299 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
Pentax K-3 (⇒ lft | rgt) 131 mm 100 mm 77 mm 800 g 560 YES 2013 1,299discont. 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 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 RX100 V (⇒ lft | rgt) 102 mm 58 mm 41 mm 299 g 220 no 2016 999 latest check
Sony RX10 II (⇒ lft | rgt) 129 mm 88 mm 102 mm 813 g 400 YES 2015 1,299discont. check
Sony A7 (⇒ lft | rgt) 127 mm 94 mm 48 mm 474 g 340 YES 2013 1,699discont. check
Sony A77 (⇒ lft | rgt) 143 mm 104 mm 81 mm 732 g 470 YES 2011 1,999discont. check
Sony A900 (⇒ lft | rgt) 156 mm 117 mm 82 mm 895 g 880 YES 2008 2,999discont. 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 A99, 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. 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 are more costly to manufacture and tent to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony RX10 IV features an one-inch sensor and the Sony A99 a full frame sensor. The sensor area in the A99 is 634 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.7 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Sony RX10 IV and Sony A99 sensor measures
Sensor size

With 24MP, the A99 offers a higher resolution than the RX10 IV (20MP), but the A99 nevertheless has larger individual pixels (pixel pitch of 5.96μm versus 2.41μm for the RX10 IV) due to its larger sensor. However, the RX10 IV is a much more recent model (by 5 years) than the A99, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units.

RX10 IV versus A99 MP
Sensor resolution

For most cameras, data on sensor performance has been reported by DXO Mark. 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 RX10 IV (⇒ rgt) 1-inch 20.0 5472 3648 4K/30p .. .. .. ..
Sony A99 (⇒ lft) Full Frame 24.0 6000 4000 1080/60p 25.0 14.0 1555 89
Canon G1 X Mark III (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p .. .. .. ..
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
Pentax K-3 (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i 23.7 13.4 1216 80
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 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 RX100 V (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 22.8 12.4 586 70
Sony RX10 II (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 23.0 12.6 531 70
Sony A7 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.8 14.2 2248 90
Sony A77 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24 13.2 801 78
Sony A900 (⇒ lft | rgt) Full Frame 24.4 6048 4032 no 23.7 12.3 1431 79

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 RX10 IV provides a higher video resolution than the A99. It can shoot video footage at 4K/30p, while the A99 is limited to 1080/60p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The RX10 IV and the A99 are similar in the sense that both feature an electronic viewfinder, which is helpful when framing images in bright sunlight. Moreover, their viewfinders offer an identical resolution of 2359k dots. The following table reports on some other key feature differences and similarities of the Sony RX10 IV, the Sony A99, 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 RX10 IV (⇒ rgt) 2359 YES 3.0 1440 tilting YES 2000 24.0 10.8 YES
Sony A99 (⇒ lft) 2359 YES 3.0 1229 full-flex no 8000 6.0 no YES
Canon G1 X Mark III (⇒ lft | rgt) 2360 no 3.0 1040 swivel YES 2000 9.0 9 YES
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
Pentax K-3 (⇒ lft | rgt) optical YES 3.2 1037 fixed no 8000 8.3 13 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 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 YES
Sony RX100 V (⇒ lft | rgt) 2359 no 3.0 1229 tilting no 2000 24.0 10.2 YES
Sony RX10 II (⇒ lft | rgt) 2359 YES 3.0 1229 tilting no 3200 14.0 10.2 YES
Sony A7 (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no no
Sony A77 (⇒ lft | rgt) 2359 YES 3.0 921 full-flex no 8000 12.0 12 YES
Sony A900 (⇒ lft | rgt) optical YES 3.0 922 fixed no 8000 5.0 no YES

The RX10 IV is a current model that online retailers, such as amazon, will have in stock. In contrast, the A99 has been discontinued (but it can be found pre-owned on ebay). As a replacement in the same line of cameras, the A99 was succeeded by the Sony A99 II.

Summary

So what conclusions can be drawn? Is there a clear favorite between the Sony RX10 IV and the Sony RX10 IV? A synthesis of the relative strong points of each of the models is listed below.


Arguments in favor of the Sony Cyber-shot DSC-RX10 IV:

  • Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
  • 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 burst: Shoots at higher frequency (24 vs 6 flaps/sec) to capture the decisive moment.
  • Ready to shoot: Comes with a build-in lens, while the A99 requires a separate lens.
  • More compact: Is smaller (133x94mm vs 147x111mm) and thus needs less room in the bag.
  • Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
  • More affordable: Was introduced at a lower price, despite coming with a build-in lens.
  • More modern: Reflects 5 years of technical progress since the A99 launch.

Reasons to prefer the Sony Alpha SLT-A99:

  • More detail: Has more megapixels (24 vs 20MP), which boosts linear resolution by 10%.
  • More flexible LCD: Has full-flex screen for odd-angle shots in portrait or landscape orientation.
  • Faster shutter: Has higher mechanical shutter speed (8000/sec vs 2000/sec) to freeze action.
  • More flexible: Makes it possible to change lenses and thus to use specialty optics.
  • Longer lasting: Gets more shots (500 versus 400) out of a single battery charge.
  • Sharper images: Has stabilization technology build-in to reduce the impact of hand-shake.
  • More heavily discounted: Has been around for much longer (launched in September 2012).

If the number of relative strengths (bullet points above) is taken as a guide, the RX10 IV emerges as the winner of the contest (9 : 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.

RX10 IV 09:07 A99

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the RX10 IV or the A99. 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 where reviews by experts come in. The following table reports the overall rankings of the cameras as published by some of the major 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 RX10 IV (⇒ rgt) Rec 84/100 Gold 4.5/5 .. 5/5 2017 1,699 latest check
Sony A99 (⇒ lft) - 84/100 Gold 4.5/5 reviewed 4.5/5 2012 2,799discont. check
Canon G1 X Mark III (⇒ lft | rgt) .. 79/100 4.5/5 .. 4.5/5 2017 1,299 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
Pentax K-3 (⇒ lft | rgt) - 83/100 Gold 5/5 4.5/5 5/5 2013 1,299discont. 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 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 RX100 V (⇒ lft | rgt) HiRec 83/100 Silver 4/5 5/5 4.5/5 2016 999 latest check
Sony RX10 II (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 4.5/5 4/5 2015 1,299discont. check
Sony A7 (⇒ lft | rgt) HiRec 80/100 Silver 5/5 4.5/5 5/5 2013 1,699discont. check
Sony A77 (⇒ lft | rgt) 91/100 81/100 Silver - 4.5/5 5/5 2011 1,999discont. check
Sony A900 (⇒ lft | rgt) 90/100 HiRec HiRec 4.5/5 4/5 5/5 2008 2,999discont. check

The above review scores should be interpreted with care, though. The ratings are only valid when refering to cameras in the same category and of the same age. 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, please note that some of the review sites have changed their methodology and reporting over time.

Other comparisons

If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes below. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting. If you cannot find the camera you are interested in, kindly get in touch, and I will try to add information on that model to the database.

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