Sony RX10 IV vs 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 (A99) sensor. The RX10 IV has a resolution of 20 megapixels, whereas the A99 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 IV		Sony A99
Fixed lens compact camera		Digital single lens reflex
24-600mm f/2.4-4.0		Sony A mount lenses
20 MP – 1" sensor		24 MP – Full Frame sensor
4K/30p Video		1080/60p Video
ISO 100-12,800 (64 - 25,600)		ISO 100-25,600
Electronic viewfinder (2359k dots)		Electronic viewfinder (2359k dots)
3.0" LCD – 1440k dots		3.0" LCD – 1229k dots
Tilting touchscreen		Fully flexible screen (no touchscreen)
24 shutter flaps per second		6 shutter flaps per second
Lens-based stabilization		In-body stabilization
Weathersealed body		Weathersealed body
400 shots per battery charge		500 shots per battery charge
133 x 94 x 145 mm, 1095 g		147 x 111 x 78 mm, 812 g

Check RX10 IV price at
amazon.com
Check A99 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Cyber-shot DSC-RX10 IV and the Sony Alpha SLT-A99? 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 IV and the Sony A99. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth measures are rounded to the nearest millimeter.

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 built 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.

Concerning battery life, the RX10 IV gets 400 shots out of its Sony NP-FW50 battery, while the A99 can take 500 images on a single charge of its Sony NP-FM500H power pack. The power pack in the RX10 IV can be charged via the USB port, so that it is not always necessary to take the battery charger along 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 IV	133 mm	94 mm	145 mm	1095 g	400	Y	Sep 2017	1,699	amazon.com
2.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
3.		Canon G1 X Mark III	115 mm	78 mm	51 mm	399 g	200	Y	Oct 2017	1,299	ebay.com
4.		Fujifilm X-Pro2	141 mm	83 mm	46 mm	495 g	350	Y	Jan 2016	1,699	ebay.com
5.		Panasonic FZ2500	138 mm	102 mm	135 mm	915 g	350	n	Sep 2016	1,199	amazon.com
6.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	4,499	amazon.com
7.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
8.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
9.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	ebay.com
10.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
11.		Sony A6300	120 mm	67 mm	49 mm	404 g	400	Y	Feb 2016	999	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 III	133 mm	94 mm	127 mm	1051 g	420	Y	Mar 2016	1,499	ebay.com
16.		Sony RX100 V	102 mm	58 mm	41 mm	299 g	220	n	Oct 2016	999	ebay.com
17.		Sony RX100 VI	102 mm	58 mm	43 mm	301 g	240	n	Jun 2018	1,199	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

The price is, of course, an important factor in any camera decision. The listed launch 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 built 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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. 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 tend to be more expensive and 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.

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.

The resolution advantage of the Sony A99 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A99 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 IV 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 RX10 IV 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 IV 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 SLT-A99 are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-25600.

In terms of underlying technology, the RX10 IV is build around a BSI-CMOS sensor, while the A99 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 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 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 IV	1-inch	20.0	5472	3648	4K/30p	22.0	12.2	408	63
2.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
3.		Canon G1 X Mark III	APS-C	24.0	6000	4000	1080/60p	23.8	13.2	1649	81
4.		Fujifilm X-Pro2	APS-C	24.0	6000	4000	1080/60p	23.7	13.0	1608	80
5.		Panasonic FZ2500	1-inch	20.0	5472	3648	4K/30p	23.0	12.6	538	70
6.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
7.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
8.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
9.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
10.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
11.		Sony A6300	APS-C	24.0	6000	4000	4K/30p	24.4	13.7	1437	85
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 III	1-inch	20.0	5472	3648	4K/30p	23.1	12.6	472	70
16.		Sony RX100 V	1-inch	20.0	5472	3648	4K/30p	22.8	12.4	586	70
17.		Sony RX100 VI	1-inch	20.0	5472	3648	4K/30p	22.1	12.3	478	64
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras cannot only take still pictures, but also record videos. 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 range 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.

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 IV	2359	Y	3.0 / 1440	tilting	Y	1/2000s	24.0/s	Y	Y
2.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
3.		Canon G1 X Mark III	2360	n	3.0 / 1040	swivel	Y	1/2000s	9.0/s	Y	Y
4.		Fujifilm X-Pro2	2360	n	3.0 / 1620	fixed	n	1/8000s	8.0/s	n	n
5.		Panasonic FZ2500	2360	n	3.0 / 1040	swivel	Y	1/4000s	12.0/s	Y	Y
6.		Sony A9 II	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
7.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
8.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
9.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
10.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
11.		Sony A6300	2359	n	3.0 / 922	tilting	n	1/4000s	11.0/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 III	2359	Y	3.0 / 1229	tilting	n	1/2000s	14.0/s	Y	Y
16.		Sony RX100 V	2359	n	3.0 / 1229	tilting	n	1/2000s	24.0/s	Y	Y
17.		Sony RX100 VI	2359	n	3.0 / 1229	tilting	Y	1/2000s	24.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One difference between the cameras concerns the presence of an on-board flash. The RX10 IV has one, while the A99 does not. While the built-in flash of the RX10 IV is not very powerful, it can at times be useful as a fill-in light.

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 IV 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 IV and the A99 write their files to SDXC or Memory Stick PRO Duo cards. The A99 features dual card slots, which can be very useful in case a memory card fails. In contrast, the RX10 IV only has one slot. 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 IV and Sony Alpha SLT-A99 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 IV	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
2.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
3.		Canon G1 X Mark III	Y	stereo / mono	-	-	micro	2.0	Y	Y	Y
4.		Fujifilm X-Pro2	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
5.		Panasonic FZ2500	Y	stereo / mono	Y	Y	micro	2.0	Y	-	-
6.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
7.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
8.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
9.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-
10.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-
11.		Sony A6300	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
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 III	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony RX100 V	-	stereo / mono	-	-	micro	2.0	Y	Y	-
17.		Sony RX100 VI	-	stereo / mono	-	-	micro	2.0	Y	Y	Y

It is notable that the RX10 IV offers wifi support, while the A99 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Studio photographers will appreciate that the Sony A99 (unlike the RX10 IV) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Travel and landscape photographers will find it useful that the A99 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

The RX10 IV is a recent model that features in the current product line-up of Sony. In contrast, the A99 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the A99 was succeeded by the Sony A99. Further information on the features and operation of the RX10 IV and A99 can be found, respectively, in the Sony RX10 IV Manual (free pdf) or the online Sony A99 Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Sony RX10 IV and the Sony A99? Which camera is better? The listing below highlights the relative strengths of the two models.

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

• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• 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.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Ready to shoot: Comes with a built-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 travel charging: Can be conveniently charged via its USB port.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More affordable: Was introduced at a lower price, despite coming with a built-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%.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.71x vs 0.70x).
• More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/2000s) 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.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More heavily discounted: Has been around for much longer (launched in September 2012).

If the count of relative strengths (bullet points above) is taken as a measure, the RX10 IV emerges as the winner of the contest (14 : 11 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 RX10 IV and the Sony A99 place the cameras among the top in their class? Find out in the latest Best Superzoom Camera and Best DSLR 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 IV and the A99 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 why hands-on reviews by experts are important. 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 (USD)	Street Price
1.		Sony RX10 IV	5/5	+	3.5/5	84/100	4.5/5	5/5	Sep 2017	1,699	amazon.com
2.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
3.		Canon G1 X Mark III	5/5	+	4/5	79/100	4.5/5	4.5/5	Oct 2017	1,299	ebay.com
4.		Fujifilm X-Pro2	..	+	..	83/100	4.5/5	4.5/5	Jan 2016	1,699	ebay.com
5.		Panasonic FZ2500	..	+	..	82/100	4.5/5	5/5	Sep 2016	1,199	amazon.com
6.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	4,499	amazon.com
7.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
8.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
9.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
10.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
11.		Sony A6300	4.5/5	+	..	85/100	5/5	5/5	Feb 2016	999	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 III	5/5	+	..	84/100	4.5/5	4.5/5	Mar 2016	1,499	ebay.com
16.		Sony RX100 V	4.5/5	+ +	..	83/100	4/5	4.5/5	Oct 2016	999	ebay.com
17.		Sony RX100 VI	4.5/5	+ +	..	83/100	4/5	4.5/5	Jun 2018	1,199	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. Thus, a score needs to be put into the context of the launch date and the launch price 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. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Check RX10 IV price at
amazon.com
Check A99 offers at
ebay.com

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 use the search menu below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

~

Check RX10 IV price at
amazon.com
Check A99 offers at
ebay.com

Did you notice an error on this page? If so, please get in touch, so that we can correct the information.