Sony A99 vs RX10 IV

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

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

Headline Specifications

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

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

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha SLT-A99 and the Sony Cyber-shot DSC-RX10 IV? 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

An illustration of the physical size and weight of the Sony A99 and the Sony RX10 IV is provided in the side-by-side display below. The two cameras are presented according to their relative size. 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.

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 notably smaller (23 percent) than the Sony A99. 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 A99 gets 500 shots out of its NP-FM500H battery, while the RX10 IV can take 400 images on a single charge of its NP-FW50 power pack. The power pack in the RX10 IV can be charged via the USB port, which can be very convenient when travelling.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. In case you want to display and compare another camera duo, you can use the CAM-parator app to select your camera combination among a large number of options.

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 A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
2.		Sony RX10 IV	133 mm	94 mm	145 mm	1095 g	400	Y	Sep 2017	1,699	amazon.com
3.		Canon R6	138 mm	98 mm	88 mm	680 g	360	Y	Jul 2020	2,499	amazon.com
4.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	4,499	amazon.com
5.		Sony RX100 VI	102 mm	58 mm	43 mm	301 g	240	n	Jun 2018	1,199	ebay.com
6.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	3,199	ebay.com
7.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
8.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
9.		Sony RX10 III	133 mm	94 mm	127 mm	1051 g	420	Y	Mar 2016	1,499	ebay.com
10.		Sony RX100 V	102 mm	58 mm	41 mm	299 g	220	n	Oct 2016	999	ebay.com
11.		Sony A7R II	127 mm	96 mm	60 mm	625 g	290	Y	Jun 2015	3,199	ebay.com
12.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
13.		Sony RX10 II	129 mm	88 mm	102 mm	813 g	400	Y	Jun 2015	1,299	ebay.com
14.		Sony RX10	129 mm	88 mm	102 mm	813 g	420	Y	Oct 2013	1,299	ebay.com
15.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
16.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	ebay.com
17.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	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. 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.

Sensor comparison

The size of the sensor inside a digital camera is one of the key determinants 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. 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 A99 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.

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 further enhance the light gathering capacity of its pixels.

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 Alpha SLT-A99 has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 50-25600. The corresponding ISO settings for the Sony Cyber-shot DSC-RX10 IV are ISO 100 to ISO 12800, with the possibility to increase the ISO range to 64-25600.

In terms of underlying technology, the A99 is build around a CMOS sensor, while the RX10 IV uses a BSI-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"). 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 A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
2.		Sony RX10 IV	1-inch	20.0	5472	3648	4K/30p	22.0	12.2	408	63
3.		Canon R6	Full Frame	20.0	5472	3648	4k/60p	24.2	14.3	3394	90
4.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
5.		Sony RX100 VI	1-inch	20.0	5472	3648	4K/30p	22.1	12.3	478	64
6.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
7.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
8.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
9.		Sony RX10 III	1-inch	20.0	5472	3648	4K/30p	23.1	12.6	472	70
10.		Sony RX100 V	1-inch	20.0	5472	3648	4K/30p	22.8	12.4	586	70
11.		Sony A7R II	Full Frame	42.2	7952	5304	4K/30p	26.0	13.9	3434	98
12.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
13.		Sony RX10 II	1-inch	20.0	5472	3648	4K/30p	23.0	12.6	531	70
14.		Sony RX10	1-inch	20.0	5472	3648	1080/60p	22.9	12.6	474	69
15.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
16.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
17.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
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. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the RX10 IV provides a better video resolution than the A99. It can shoot movie 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 A99 and the RX10 IV 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 A99, the Sony RX10 IV, 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 A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
2.		Sony RX10 IV	2359	Y	3.0 / 1440	tilting	Y	1/2000s	24.0/s	Y	Y
3.		Canon R6	3690	n	3.0 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
4.		Sony A9 II	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
5.		Sony RX100 VI	2359	n	3.0 / 1229	tilting	Y	1/2000s	24.0/s	Y	Y
6.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
7.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
8.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
9.		Sony RX10 III	2359	Y	3.0 / 1229	tilting	n	1/2000s	14.0/s	Y	Y
10.		Sony RX100 V	2359	n	3.0 / 1229	tilting	n	1/2000s	24.0/s	Y	Y
11.		Sony A7R II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
12.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
13.		Sony RX10 II	2359	Y	3.0 / 1229	tilting	n	1/3200s	14.0/s	Y	Y
14.		Sony RX10	1440	Y	3.0 / 1229	tilting	n	1/3200s	10.0/s	Y	Y
15.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
16.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
17.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
Notes: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The RX10 IV has a touchscreen, while the A99 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

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 A99 and the RX10 IV 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 Alpha SLT-A99 and Sony Cyber-shot DSC-RX10 IV 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 A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
2.		Sony RX10 IV	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
3.		Canon R6	Y	mono / mono	Y	Y	micro	3.2	Y	-	Y
4.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
5.		Sony RX100 VI	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
6.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
7.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
8.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
9.		Sony RX10 III	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
10.		Sony RX100 V	-	stereo / mono	-	-	micro	2.0	Y	Y	-
11.		Sony A7R II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
12.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
13.		Sony RX10 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
14.		Sony RX10	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-
17.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-

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

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 A99 and RX10 IV can be found, respectively, in the Sony A99 Manual (free pdf) or the online Sony RX10 IV Manual.

Review summary

So how do things add up? Is the Sony A99 better than the Sony RX10 IV or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Sony Alpha SLT-A99:

• More detail: Offers more megapixels (24 vs 20MP) with a 10% higher linear resolution.
• 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: Can take a variety of interchangeable lenses, including specialty optics.
• Longer lasting: Can take more shots (500 versus 400) on 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 available for much longer (launched in September 2012).

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: Has a touchscreen to facilitate handling and shooting adjustments.
• 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 an integrated lens, while the A99 requires a separate lens.
• More compact: Is smaller (133x94mm vs 147x111mm) and will fit more readily into a bag.
• Easier travel charging: Can be conveniently charged via its USB port.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• 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.

If the number of relative strengths (bullet points above) is taken as a guide, the RX10 IV emerges as the winner of the match-up (14 : 11 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 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 A99 and the Sony RX10 IV place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Superzoom Camera listings whether the two cameras rank among the cream of the crop.

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the A99 or the RX10 IV. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.

Expert reviews

This is why expert reviews are important. 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 A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
2.		Sony RX10 IV	5/5	+	3.5/5	84/100	4.5/5	5/5	Sep 2017	1,699	amazon.com
3.		Canon R6	5/5	+ +	4/5	90/100	4.5/5	5/5	Jul 2020	2,499	amazon.com
4.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	4,499	amazon.com
5.		Sony RX100 VI	4.5/5	+ +	..	83/100	4/5	4.5/5	Jun 2018	1,199	ebay.com
6.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	3,199	ebay.com
7.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	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 RX10 III	5/5	+	..	84/100	4.5/5	4.5/5	Mar 2016	1,499	ebay.com
10.		Sony RX100 V	4.5/5	+ +	..	83/100	4/5	4.5/5	Oct 2016	999	ebay.com
11.		Sony A7R II	5/5	+ +	5/5	90/100	5/5	5/5	Jun 2015	3,199	ebay.com
12.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
13.		Sony RX10 II	5/5	+ +	..	82/100	4.5/5	4/5	Jun 2015	1,299	ebay.com
14.		Sony RX10	5/5	+	..	80/100	4.5/5	4.5/5	Oct 2013	1,299	ebay.com
15.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
16.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
17.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
Notes: (+ +) 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. Also, please note that some of the review sites have changed their methodology and reporting over time.

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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 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.

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