Sony A9 III vs A900

The Sony Alpha A9 III and the Sony Alpha A900 are two professional cameras that were announced, respectively, in November 2023 and September 2008. The A9 III is a mirrorless interchangeable lens camera, while the A900 is a DSLR. Both cameras are equipped with a full frame sensor. The A9 III has a resolution of 24 megapixels, whereas the A900 provides 24.4 MP.

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

Headline Specifications

Sony A9 III		Sony A900
Mirrorless system camera		Digital single lens reflex
Sony E mount lenses		Sony A mount lenses
24 MP – Full Frame sensor		24.4 MP – Full Frame sensor
4K/120p Video		no Video
ISO 250-25,600 (125 - 51,200)		ISO 200-3,200 (100 - 6,400)
Electronic viewfinder (9440k dots)		Optical viewfinder
3.2" LCD – 2100k dots		3.0" LCD – 922k dots
Fully flexible touchscreen		Fixed screen (not touch-sensitive)
120 shutter flaps per second		5 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
530 shots per battery charge		880 shots per battery charge
136 x 97 x 83 mm, 702 g		156 x 117 x 82 mm, 895 g

Check A9 III price at
amazon.com
Check A900 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A9 III and the Sony Alpha A900? 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 physical size and weight of the Sony A9 III and the Sony A900 are illustrated 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 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 A900 is notably larger (38 percent) than the Sony A9 III. Moreover, the A900 is markedly heavier (27 percent) than the A9 III. 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 since they do not consider the interchangeable lenses that both of these cameras require. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

Concerning battery life, the A9 III gets 530 shots out of its Sony NP-FZ100 battery, while the A900 can take 880 images on a single charge of its Sony NP-FM500H power pack. The power pack in the A9 III can be charged via the USB port, so that it is not always necessary to take the battery charger along 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 A9 III	136 mm	97 mm	83 mm	702 g	530	Y	Nov 2023	5,999	amazon.com
2.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
3.		Canon R6 Mark II	138 mm	98 mm	88 mm	670 g	450	Y	Nov 2022	2,499	amazon.com
4.		Panasonic S5 II	134 mm	102 mm	90 mm	740 g	370	Y	Jan 2023	1,999	amazon.com
5.		Sony A1	129 mm	97 mm	81 mm	737 g	530	Y	Jan 2021	6,499	amazon.com
6.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999	ebay.com
7.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	1,999	amazon.com
8.		Sony A7 IV	131 mm	96 mm	80 mm	659 g	580	Y	Oct 2021	2,499	amazon.com
9.		Sony A7C	124 mm	71 mm	60 mm	509 g	740	Y	Sep 2020	1,799	amazon.com
10.		Sony A7R V	131 mm	97 mm	82 mm	723 g	530	Y	Oct 2022	3,899	amazon.com
11.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
12.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
13.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	4,499	amazon.com
14.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
15.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
16.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	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 obviously take relative prices into account. 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 A900 was launched at a markedly lower price (by 50 percent) than the A9 III, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 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. 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 tend to lead to bigger and heavier cameras and lenses.

Both cameras under consideration feature a full frame sensor, but their sensors differ slightly in size. The sensor area in the A900 is 2 percent bigger. They nevertheless have the same format factor of 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

In terms of chip-set technology, the A9 III uses a more advanced image processing engine (Dual BIONZ XR) than the A900 (BIONZ), with benefits for noise reduction, color accuracy, and processing speed.

With 24.4MP, the A900 offers a higher resolution than the A9 III (24MP), but the A900 nevertheless has the same individual pixel size (pixel pitch of 5.94μm) as the A9 III due to its larger sensor. Moreover, the A9 III is a much more recent model (by 15 years and 2 months) than the A900, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units.

The A9 III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Sony Alpha A9 III has a native sensitivity range from ISO 250 to ISO 25600, which can be extended to ISO 125-51200. The corresponding ISO settings for the Sony Alpha A900 are ISO 200 to ISO 3200, with the possibility to increase the ISO range to 100-6400.

In terms of underlying technology, the A9 III is build around a Stacked CMOS sensor, while the A900 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.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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 A9 III	Full Frame	24.0	6000	4000	4K/120p	25.4	14.7	3243	96
2.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
3.		Canon R6 Mark II	Full Frame	24.0	6000	4000	4k/60p	25.4	14.6	3154	96
4.		Panasonic S5 II	Full Frame	24.0	6000	4000	6K/30p	25.4	14.6	3158	96
5.		Sony A1	Full Frame	49.8	8640	5760	8k/30p	25.9	14.5	3163	98
6.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
7.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
8.		Sony A7 IV	Full Frame	32.7	7008	4672	4K/60p	25.4	14.7	3379	97
9.		Sony A7C	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3407	95
10.		Sony A7R V	Full Frame	60.2	9504	6336	8k/24p	26.5	14.8	3187	100
11.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
12.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
13.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
14.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
15.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
16.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
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. The A9 III indeed provides movie recording capabilities, while the A900 does not. The highest resolution format that the A9 III can use is 4K/120p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A9 III has an electronic viewfinder (9440k dots), while the A900 has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the A9 III has a higher magnification than the one of the A900 (0.9x vs 0.74x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Sony A9 III and Sony A900 in connection with corresponding information for a sample of similar 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 A9 III	9440	n	3.2 / 2100	full-flex	Y	1/80000s	120.0/s	n	Y
2.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
3.		Canon R6 Mark II	3690	n	3.0 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
4.		Panasonic S5 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	9.0/s	n	Y
5.		Sony A1	9437	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
6.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
7.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
8.		Sony A7 IV	3686	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
9.		Sony A7C	2360	n	3.0 / 922	swivel	Y	1/4000s	10.0/s	n	Y
10.		Sony A7R V	9440	n	3.2 / 2100	full-flex	Y	1/8000s	10.0/s	n	Y
11.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
12.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
13.		Sony A9 II	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
14.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
15.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
16.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
Note: *) 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 A9 III has a touchscreen, while the A900 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 A9 III 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).

The Sony A9 III has an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.

The A9 III writes its imaging data to CFexpress (type A) or SDXC cards, while the A900 uses Compact Flash or Memory Stick PRO Duo cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails.

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 A9 III and Sony Alpha A900 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 A9 III	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
2.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-
3.		Canon R6 Mark II	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
4.		Panasonic S5 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
5.		Sony A1	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
6.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
7.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
8.		Sony A7 IV	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
9.		Sony A7C	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
10.		Sony A7R V	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
11.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
12.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
13.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
14.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
15.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
16.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-

It is notable that the A9 III offers wifi support, while the A900 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.

The A9 III is a recent model that features in the current product line-up of Sony. In contrast, the A900 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the A900 was succeeded by the Sony A99. Further information on the features and operation of the A9 III and A900 can be found, respectively, in the Sony A9 III Manual (free pdf) or the online Sony A900 Manual.

Review summary

So what is the bottom line? Is there a clear favorite between the Sony A9 III and the Sony A900? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Sony Alpha A9 III:

• Better jpgs: Has a more modern image processing engine (Dual BIONZ XR vs BIONZ).
• Broader imaging potential: Can record not only still images but also 4K/120p movies.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• More framing info: Has an electronic viewfinder that displays shooting data.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.9x vs 0.74x).
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (2100k vs 922k dots).
• More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster shutter: Has higher mechanical shutter speed (1/80000s vs 1/8000s) to freeze action.
• Faster burst: Shoots at higher frequency (120 vs 5 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (136x97mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 193g or 22 percent) and hence easier to carry around.
• Easier travel charging: Can be conveniently charged via its USB port.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• More modern: Reflects 15 years and 2 months of technical progress since the A900 launch.

Reasons to prefer the Sony Alpha A900:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Longer lasting: Gets more shots (880 versus 530) out of a single battery charge.
• More affordable: Was introduced into a lower priced category (50 percent cheaper at launch).
• More heavily discounted: Has been around for much longer (launched in September 2008).

If the number of relative strengths (bullet points above) is taken as a guide, the A9 III is the clear winner of the match-up (22 : 5 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 A9 III and the Sony A900 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens 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 remains incomplete and does no justice, for example, to the way the A9 III or the A900 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.

Expert reviews

This is why hands-on reviews by experts are important. The table below provides a synthesis of the camera assessments of some of the best known photo-gear 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 A9 III	4.5/5	..	..	..	..	..	Nov 2023	5,999	amazon.com
2.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
3.		Canon R6 Mark II	5/5	+ +	4.5/5	91/100	4.5/5	5/5	Nov 2022	2,499	amazon.com
4.		Panasonic S5 II	4.5/5	+ +	5/5	90/100	4.5/5	5/5	Jan 2023	1,999	amazon.com
5.		Sony A1	5/5	o	4.5/5	93/100	4.5/5	5/5	Jan 2021	6,499	amazon.com
6.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	1,999	ebay.com
7.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	1,999	amazon.com
8.		Sony A7 IV	5/5	+ +	4.5/5	89/100	4.5/5	4.5/5	Oct 2021	2,499	amazon.com
9.		Sony A7C	3.5/5	..	3.5/5	86/100	4/5	4/5	Sep 2020	1,799	amazon.com
10.		Sony A7R V	5/5	+ +	4.5/5	92/100	..	..	Oct 2022	3,899	amazon.com
11.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
12.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
13.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	4,499	amazon.com
14.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
15.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
16.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. 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. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

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Other camera comparisons

Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes 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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