Sony A77 vs A900

The Sony Alpha SLT-A77 and the Sony Alpha A900 are two digital cameras that were revealed to the public, respectively, in August 2011 and September 2008. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (A77) and a full frame (A900) sensor. The A77 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 A77		Sony A900
Digital single lens reflex		Digital single lens reflex
Sony A mount lenses		Sony A mount lenses
24 MP – APS-C sensor		24.4 MP – Full Frame sensor
1080/60p Video		no Video
ISO 100-16,000 (50 - 25,600)		ISO 200-3,200 (100 - 6,400)
Electronic viewfinder (2359k dots)		Optical viewfinder
3.0" LCD – 921k dots		3.0" LCD – 922k dots
Fully flexible screen (no touchscreen)		Fixed screen (not touch-sensitive)
12 shutter flaps per second		5 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
470 shots per battery charge		880 shots per battery charge
143 x 104 x 81 mm, 732 g		156 x 117 x 82 mm, 895 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha SLT-A77 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

An illustration of the physical size and weight of the Sony A77 and the Sony A900 is provided in the side-by-side display below. 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 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 A900 is notably larger (23 percent) than the Sony A77. Moreover, the A900 is markedly heavier (22 percent) than the A77. 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.

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 A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
2.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
3.		Canon 6D	145 mm	111 mm	71 mm	770 g	1090	Y	Sep 2012	2,099	ebay.com
4.		Panasonic GH5	139 mm	98 mm	87 mm	725 g	410	Y	Jan 2017	1,999	ebay.com
5.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
6.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999	ebay.com
7.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
8.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
9.		Sony A68	143 mm	104 mm	81 mm	610 g	540	n	Nov 2015	699	ebay.com
10.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	1,199	ebay.com
11.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
12.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
13.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	ebay.com
14.		Sony A6500	120 mm	67 mm	53 mm	453 g	350	Y	Oct 2016	1,399	ebay.com
15.		Sony A6600	120 mm	67 mm	69 mm	503 g	810	Y	Aug 2019	1,399	amazon.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 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 A77 was launched at a markedly lower price (by 53 percent) than the A900, which puts it into a different market segment. 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. 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 tend to be more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A77 features an APS-C sensor and the Sony A900 a full frame sensor. The sensor area in the A900 is 135 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

In terms of chip-set technology, the A77 uses a more advanced image processing engine (BIONZ X) 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 A77 (24MP), but the A900 nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 3.91μm for the A77) due to its larger sensor. However, the A77 is a much more recent model (by 2 years and 11 months) than the A900, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units.

The Sony Alpha SLT-A77 has a native sensitivity range from ISO 100 to ISO 16000, which can be extended to ISO 50-25600. 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.

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors. 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 Overall DXO ratings for the two cameras under consideration are close, suggesting that they provide similar imaging performance. 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 Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
2.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
3.		Canon 6D	Full Frame	20.0	5472	3648	1080/30p	23.8	12.1	2340	82
4.		Panasonic GH5	Four Thirds	20.2	5184	3888	4K/60p	23.9	13.0	807	77
5.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
6.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
7.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
8.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
9.		Sony A68	APS-C	24.0	6000	4000	1080/60i	24.1	13.5	701	79
10.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
11.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
12.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
13.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
14.		Sony A6500	APS-C	24.0	6000	4000	4K/30p	24.5	13.7	1405	85
15.		Sony A6600	APS-C	24.0	6000	4000	4K/30p	23.8	13.4	1497	82

Many modern cameras cannot only take still pictures, but also record videos. The A77 indeed provides movie recording capabilities, while the A900 does not. The highest resolution format that the A77 can use is 1080/60p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A77 has an electronic viewfinder (2359k 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 A900 has a higher magnification than the one of the A77 (0.74x vs 0.73x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The following table reports on some other key feature differences and similarities of the Sony A77, the Sony A900, 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 A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
2.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
3.		Canon 6D	optical	Y	3.0 / 1040	fixed	n	1/4000s	4.5/s	n	n
4.		Panasonic GH5	3680	n	3.2 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
5.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
6.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
7.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
8.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
9.		Sony A68	1440	Y	2.7 / 460	tilting	n	1/4000s	8.0/s	Y	Y
10.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	Y	Y
11.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
12.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
13.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
14.		Sony A6500	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	Y	Y
15.		Sony A6600	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	n	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 A77 has one, while the A900 does not. While the built-in flash of the A77 is not very powerful, it can at times be useful as a fill-in light.

The A77 writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the A900 uses Compact Flash or Memory Stick PRO Duo cards. The A900 features dual card slots, which can be very useful in case a memory card fails. In contrast, the A77 only has one slot.

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-A77 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 A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
2.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-
3.		Canon 6D	Y	mono / mono	Y	-	mini	2.0	Y	-	-
4.		Panasonic GH5	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
5.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
6.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
7.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
8.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
9.		Sony A68	Y	stereo / mono	Y	-	micro	2.0	-	-	-
10.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
11.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
12.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
13.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-
14.		Sony A6500	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
15.		Sony A6600	Y	stereo / mono	Y	Y	YES	2.0	Y	Y	Y

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

Travel and landscape photographers will find it useful that the A77 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

Both the A77 and the A900 have been discontinued, but can regularly be found used on ebay. The A900 was replaced by the Sony A99, while the A77 was followed by the Sony A77 II. Further information on the features and operation of the A77 and A900 can be found, respectively, in the Sony A77 Manual (free pdf) or the online Sony A900 Manual.

Review summary

So how do things add up? Is the Sony A77 better than the Sony A900 or vice versa? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Sony Alpha SLT-A77:

• More dynamic range: Captures a larger spectrum of light and dark details (0.9 EV of extra DR).
• Better jpgs: Has a more modern image processing engine (BIONZ X vs BIONZ).
• Broader imaging potential: Can record not only still images but also 1080/60p movies.
• More framing info: Has an electronic viewfinder that displays shooting data.
• 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 burst: Shoots at higher frequency (12 vs 5 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (143x104mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 163g or 18 percent) and hence easier to carry around.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• More affordable: Was introduced into a lower priced category (53 percent cheaper at launch).
• More modern: Reflects 2 years and 11 months of technical progress since the A900 launch.

Arguments in favor of the Sony Alpha A900:

• Better low-light sensitivity: Can shoot in dim conditions (0.8 stops ISO advantage).
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.74x vs 0.73x).
• Longer lasting: Gets more shots (880 versus 470) out of a single battery charge.
• 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 2008).

If the count of relative strengths (bullet points above) is taken as a measure, the A77 is the clear winner of the match-up (13 : 6 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 A77 and the Sony A900 place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing 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 A77 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 A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
2.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
3.		Canon 6D	5/5	+ +	..	83/100	4.5/5	4.5/5	Sep 2012	2,099	ebay.com
4.		Panasonic GH5	4.5/5	+ +	..	85/100	4.5/5	5/5	Jan 2017	1,999	ebay.com
5.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
6.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	1,999	ebay.com
7.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
8.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
9.		Sony A68	3/5	..	..	..	4/5	4/5	Nov 2015	699	ebay.com
10.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	1,199	ebay.com
11.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
12.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
13.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
14.		Sony A6500	5/5	+ +	3.5/5	85/100	4.5/5	4.5/5	Oct 2016	1,399	ebay.com
15.		Sony A6600	4/5	+	4/5	83/100	4.5/5	4/5	Aug 2019	1,399	amazon.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring 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 comparing ratings of very distinct cameras or ones that are far apart in terms of their release date 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

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