Sony A900 vs Nikon D90

The Sony Alpha A900 and the Nikon D90 are two digital cameras that were announced, respectively, in September 2008 and August 2008. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a full frame (A900) and an APS-C (D90) sensor. The Sony has a resolution of 24.4 megapixels, whereas the Nikon provides 12.2 MP.

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

Headline Specifications

Sony A900		Nikon D90
Digital single lens reflex		Digital single lens reflex
Sony A mount lenses		Nikon F mount lenses
24.4 MP – Full Frame sensor		12.2 MP – APS-C sensor
no Video		720/24p Video
ISO 200-3,200 (100 - 6,400)		ISO 200-3,200 (200 - 6,400)
Optical viewfinder		Optical viewfinder
3.0" LCD – 922k dots		3.0" LCD – 920k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
5 shutter flaps per second		4.5 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		not weather sealed
880 shots per battery charge		850 shots per battery charge
156 x 117 x 82 mm, 895 g		132 x 103 x 77 mm, 703 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A900 and the Nikon D90? 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 A900 and the Nikon D90 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 Nikon D90 is notably smaller (26 percent) than the Sony A900. Moreover, the D90 is markedly lighter (21 percent) than the A900. It is worth mentioning in this context that the A900 is splash and dust resistant, while the D90 does not feature any corresponding weather-sealing.

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 A900 gets 880 shots out of its Sony NP-FM500H battery, while the D90 can take 850 images on a single charge of its Nikon EN-EL3e power pack.

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 A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
2.		Nikon D90	132 mm	103 mm	77 mm	703 g	850	n	Aug 2008	1,299	ebay.com
3.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
4.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
5.		Canon 40D	146 mm	108 mm	74 mm	822 g	750	n	Aug 2007	1,299	ebay.com
6.		Nikon D7000	132 mm	105 mm	77 mm	780 g	1050	Y	Sep 2010	1,499	ebay.com
7.		Nikon D300S	147 mm	115 mm	81 mm	938 g	950	Y	Jul 2009	1,799	ebay.com
8.		Nikon D5000	127 mm	104 mm	80 mm	590 g	510	n	Apr 2009	749	ebay.com
9.		Nikon D700	147 mm	123 mm	77 mm	1074 g	1000	Y	Jul 2008	2,999	ebay.com
10.		Nikon D80	132 mm	103 mm	77 mm	668 g	600	n	Aug 2006	999	ebay.com
11.		Panasonic S1	149 mm	110 mm	97 mm	1017 g	400	Y	Feb 2019	2,499	amazon.com
12.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	1,999	amazon.com
13.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
14.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
15.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
16.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
17.		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 naturally be influenced heavily by the price. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The D90 was launched at a markedly lower price (by 57 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 sensor inside a digital camera is one of the key determinants 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.

Of the two cameras under consideration, the Sony A900 features a full frame sensor and the Nikon D90 an APS-C sensor. The sensor area in the D90 is 57 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 24.4MP, the A900 offers a higher resolution than the D90 (12.2MP), but the A900 nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 5.53μm for the D90) due to its larger sensor. It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation.

The resolution advantage of the Sony A900 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A900 for good quality output (200 dots per inch) amounts to 30.2 x 20.2 inches or 76.8 x 51.2 cm, for very good quality (250 dpi) 24.2 x 16.1 inches or 61.4 x 41 cm, and for excellent quality (300 dpi) 20.2 x 13.4 inches or 51.2 x 34.1 cm. The corresponding values for the Nikon D90 are 21.4 x 14.2 inches or 54.5 x 36.2 cm for good quality, 17.2 x 11.4 inches or 43.6 x 28.9 cm for very good quality, and 14.3 x 9.5 inches or 36.3 x 24.1 cm for excellent quality prints.

The Sony Alpha A900 has a native sensitivity range from ISO 200 to ISO 3200, which can be extended to ISO 100-6400. The corresponding ISO settings for the Nikon D90 are ISO 200 to ISO 3200, with the possibility to increase the ISO range to 200-6400.

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.

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"). Of the two cameras under review, the A900 has a notably higher overall DXO score than the D90 (overall score 6 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 1 bits higher color depth, 0.2 EV of lower dynamic range, and 0.6 stops in additional low light sensitivity. 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 A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
2.		Nikon D90	APS-C	12.2	4288	2848	720/24p	22.7	12.5	977	73
3.		Canon 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
4.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
5.		Canon 40D	APS-C	10.1	3888	2592	none	22.1	11.3	703	64
6.		Nikon D7000	APS-C	16.1	4928	3264	1080/24p	23.5	13.9	1167	80
7.		Nikon D300S	APS-C	12.2	4288	2848	720/24p	22.5	12.2	787	70
8.		Nikon D5000	APS-C	12.2	4288	2848	720/24p	22.7	12.5	868	72
9.		Nikon D700	Full Frame	12.1	4256	2832	none	23.5	12.2	2303	80
10.		Nikon D80	APS-C	10.0	3872	2592	none	22.1	11.2	524	61
11.		Panasonic S1	Full Frame	24.0	6000	4000	4K/60p	25.2	14.5	3333	95
12.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
13.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
14.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
15.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
16.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
17.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79

Many modern cameras are not only capable of taking still images, but can also record movies. The D90 indeed provides for movie recording, while the A900 does not. The highest resolution format that the D90 can use is 720/24p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The A900 and the D90 are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The viewfinder in the A900 offers a wider field of view (100%) than the one in the D90 (96%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A900 has a higher magnification (0.74x vs 0.63x), 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 A900, the Nikon D90, 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 A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
2.		Nikon D90	optical	Y	3.0 / 920	fixed	n	1/4000s	4.5/s	Y	n
3.		Canon 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
4.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
5.		Canon 40D	optical	Y	3.0 / 230	fixed	n	1/8000s	6.5/s	Y	n
6.		Nikon D7000	optical	Y	3.0 / 921	fixed	n	1/8000s	6.0/s	Y	n
7.		Nikon D300S	optical	Y	3.0 / 920	fixed	n	1/8000s	7.0/s	Y	n
8.		Nikon D5000	optical	n	2.7 / 230	full-flex	n	1/4000s	4.0/s	Y	n
9.		Nikon D700	optical	Y	3.0 / 922	fixed	n	1/8000s	8.0/s	Y	n
10.		Nikon D80	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
11.		Panasonic S1	5760	Y	3.2 / 2100	full-flex	Y	1/8000s	9.0/s	n	Y
12.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
13.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
14.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
15.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
16.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
17.		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 feature that differentiates the A900 and the D90 is in-body image stabilization (IBIS). The A900 reduces the risk of handshake-induced blur with all attached lenses, while the D90 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The A900 writes its imaging data to Compact Flash or Memory Stick PRO Duo cards, while the D90 uses SDHC cards. The A900 features dual card slots, which can be very useful in case a memory card fails. In contrast, the D90 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 A900 and Nikon D90 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 A900	Y	- / -	-	-	mini	2.0	-	-	-
2.		Nikon D90	Y	mono / mono	-	-	mini	2.0	-	-	-
3.		Canon 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
4.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
5.		Canon 40D	Y	- / -	-	-	-	2.0	-	-	-
6.		Nikon D7000	Y	mono / mono	Y	-	mini	2.0	-	-	-
7.		Nikon D300S	Y	stereo / mono	Y	-	mini	2.0	-	-	-
8.		Nikon D5000	Y	mono / mono	-	-	mini	2.0	-	-	-
9.		Nikon D700	Y	- / -	-	-	mini	2.0	-	-	-
10.		Nikon D80	Y	- / -	-	-	-	2.0	-	-	-
11.		Panasonic S1	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
12.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
13.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
14.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
15.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
17.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-

Studio photographers will appreciate that the Sony A900 (unlike the D90) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the A900 and the D90 have been discontinued, but can regularly be found used on ebay. The D90 was replaced by the Nikon D7000, while the A900 was followed by the Sony A99. Further information on the features and operation of the A900 and D90 can be found, respectively, in the Sony A900 Manual (free pdf) or the online Nikon D90 Manual.

Review summary

So what conclusions can be drawn? Which of the two cameras – the Sony A900 or the Nikon D90 – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Sony Alpha A900:

• More detail: Offers more megapixels (24.4 vs 12.2MP) with a 41% higher linear resolution.
• Better image quality: Scores markedly higher (6 points) in the DXO overall assessment.
• Better low-light sensitivity: Requires less light for good images (0.6 stops ISO advantage).
• More complete view: Has a viewfinder with a larger field of view (100% vs 96%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.74x vs 0.63x).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• 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.

Arguments in favor of the Nikon D90:

• Broader imaging potential: Can capture not only stills but also 720/24p video.
• More compact: Is smaller (132x103mm vs 156x117mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 192g or 21 percent) and is thus easier to take along.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• More affordable: Was introduced into a lower priced category (57 percent cheaper at launch).

If the count of individual advantages (bullet points above) is taken as a guide, the A900 is the clear winner of the match-up (10 : 5 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision on a new camera. A professional wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports 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 A900 and the Nikon D90 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 comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the A900 and the D90 in practical situations. 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 where reviews by experts come in. 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 A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
2.		Nikon D90	..	+ +	..	+ +	4/5	4.5/5	Aug 2008	1,299	ebay.com
3.		Canon 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
4.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
5.		Canon 40D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2007	1,299	ebay.com
6.		Nikon D7000	4/5	..	..	80/100	4.5/5	4.5/5	Sep 2010	1,499	ebay.com
7.		Nikon D300S	5/5	+ +	..	82/100	4/5	4.5/5	Jul 2009	1,799	ebay.com
8.		Nikon D5000	..	+ +	..	75/100	4/5	4.5/5	Apr 2009	749	ebay.com
9.		Nikon D700	..	89/100	..	+ +	4.5/5	4.5/5	Jul 2008	2,999	ebay.com
10.		Nikon D80	..	+	..	+ +	o	4.5/5	Aug 2006	999	ebay.com
11.		Panasonic S1	4.5/5	+ +	4.5/5	88/100	4.5/5	4/5	Feb 2019	2,499	amazon.com
12.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	1,999	amazon.com
13.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
14.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
15.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
16.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
17.		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 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? 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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