Canon 5D Mark III vs Sony A900

The Canon EOS 5D Mark III and the Sony Alpha A900 are two professional cameras that were officially introduced, respectively, in March 2012 and September 2008. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with a full frame sensor. The Canon has a resolution of 22.1 megapixels, whereas the Sony 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

Canon 5D Mark III		Sony A900
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Sony A mount lenses
22.1 MP – Full Frame sensor		24.4 MP – Full Frame sensor
1080/30p Video		no Video
ISO 100-25,600 (50 - 102,400)		ISO 200-3,200 (100 - 6,400)
Optical viewfinder		Optical viewfinder
3.2" LCD – 1040k dots		3.0" LCD – 922k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
6 shutter flaps per second		5 shutter flaps per second
Lens stabilization only		In-body stabilization
Weathersealed body		Weathersealed body
950 shots per battery charge		880 shots per battery charge
152 x 116 x 76 mm, 950 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 Canon EOS 5D Mark 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 side-by-side display below illustrates the physical size and weight of the Canon 5D Mark III and the Sony A900. 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 A900 is somewhat larger (4 percent) than the Canon 5D Mark III. However, the A900 is markedly lighter (6 percent) than the 5D Mark 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 5D Mark III gets 950 shots out of its Canon LP-E6 battery, while the A900 can take 880 images on a single charge of its Sony NP-FM500H power pack.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
2.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
3.		Canon 5D Mark IV	151 mm	116 mm	76 mm	890 g	900	Y	Aug 2016	3,499	amazon.com
4.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
5.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
6.		Canon 6D	145 mm	111 mm	71 mm	770 g	1090	Y	Sep 2012	2,099	ebay.com
7.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
8.		Canon 5D	152 mm	113 mm	75 mm	895 g	400	Y	Aug 2005	3,299	ebay.com
9.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
10.		Nikon D600	141 mm	113 mm	82 mm	850 g	900	Y	Sep 2012	2,099	ebay.com
11.		Nikon D800	146 mm	123 mm	82 mm	1000 g	900	Y	Feb 2012	2,999	ebay.com
12.		Nikon D800E	146 mm	123 mm	82 mm	1000 g	900	Y	Feb 2012	3,299	ebay.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

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 A900 was launched at a somewhat lower price (by 14 percent) than the 5D Mark III, which makes it more attractive for photographers on a tight budget. 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the 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. 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.

Despite having a slightly smaller sensor, the A900 offers a higher resolution of 24.4 megapixels, compared with 22.1 MP of the 5D Mark III. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 5.94μm versus 6.25μm for the 5D Mark III). Moreover, it should be noted that the 5D Mark III is much more recent (by 3 years and 5 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 pixels.

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 Canon 5D Mark III are 28.8 x 19.2 inches or 73.2 x 48.8 cm for good quality, 23 x 15.4 inches or 58.5 x 39 cm for very good quality, and 19.2 x 12.8 inches or 48.8 x 32.5 cm for excellent quality prints.

The Canon EOS 5D Mark III has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 50-102400. 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.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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.		Canon 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
2.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
3.		Canon 5D Mark IV	Full Frame	30.1	6720	4480	4K/30p	24.8	13.6	2995	91
4.		Canon 5DS	Full Frame	50.3	8688	5792	1080/30p	24.7	12.4	2381	87
5.		Canon 5DS R	Full Frame	50.3	8688	5792	1080/30p	24.6	12.4	2308	86
6.		Canon 6D	Full Frame	20.0	5472	3648	1080/30p	23.8	12.1	2340	82
7.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
8.		Canon 5D	Full Frame	12.7	4368	2912	none	22.9	11.1	1368	71
9.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
10.		Nikon D600	Full Frame	24.2	6016	4016	1080/30p	25.1	14.2	2980	94
11.		Nikon D800	Full Frame	36.2	7360	4912	1080/30p	25.3	14.4	2853	95
12.		Nikon D800E	Full Frame	36.2	7360	4912	1080/30p	25.6	14.3	2979	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 cannot only take still pictures, but also record videos. The 5D Mark III indeed provides movie recording capabilities, while the A900 does not. The highest resolution format that the 5D Mark III can use is 1080/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The 5D Mark III and the A900 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 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 5D Mark III (0.74x vs 0.71x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Canon 5D Mark III and Sony A900 along with similar information for a selection of comparators.

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.		Canon 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
2.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
3.		Canon 5D Mark IV	optical	Y	3.2 / 1620	fixed	Y	1/8000s	7.0/s	n	n
4.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
5.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
6.		Canon 6D	optical	Y	3.0 / 1040	fixed	n	1/4000s	4.5/s	n	n
7.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
8.		Canon 5D	optical	Y	2.5 / 230	fixed	n	1/8000s	3.0/s	n	n
9.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
10.		Nikon D600	optical	Y	3.0 / 921	fixed	n	1/4000s	5.5/s	Y	n
11.		Nikon D800	optical	Y	3.2 / 921	fixed	n	1/8000s	4.0/s	Y	n
12.		Nikon D800E	optical	Y	3.2 / 921	fixed	n	1/8000s	4.0/s	Y	n
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 5D Mark III is in-body image stabilization (IBIS). The A900 reduces the risk of handshake-induced blur with all attached lenses, while the 5D Mark III offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The 5D Mark III writes its imaging data to Compact Flash 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 Canon EOS 5D Mark 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.		Canon 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
2.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-
3.		Canon 5D Mark IV	Y	mono / mono	Y	Y	mini	3.0	Y	Y	-
4.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
5.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
6.		Canon 6D	Y	mono / mono	Y	-	mini	2.0	Y	-	-
7.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
8.		Canon 5D	Y	- / -	-	-	-	2.0	-	-	-
9.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
10.		Nikon D600	Y	mono / mono	Y	Y	mini	2.0	-	-	-
11.		Nikon D800	Y	mono / mono	Y	Y	mini	3.0	-	-	-
12.		Nikon D800E	Y	mono / mono	Y	Y	mini	3.0	-	-	-
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	-	-	-

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

Both the 5D Mark III and the A900 have been discontinued, but can regularly be found used on ebay. The A900 was replaced by the Sony A99, while the 5D Mark III was followed by the Canon 5D Mark IV. Further information on the features and operation of the 5D Mark III and A900 can be found, respectively, in the Canon 5D Mark III Manual (free pdf) or the online Sony A900 Manual.

Review summary

So what conclusions can be drawn? Is the Canon 5D Mark III better than the Sony A900 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Canon EOS 5D Mark III:

• Better low-light sensitivity: Requires less light for good images (0.7 stops ISO advantage).
• Broader imaging potential: Can record not only still images but also 1080/30p movies.
• 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 (1040k vs 922k dots).
• Faster burst: Shoots at higher frequency (6 vs 5 flaps/sec) to capture the decisive moment.
• More modern: Reflects 3 years and 5 months of technical progress since the A900 launch.

Advantages of the Sony Alpha A900:

• More detail: Has more megapixels (24.4 vs 22.1MP), which boosts linear resolution by 5%.
• More dynamic range: Captures a broader range of light and dark details (0.6 EV of extra DR).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.74x vs 0.71x).
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• More affordable: Was released into a lower priced segment (14 percent cheaper at launch).
• 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 match-up finishes in a tie (6 points each). 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 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 Canon 5D Mark III 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 partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the 5D Mark III or the A900. 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 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.		Canon 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
2.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
3.		Canon 5D Mark IV	4.5/5	+ +	4/5	87/100	4.5/5	4.5/5	Aug 2016	3,499	amazon.com
4.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	3,699	ebay.com
5.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	3,699	ebay.com
6.		Canon 6D	5/5	+ +	..	83/100	4.5/5	4.5/5	Sep 2012	2,099	ebay.com
7.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
8.		Canon 5D	..	88/100	..	+ +	o	..	Aug 2005	3,299	ebay.com
9.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
10.		Nikon D600	4/5	+ +	..	87/100	5/5	4.5/5	Sep 2012	2,099	ebay.com
11.		Nikon D800	5/5	+ +	..	82/100	5/5	5/5	Feb 2012	2,999	ebay.com
12.		Nikon D800E	..	..	..	84/100	5/5	5/5	Feb 2012	3,299	ebay.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.

Care should be taken when interpreting the review scores above, though. The assessments were made in relation to similar cameras of the same technological generation. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

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Check A900 offers at
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Other camera comparisons

Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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