Canon 40D vs Sony A900

The Canon EOS 40D and the Sony Alpha A900 are two digital cameras that were announced, respectively, in August 2007 and September 2008. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (40D) and a full frame (A900) sensor. The Canon has a resolution of 10.1 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 40D		Sony A900
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Sony A mount lenses
10.1 MP – APS-C sensor		24.4 MP – Full Frame sensor
no Video		no Video
ISO 100-1,600 (100 - 3,200)		ISO 200-3,200 (100 - 6,400)
Optical viewfinder		Optical viewfinder
3.0" LCD – 230k dots		3.0" LCD – 922k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
6.5 shutter flaps per second		5 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
750 shots per battery charge		880 shots per battery charge
146 x 108 x 74 mm, 822 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 40D 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 Canon 40D and the Sony A900 are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side 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 notably larger (16 percent) than the Canon 40D. Moreover, the A900 is markedly heavier (9 percent) than the 40D. It is noteworthy in this context that the A900 is splash and dust-proof, while the 40D 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 40D gets 750 shots out of its Canon BP-511A battery, while the A900 can take 880 images on a single charge of its Sony NP-FM500H power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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.		Canon 40D	146 mm	108 mm	74 mm	822 g	750	n	Aug 2007	1,299	ebay.com
2.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
3.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	1,999	ebay.com
4.		Canon 20D	144 mm	106 mm	72 mm	770 g	700	n	Aug 2004	1,499	ebay.com
5.		Canon 30D	144 mm	106 mm	74 mm	785 g	750	n	Feb 2006	1,399	ebay.com
6.		Canon 50D	146 mm	108 mm	74 mm	822 g	800	Y	Aug 2008	1,299	ebay.com
7.		Canon 60D	145 mm	106 mm	79 mm	755 g	1100	Y	Aug 2010	1,399	ebay.com
8.		Canon T3	130 mm	100 mm	78 mm	495 g	700	n	Feb 2011	449	ebay.com
9.		Canon XS	126 mm	98 mm	65 mm	502 g	500	n	Jun 2008	449	ebay.com
10.		Canon XSi	129 mm	98 mm	62 mm	524 g	500	n	Jan 2008	799	ebay.com
11.		Canon XTi	127 mm	84 mm	65 mm	556 g	370	n	Aug 2006	799	ebay.com
12.		Nikon D90	132 mm	103 mm	77 mm	703 g	850	n	Aug 2008	1,299	ebay.com
13.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
14.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
15.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
16.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	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 obviously take relative prices into account. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The 40D 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.

Sensor comparison

The size of the imaging sensor is a crucial determinant of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units 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.

Of the two cameras under consideration, the Canon 40D features an APS-C sensor and the Sony A900 a full frame sensor. The sensor area in the A900 is 160 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.6 and 1.0. 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 40D (10.1MP), but the A900 nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 5.73μm for the 40D) due to its larger sensor. Moreover, the A900 is a somewhat more recent model (by 1 year) than the 40D, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units.

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 40D are 19.4 x 13 inches or 49.4 x 32.9 cm for good quality, 15.6 x 10.4 inches or 39.5 x 26.3 cm for very good quality, and 13 x 8.6 inches or 32.9 x 21.9 cm for excellent quality prints.

The Canon EOS 40D has a native sensitivity range from ISO 100 to ISO 1600, which can be extended to ISO 100-3200. 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"). Of the two cameras under consideration, the A900 offers substantially better image quality than the 40D (overall score 15 points higher). The advantage is based on 1.6 bits higher color depth, 1 EV in additional dynamic range, and 1 stops in additional low light sensitivity. The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar 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 40D	APS-C	10.1	3888	2592	none	22.1	11.3	703	64
2.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
3.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
4.		Canon 20D	APS-C	8.2	3504	2336	none	21.9	11.0	721	62
5.		Canon 30D	APS-C	8.2	3504	2336	none	21.5	10.8	736	59
6.		Canon 50D	APS-C	15.1	4752	3168	none	21.8	11.4	696	63
7.		Canon 60D	APS-C	17.9	5184	3456	1080/30p	22.2	11.5	813	66
8.		Canon T3	APS-C	12.2	4272	2848	720/30p	21.9	11.0	755	62
9.		Canon XS	APS-C	10.1	3888	2592	none	22.0	10.9	719	62
10.		Canon XSi	APS-C	12.2	4272	2848	none	21.9	10.8	692	61
11.		Canon XTi	APS-C	10.1	3888	2592	none	22.1	11.0	664	62
12.		Nikon D90	APS-C	12.2	4288	2848	720/24p	22.7	12.5	977	73
13.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
14.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
15.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
16.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
17.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The 40D 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 viewfinder in the A900 offers a wider field of view (100%) than the one in the 40D (95%), 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 0.59x), 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 Canon 40D, 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.		Canon 40D	optical	Y	3.0 / 230	fixed	n	1/8000s	6.5/s	Y	n
2.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
3.		Canon 10D	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
4.		Canon 20D	optical	Y	1.8 / 118	fixed	n	1/8000s	5.0/s	Y	n
5.		Canon 30D	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
6.		Canon 50D	optical	Y	3.0 / 920	fixed	n	1/8000s	6.3/s	Y	n
7.		Canon 60D	optical	Y	3.0 / 1040	swivel	n	1/8000s	5.3/s	Y	n
8.		Canon T3	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
9.		Canon XS	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
10.		Canon XSi	optical	n	3.0 / 230	fixed	n	1/4000s	3.5/s	Y	n
11.		Canon XTi	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
12.		Nikon D90	optical	Y	3.0 / 920	fixed	n	1/4000s	4.5/s	Y	n
13.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
14.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
15.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
16.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/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 difference between the cameras concerns the presence of an on-board flash. The 40D has one, while the A900 does not. While the built-in flash of the 40D is not very powerful, it can at times be useful as a fill-in light.

The 40D writes its imaging data to Compact Flash 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 40D 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 Canon EOS 40D 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 40D	Y	- / -	-	-	-	2.0	-	-	-
2.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-
3.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
4.		Canon 20D	Y	- / -	-	-	-	1.1	-	-	-
5.		Canon 30D	Y	- / -	-	-	-	2.0	-	-	-
6.		Canon 50D	Y	- / -	-	-	mini	2.0	-	-	-
7.		Canon 60D	Y	mono / mono	Y	-	mini	2.0	-	-	-
8.		Canon T3	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Canon XS	Y	- / -	-	-	-	2.0	-	-	-
10.		Canon XSi	Y	- / -	-	-	mini	2.0	-	-	-
11.		Canon XTi	Y	- / -	-	-	-	2.0	-	-	-
12.		Nikon D90	Y	mono / mono	-	-	mini	2.0	-	-	-
13.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
14.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
15.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
16.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
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 40D and the A900 have been discontinued, but can regularly be found used on ebay. The 40D was replaced by the Canon 50D, while the A900 was followed by the Sony A99. Further information on the features and operation of the 40D and A900 can be found, respectively, in the Canon 40D Manual (free pdf) or the online Sony A900 Manual.

Review summary

So what is the bottom line? Is there a clear favorite between the Canon 40D and the Sony A900? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Canon EOS 40D:

• Faster burst: Shoots at higher frequency (6.5 vs 5 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (146x108mm vs 156x117mm) and thus needs less room in the bag.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (57 percent cheaper at launch).
• More heavily discounted: Has been on the market for longer (launched in August 2007).

Arguments in favor of the Sony Alpha A900:

• More detail: Has more megapixels (24.4 vs 10.1MP), which boosts linear resolution by 56%.
• Better image quality: Scores substantially higher (15 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (1.6 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (1 stops ISO advantage).
• More complete view: Has a viewfinder with a larger field of view (100% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.74x vs 0.59x).
• More detailed LCD: Has a higher resolution rear screen (922k vs 230k dots).
• Longer lasting: Gets more shots (880 versus 750) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More modern: Was introduced somewhat (1 year) more recently.

If the count of individual advantages (bullet points above) is taken as a guide, the A900 is the clear winner of the contest (13 : 5 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 Canon 40D 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 says little about, for example, the shooting experience and imaging performance of the 40D and the A900 in practical situations. 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 where reviews by experts come in. 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.		Canon 40D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2007	1,299	ebay.com
2.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
3.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	1,999	ebay.com
4.		Canon 20D	..	..	..	+ +	..	..	Aug 2004	1,499	ebay.com
5.		Canon 30D	..	+ +	..	+ +	o	..	Feb 2006	1,399	ebay.com
6.		Canon 50D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2008	1,299	ebay.com
7.		Canon 60D	5/5	+	..	79/100	4/5	4.5/5	Aug 2010	1,399	ebay.com
8.		Canon T3	..	80/100	..	69/100	4/5	4.5/5	Feb 2011	449	ebay.com
9.		Canon XS	..	82/100	..	+ +	3.5/5	4.5/5	Jun 2008	449	ebay.com
10.		Canon XSi	..	+ +	..	+ +	4/5	4.5/5	Jan 2008	799	ebay.com
11.		Canon XTi	..	+ +	..	+ +	o	4/5	Aug 2006	799	ebay.com
12.		Nikon D90	..	+ +	..	+ +	4/5	4.5/5	Aug 2008	1,299	ebay.com
13.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
14.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
15.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
16.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	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. 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

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