Canon 40D vs Sony A99

The Canon EOS 40D and the Sony Alpha SLT-A99 are two digital cameras that were announced, respectively, in August 2007 and September 2012. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (40D) and a full frame (A99) sensor. The Canon has a resolution of 10.1 megapixels, whereas the Sony provides 24 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 A99
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Sony A mount lenses
10.1 MP – APS-C sensor		24 MP – Full Frame sensor
no Video		1080/60p Video
ISO 100-1,600 (100 - 3,200)		ISO 100-25,600
Optical viewfinder		Electronic viewfinder (2359k dots)
3.0" LCD – 230k dots		3.0" LCD – 1229k dots
Fixed screen (not touch-sensitive)		Fully flexible screen (no touchscreen)
6.5 shutter flaps per second		6 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
750 shots per battery charge		500 shots per battery charge
146 x 108 x 74 mm, 822 g		147 x 111 x 78 mm, 812 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 SLT-A99? 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 Canon 40D and the Sony A99 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 size 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 A99 is somewhat larger (3 percent) than the Canon 40D. However, the A99 is slightly lighter (1 percent) than the 40D. It is noteworthy in this context that the A99 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 A99 can take 500 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. 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 A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
3.		Canon T3	130 mm	100 mm	78 mm	495 g	700	n	Feb 2011	449	ebay.com
4.		Canon 60D	145 mm	106 mm	79 mm	755 g	1100	Y	Aug 2010	1,399	ebay.com
5.		Canon 50D	146 mm	108 mm	74 mm	822 g	800	Y	Aug 2008	1,299	ebay.com
6.		Canon XS	126 mm	98 mm	65 mm	502 g	500	n	Jun 2008	449	ebay.com
7.		Canon XSi	129 mm	98 mm	62 mm	524 g	500	n	Jan 2008	799	ebay.com
8.		Canon 30D	144 mm	106 mm	74 mm	785 g	750	n	Feb 2006	1,399	ebay.com
9.		Canon XTi	127 mm	84 mm	65 mm	556 g	370	n	Aug 2006	799	ebay.com
10.		Canon 20D	144 mm	106 mm	72 mm	770 g	700	n	Aug 2004	1,499	ebay.com
11.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	1,999	ebay.com
12.		Nikon D90	132 mm	103 mm	77 mm	703 g	850	n	Aug 2008	1,299	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 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
15.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
16.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	ebay.com
17.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The 40D was launched at a markedly lower price (by 54 percent) than the A99, 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 Canon 40D features an APS-C sensor and the Sony A99 a full frame sensor. The sensor area in the A99 is 157 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 24MP, the A99 offers a higher resolution than the 40D (10.1MP), but the A99 nevertheless has larger individual pixels (pixel pitch of 5.96μm versus 5.73μm for the 40D) due to its larger sensor. Moreover, the A99 is a much more recent model (by 5 years) than the 40D, and its sensor will 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 A99 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A99 for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 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 SLT-A99 are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-25600.

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 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 consideration, the A99 offers substantially better image quality than the 40D (overall score 25 points higher). The advantage is based on 2.9 bits higher color depth, 2.7 EV in additional dynamic range, and 1.1 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.		Canon 40D	APS-C	10.1	3888	2592	none	22.1	11.3	703	64
2.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
3.		Canon T3	APS-C	12.2	4272	2848	720/30p	21.9	11.0	755	62
4.		Canon 60D	APS-C	17.9	5184	3456	1080/30p	22.2	11.5	813	66
5.		Canon 50D	APS-C	15.1	4752	3168	none	21.8	11.4	696	63
6.		Canon XS	APS-C	10.1	3888	2592	none	22.0	10.9	719	62
7.		Canon XSi	APS-C	12.2	4272	2848	none	21.9	10.8	692	61
8.		Canon 30D	APS-C	8.2	3504	2336	none	21.5	10.8	736	59
9.		Canon XTi	APS-C	10.1	3888	2592	none	22.1	11.0	664	62
10.		Canon 20D	APS-C	8.2	3504	2336	none	21.9	11.0	721	62
11.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
12.		Nikon D90	APS-C	12.2	4288	2848	720/24p	22.7	12.5	977	73
13.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
14.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
15.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
16.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
17.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79

Many modern cameras are not only capable of taking still images, but can also record movies. The A99 indeed provides for movie recording, while the 40D does not. The highest resolution format that the A99 can use is 1080/60p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A99 has an electronic viewfinder (2359k dots), while the 40D 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 viewfinder in the A99 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 A99 has a higher magnification (0.71x vs 0.59x), 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 40D and Sony A99 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 40D	optical	Y	3.0 / 230	fixed	n	1/8000s	6.5/s	Y	n
2.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
3.		Canon T3	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
4.		Canon 60D	optical	Y	3.0 / 1040	swivel	n	1/8000s	5.3/s	Y	n
5.		Canon 50D	optical	Y	3.0 / 920	fixed	n	1/8000s	6.3/s	Y	n
6.		Canon XS	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
7.		Canon XSi	optical	n	3.0 / 230	fixed	n	1/4000s	3.5/s	Y	n
8.		Canon 30D	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
9.		Canon XTi	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
10.		Canon 20D	optical	Y	1.8 / 118	fixed	n	1/8000s	5.0/s	Y	n
11.		Canon 10D	optical	Y	1.8 / 118	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 A9 II	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 A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
16.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
17.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/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 A99 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 A99 uses SDXC or Memory Stick PRO Duo cards. The A99 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 SLT-A99 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 A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
3.		Canon T3	Y	stereo / mono	-	-	mini	2.0	-	-	-
4.		Canon 60D	Y	mono / mono	Y	-	mini	2.0	-	-	-
5.		Canon 50D	Y	- / -	-	-	mini	2.0	-	-	-
6.		Canon XS	Y	- / -	-	-	-	2.0	-	-	-
7.		Canon XSi	Y	- / -	-	-	mini	2.0	-	-	-
8.		Canon 30D	Y	- / -	-	-	-	2.0	-	-	-
9.		Canon XTi	Y	- / -	-	-	-	2.0	-	-	-
10.		Canon 20D	Y	- / -	-	-	-	1.1	-	-	-
11.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
12.		Nikon D90	Y	mono / mono	-	-	mini	2.0	-	-	-
13.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
14.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
15.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-
17.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-

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 A99 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

Both the 40D and the A99 have been discontinued, but can regularly be found used on ebay. The 40D was replaced by the Canon 50D, while the A99 was followed by the Sony A99. Further information on the features and operation of the 40D and A99 can be found, respectively, in the Canon 40D Manual (free pdf) or the online Sony A99 Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Canon 40D and the Sony A99? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Canon EOS 40D:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Longer lasting: Can take more shots (750 versus 500) on a single battery charge.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (54 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2007).

Arguments in favor of the Sony Alpha SLT-A99:

• More detail: Has more megapixels (24 vs 10.1MP), which boosts linear resolution by 54%.
• Better image quality: Scores substantially higher (25 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.9 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.7 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (1.1 stops ISO advantage).
• Broader imaging potential: Can capture not only stills but also 1080/60p video.
• More framing info: Has an electronic viewfinder that displays shooting data.
• 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 (0.71x vs 0.59x).
• More detailed LCD: Has a higher resolution rear screen (1229k vs 230k dots).
• 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.
• 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.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More modern: Reflects 5 years of technical progress since the 40D launch.

If the count of relative strengths (bullet points above) is taken as a measure, the A99 is the clear winner of the contest (17 : 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 Canon 40D and the Sony A99 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 the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the 40D or the A99. 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.		Canon 40D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2007	1,299	ebay.com
2.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
3.		Canon T3	..	80/100	..	69/100	4/5	4.5/5	Feb 2011	449	ebay.com
4.		Canon 60D	5/5	+	..	79/100	4/5	4.5/5	Aug 2010	1,399	ebay.com
5.		Canon 50D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2008	1,299	ebay.com
6.		Canon XS	..	82/100	..	+ +	3.5/5	4.5/5	Jun 2008	449	ebay.com
7.		Canon XSi	..	+ +	..	+ +	4/5	4.5/5	Jan 2008	799	ebay.com
8.		Canon 30D	..	+ +	..	+ +	o	..	Feb 2006	1,399	ebay.com
9.		Canon XTi	..	+ +	..	+ +	o	4/5	Aug 2006	799	ebay.com
10.		Canon 20D	..	..	..	+ +	..	..	Aug 2004	1,499	ebay.com
11.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	1,999	ebay.com
12.		Nikon D90	..	+ +	..	+ +	4/5	4.5/5	Aug 2008	1,299	ebay.com
13.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	4,499	amazon.com
14.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
15.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
16.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
17.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

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Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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