Canon 20D vs Sony A7S

The Canon EOS 20D and the Sony Alpha A7S are two digital cameras that were revealed to the public, respectively, in August 2004 and April 2014. The 20D is a DSLR, while the A7S is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (20D) and a full frame (A7S) sensor. The Canon has a resolution of 8.2 megapixels, whereas the Sony provides 12 MP.

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

Headline Specifications

Canon 20D		Sony A7S
Digital single lens reflex		Mirrorless system camera
Canon EF mount lenses		Sony E mount lenses
8.2 MP – APS-C sensor		12 MP – Full Frame sensor
no Video		1080/60p Video
ISO 100-1,600 (100 - 3,200)		ISO 100-102,400 (50 - 409,600)
Optical viewfinder		Electronic viewfinder (2400k dots)
1.8" LCD – 118k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Tilting screen (no touchscreen)
5 shutter flaps per second		5 shutter flaps per second
not weather sealed		Weathersealed body
700 shots per battery charge		380 shots per battery charge
144 x 106 x 72 mm, 770 g		127 x 94 x 48 mm, 489 g

Check 20D offers at
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Check A7S offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS 20D and the Sony Alpha A7S? 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 20D and the Sony A7S is provided in the side-by-side display below. 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 A7S is notably smaller (22 percent) than the Canon 20D. Moreover, the A7S is substantially lighter (36 percent) than the 20D. It is noteworthy in this context that the A7S is splash and dust-proof, while the 20D 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. A larger imaging sensor will tend to go along with bigger and heavier lenses, although exceptions exist. You can compare the optics available for the two cameras in the Canon EF Lens Catalog (20D) and the Sony FE Lens Catalog (A7S). Mirrorless cameras, such as the A7S, have moreover the advantage that they can use many lenses from other systems via adapters, as they have a relatively short flange to focal plane distance.

Concerning battery life, the 20D gets 700 shots out of its Canon BP-511A battery, while the A7S can take 380 images on a single charge of its Sony NP-FW50 power pack. The power pack in the A7S can be charged via the USB port, which can be very convenient when travelling.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras 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 20D	144 mm	106 mm	72 mm	770 g	700	n	Aug 2004	1,499	ebay.com
2.		Sony A7S	127 mm	94 mm	48 mm	489 g	380	Y	Apr 2014	2,499	ebay.com
3.		Canon 7D II	149 mm	112 mm	78 mm	910 g	670	Y	Sep 2014	1,799	ebay.com
4.		Canon 60D	145 mm	106 mm	79 mm	755 g	1100	Y	Aug 2010	1,399	ebay.com
5.		Canon 7D	148 mm	111 mm	74 mm	860 g	800	Y	Sep 2009	1,699	ebay.com
6.		Canon 50D	146 mm	108 mm	74 mm	822 g	800	Y	Aug 2008	1,299	ebay.com
7.		Canon 40D	146 mm	108 mm	74 mm	822 g	750	n	Aug 2007	1,299	ebay.com
8.		Canon 30D	144 mm	106 mm	74 mm	785 g	750	n	Feb 2006	1,399	ebay.com
9.		Canon XT	127 mm	94 mm	64 mm	540 g	400	n	Feb 2005	899	ebay.com
10.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	1,999	ebay.com
11.		Canon Rebel	142 mm	99 mm	72 mm	649 g	400	n	Aug 2003	899	ebay.com
12.		Nikon Df	144 mm	110 mm	67 mm	760 g	1400	Y	Nov 2013	2,749	ebay.com
13.		Nikon D200	147 mm	113 mm	74 mm	920 g	400	Y	Nov 2005	1,699	ebay.com
14.		Sony ZV-E1	121 mm	72 mm	54 mm	483 g	570	Y	Mar 2023	2,199	amazon.com
15.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
16.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	1,699	ebay.com
17.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	2,299	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
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Any camera decision will obviously take relative prices into account. 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 20D was launched at a markedly lower price (by 40 percent) than the A7S, 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better isolate a subject from the 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 Canon 20D features an APS-C sensor and the Sony A7S a full frame sensor. The sensor area in the A7S is 153 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 12MP, the A7S offers a higher resolution than the 20D (8.2MP), but the A7S nevertheless has larger individual pixels (pixel pitch of 8.45μm versus 6.42μm for the 20D) due to its larger sensor. Moreover, the A7S is a much more recent model (by 9 years and 7 months) than the 20D, 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 A7S implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7S for good quality output (200 dots per inch) amounts to 21.2 x 14.2 inches or 53.8 x 36 cm, for very good quality (250 dpi) 17 x 11.3 inches or 43.1 x 28.8 cm, and for excellent quality (300 dpi) 14.1 x 9.4 inches or 35.9 x 24 cm. The corresponding values for the Canon 20D are 17.5 x 11.7 inches or 44.5 x 29.7 cm for good quality, 14 x 9.3 inches or 35.6 x 23.7 cm for very good quality, and 11.7 x 7.8 inches or 29.7 x 19.8 cm for excellent quality prints.

The Canon EOS 20D 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 A7S are ISO 100 to ISO 102400, with the possibility to increase the ISO range to 50-409600.

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 A7S offers substantially better image quality than the 20D (overall score 25 points higher). The advantage is based on 2 bits higher color depth, 2.2 EV in additional dynamic range, and 2.4 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 20D	APS-C	8.2	3504	2336	none	21.9	11.0	721	62
2.		Sony A7S	Full Frame	12.0	4240	2832	1080/60p	23.9	13.2	3702	87
3.		Canon 7D II	APS-C	20.0	5472	3648	1080/60p	22.4	11.8	1082	70
4.		Canon 60D	APS-C	17.9	5184	3456	1080/30p	22.2	11.5	813	66
5.		Canon 7D	APS-C	17.9	5184	3456	1080/30p	22.0	11.7	854	66
6.		Canon 50D	APS-C	15.1	4752	3168	none	21.8	11.4	696	63
7.		Canon 40D	APS-C	10.1	3888	2592	none	22.1	11.3	703	64
8.		Canon 30D	APS-C	8.2	3504	2336	none	21.5	10.8	736	59
9.		Canon XT	APS-C	8.0	3456	2304	none	21.8	10.8	637	60
10.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
11.		Canon Rebel	APS-C	6.3	3072	2048	none	21.0	10.8	544	55
12.		Nikon Df	Full Frame	16.2	4928	3280	none	24.6	13.1	3279	89
13.		Nikon D200	APS-C	10.0	3872	2592	none	22.3	11.5	583	64
14.		Sony ZV-E1	Full Frame	12.0	4240	2832	4K/60p	25.4	14.6	3181	96
15.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
16.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90
17.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras are not only capable of taking still images, but can also record movies. The A7S indeed provides for movie recording, while the 20D does not. The highest resolution format that the A7S can use is 1080/60p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A7S has an electronic viewfinder (2400k dots), while the 20D 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 A7S offers a wider field of view (100%) than the one in the 20D (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A7S has a higher magnification (0.71x vs 0.56x), 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 20D and Sony A7S 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 20D	optical	Y	1.8 / 118	fixed	n	1/8000s	5.0/s	Y	n
2.		Sony A7S	2400	n	3.0 / 921	tilting	n	1/8000s	5.0/s	n	n
3.		Canon 7D II	optical	Y	3.0 / 1040	fixed	n	1/8000s	10.0/s	Y	n
4.		Canon 60D	optical	Y	3.0 / 1040	swivel	n	1/8000s	5.3/s	Y	n
5.		Canon 7D	optical	Y	3.0 / 920	fixed	n	1/8000s	8.0/s	Y	n
6.		Canon 50D	optical	Y	3.0 / 920	fixed	n	1/8000s	6.3/s	Y	n
7.		Canon 40D	optical	Y	3.0 / 230	fixed	n	1/8000s	6.5/s	Y	n
8.		Canon 30D	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
9.		Canon XT	optical	n	1.8 / 115	fixed	n	1/4000s	3.0/s	Y	n
10.		Canon 10D	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
11.		Canon Rebel	optical	n	1.8 / 118	fixed	n	1/4000s	2.5/s	Y	n
12.		Nikon Df	optical	Y	3.2 / 921	fixed	n	1/4000s	5.5/s	n	n
13.		Nikon D200	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
14.		Sony ZV-E1	none	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
15.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
16.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
17.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
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 20D has one, while the A7S does not. While the built-in flash of the 20D is not very powerful, it can at times be useful as a fill-in light.

The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the A7S is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).

The 20D writes its imaging data to Compact Flash cards, while the A7S uses SDXC or Memory Stick PRO Duo cards.

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 20D and Sony Alpha A7S 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 20D	Y	- / -	-	-	-	1.1	-	-	-
2.		Sony A7S	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
3.		Canon 7D II	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
4.		Canon 60D	Y	mono / mono	Y	-	mini	2.0	-	-	-
5.		Canon 7D	Y	mono / -	Y	-	mini	2.0	-	-	-
6.		Canon 50D	Y	- / -	-	-	mini	2.0	-	-	-
7.		Canon 40D	Y	- / -	-	-	-	2.0	-	-	-
8.		Canon 30D	Y	- / -	-	-	-	2.0	-	-	-
9.		Canon XT	Y	- / -	-	-	-	2.0	-	-	-
10.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
11.		Canon Rebel	Y	- / -	-	-	-	1.1	-	-	-
12.		Nikon Df	Y	- / -	-	-	mini	2.0	-	-	-
13.		Nikon D200	Y	- / -	-	-	-	2.0	-	-	-
14.		Sony ZV-E1	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
15.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony A7	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-

It is notable that the A7S offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the 20D does not provide wifi capability.

Studio photographers will appreciate that the Canon 20D (unlike the A7S) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 20D and the A7S have been discontinued, but can regularly be found used on ebay. The 20D was replaced by the Canon 30D, while the A7S was followed by the Sony A7S II. Further information on the features and operation of the 20D and A7S can be found, respectively, in the Canon 20D Manual (free pdf) or the online Sony A7S Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Canon 20D or the Sony A7S – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Canon EOS 20D:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Easier setting verification: Features an LCD display on top to control shooting parameters.
• Longer lasting: Can take more shots (700 versus 380) on a single battery charge.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More affordable: Was introduced into a lower priced category (40 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2004).

Arguments in favor of the Sony Alpha A7S:

• More detail: Has more megapixels (12 vs 8.2MP), which boosts linear resolution by 21%.
• Better image quality: Scores substantially higher (25 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.2 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (2.4 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 0.56x).
• Larger screen: Has a bigger rear LCD (3.0" vs 1.8") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 118k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• More compact: Is smaller (127x94mm vs 144x106mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 281g or 36 percent) and is thus easier to take along.
• Easier travel charging: Can be conveniently charged via its USB port.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Faster data transfer: Supports a more advanced USB protocol (2.0 vs 1.1).
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More modern: Reflects 9 years and 7 months of technical progress since the 20D launch.

If the count of individual advantages (bullet points above) is taken as a guide, the A7S is the clear winner of the contest (22 : 7 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. 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 20D and the Sony A7S place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens Camera listings 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 remains incomplete and does no justice, for example, to the way the 20D or the A7S 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 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 20D	..	..	..	+ +	..	..	Aug 2004	1,499	ebay.com
2.		Sony A7S	4/5	..	..	86/100	4.5/5	5/5	Apr 2014	2,499	ebay.com
3.		Canon 7D II	4.5/5	+	3.5/5	84/100	4/5	4.5/5	Sep 2014	1,799	ebay.com
4.		Canon 60D	5/5	+	..	79/100	4/5	4.5/5	Aug 2010	1,399	ebay.com
5.		Canon 7D	5/5	+ +	..	84/100	4.5/5	4.5/5	Sep 2009	1,699	ebay.com
6.		Canon 50D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2008	1,299	ebay.com
7.		Canon 40D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2007	1,299	ebay.com
8.		Canon 30D	..	+ +	..	+ +	o	..	Feb 2006	1,399	ebay.com
9.		Canon XT	..	80/100	..	+ +	o	..	Feb 2005	899	ebay.com
10.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	1,999	ebay.com
11.		Canon Rebel	..	..	..	+ +	..	..	Aug 2003	899	ebay.com
12.		Nikon Df	4/5	..	..	81/100	4/5	4/5	Nov 2013	2,749	ebay.com
13.		Nikon D200	..	+ +	..	+ +	o	..	Nov 2005	1,699	ebay.com
14.		Sony ZV-E1	..	+	4/5	..	..	4.5/5	Mar 2023	2,199	amazon.com
15.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
16.		Sony A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	1,699	ebay.com
17.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	2,299	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The assessments were made in relation to similar cameras of the same technological generation. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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

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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