Canon SL3 vs Sony A7 III

The Canon EOS Rebel SL3 (called Canon 250D in some regions) and the Sony Alpha A7 III are two digital cameras that were announced, respectively, in April 2019 and February 2018. The SL3 is a DSLR, while the A7 III is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (SL3) and a full frame (A7 III) sensor. Both cameras offer a resolution of 24 megapixels.

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

Headline Specifications

Canon SL3		Sony A7 III
Digital single lens reflex		Mirrorless system camera
Canon EF mount lenses		Sony E mount lenses
24 MP – APS-C sensor		24 MP – Full Frame sensor
4K/25p Video		4K/30p Video
ISO 100-25,600 (100 - 51,200)		ISO 100-51,200 (50 - 204,800)
Optical viewfinder		Electronic viewfinder (2359k dots)
3.0" LCD – 1040k dots		3.0" LCD – 922k dots
Swivel touchscreen		Tilting touchscreen
5 shutter flaps per second		10 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
1070 shots per battery charge		610 shots per battery charge
122 x 93 x 70 mm, 449 g		127 x 96 x 74 mm, 650 g

Check SL3 price at
amazon.com
Check A7 III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS Rebel SL3 and the Sony Alpha A7 III? 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 SL3 and the Sony A7 III 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.

The SL3 can be obtained in two different colors (black, white), while the A7 III is only available in black.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7 III is notably larger (7 percent) than the Canon SL3. Moreover, the A7 III is substantially heavier (45 percent) than the SL3. It is noteworthy in this context that the A7 III is splash and dust-proof, while the SL3 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 (SL3) and the Sony FE Lens Catalog (A7 III). Mirrorless cameras, such as the A7 III, 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 SL3 gets 1070 shots out of its Canon LP-E17 battery, while the A7 III can take 610 images on a single charge of its Sony NP-FZ100 power pack. The power pack in the A7 III can be charged via the USB port, which can be very convenient when travelling.

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 SL3	122 mm	93 mm	70 mm	449 g	1070	n	Apr 2019	599	amazon.com
2.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	1,999	amazon.com
3.		Canon 77D	131 mm	100 mm	76 mm	540 g	600	n	Feb 2017	899	ebay.com
4.		Canon M50	116 mm	88 mm	59 mm	390 g	235	n	Feb 2018	779	ebay.com
5.		Canon M50 Mark II	116 mm	88 mm	59 mm	387 g	305	n	Oct 2020	599	ebay.com
6.		Canon SL1	117 mm	91 mm	69 mm	407 g	380	n	Mar 2013	549	ebay.com
7.		Canon SL2	122 mm	93 mm	70 mm	453 g	650	n	Jun 2017	549	ebay.com
8.		Canon T2i	129 mm	98 mm	62 mm	530 g	440	n	Feb 2010	699	ebay.com
9.		Canon T6s	132 mm	101 mm	78 mm	565 g	440	n	Feb 2015	649	ebay.com
10.		Canon T7	129 mm	101 mm	78 mm	475 g	500	n	Feb 2018	449	amazon.com
11.		Canon T7i	131 mm	100 mm	76 mm	532 g	600	n	Feb 2017	749	ebay.com
12.		Canon T8i	131 mm	103 mm	76 mm	515 g	800	n	Feb 2020	749	ebay.com
13.		Nikon Z6	134 mm	101 mm	67 mm	675 g	310	Y	Aug 2018	1,999	ebay.com
14.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999	ebay.com
15.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	3,199	ebay.com
16.		Sony A7R IV	129 mm	96 mm	78 mm	665 g	670	Y	Jul 2019	3,499	ebay.com
17.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	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 SL3 was launched at a markedly lower price (by 70 percent) than the A7 III, 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 SL3 features an APS-C sensor and the Sony A7 III a full frame sensor. The sensor area in the A7 III is 155 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.

Even though the A7 III has a larger sensor, both cameras offer the same resolution of 24 megapixels. This implies that the A7 III has a lower pixel density and larger individual pixels (with a pixel pitch of 5.94μm versus 3.72μm for the SL3), which gives it a potential advantage in terms of light gathering capacity. It should, however, be noted that the SL3 is a somewhat more recent model (by 1 year and 1 month) than the A7 III, and its sensor might have benefitted from technological advances during this time that at least partly compensate for the smaller pixel size.

The Canon EOS Rebel SL3 has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 100-51200. The corresponding ISO settings for the Sony Alpha A7 III are ISO 100 to ISO 51200, with the possibility to increase the ISO range to 50-204800.

In terms of underlying technology, the SL3 is build around a CMOS sensor, while the A7 III uses a BSI-CMOS imager. 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"). 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 SL3	APS-C	24.0	6000	4000	4K/25p	23.9	13.4	1791	82
2.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
3.		Canon 77D	APS-C	24.0	6000	4000	1080/60p	23.6	13.3	971	78
4.		Canon M50	APS-C	24.0	6000	4000	4K/24p	23.8	13.3	1684	81
5.		Canon M50 Mark II	APS-C	24.0	6000	4000	4K/24p	24.0	13.6	1939	83
6.		Canon SL1	APS-C	17.9	5184	3456	1080/30p	21.8	11.3	843	63
7.		Canon SL2	APS-C	24.0	6000	4000	1080/60p	23.6	13.4	1041	79
8.		Canon T2i	APS-C	17.9	5184	3456	1080/30p	22.1	11.5	784	66
9.		Canon T6s	APS-C	24.0	6000	4000	1080/30p	22.6	12.0	915	70
10.		Canon T7	APS-C	24.0	6000	4000	1080/30p	23.8	13.3	1684	81
11.		Canon T7i	APS-C	24.0	6000	4000	1080/60p	23.7	13.1	1586	80
12.		Canon T8i	APS-C	24.0	6000	4000	4K/24p	24.0	13.5	1873	83
13.		Nikon Z6	Full Frame	24.3	6048	4024	4K/30p	25.3	14.3	3299	95
14.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
15.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
16.		Sony A7R IV	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
17.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
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. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A7 III provides a faster frame rate than the SL3. It can shoot movie footage at 4K/30p, while the Canon is limited to 4K/25p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A7 III has an electronic viewfinder (2359k dots), while the SL3 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 A7 III offers a wider field of view (100%) than the one in the SL3 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A7 III has a higher magnification (0.78x vs 0.54x), 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 SL3 and Sony A7 III 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 SL3	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
2.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
3.		Canon 77D	optical	Y	3.0 / 1040	swivel	Y	1/4000s	6.0/s	Y	n
4.		Canon M50	2360	n	3.0 / 1040	swivel	Y	1/4000s	10.0/s	Y	n
5.		Canon M50 Mark II	2360	n	3.0 / 1040	swivel	Y	1/4000s	10.0/s	Y	n
6.		Canon SL1	optical	n	3.0 / 1040	fixed	Y	1/4000s	4.9/s	Y	n
7.		Canon SL2	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
8.		Canon T2i	optical	n	3.0 / 1040	fixed	n	1/4000s	3.7/s	Y	n
9.		Canon T6s	optical	Y	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
10.		Canon T7	optical	n	3.0 / 920	fixed	n	1/4000s	3.0/s	Y	n
11.		Canon T7i	optical	n	3.0 / 1040	swivel	Y	1/4000s	6.0/s	Y	n
12.		Canon T8i	optical	n	3.0 / 1040	swivel	Y	1/4000s	7.5/s	Y	n
13.		Nikon Z6	3690	Y	3.2 / 2100	tilting	Y	1/8000s	12.0/s	n	Y
14.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
15.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
16.		Sony A7R IV	5760	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
17.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/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 SL3 has one, while the A7 III does not. While the built-in flash of the SL3 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 A7 III 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 Canon SL3 and the Sony A7 III both have an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.

The SL3 writes its imaging data to SDXC cards, while the A7 III uses SDXC or Memory Stick PRO Duo cards. The A7 III features dual card slots, which can be very useful in case a memory card fails. In contrast, the SL3 only has one slot. The A7 III supports UHS-II cards (on its first slot), while the SL3 can use UHS-I 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 Rebel SL3 and Sony Alpha A7 III 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 SL3	Y	stereo / mono	Y	-	mini	2.0	Y	-	Y
2.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
3.		Canon 77D	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
4.		Canon M50	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
5.		Canon M50 Mark II	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
6.		Canon SL1	Y	mono / mono	Y	-	mini	2.0	-	-	-
7.		Canon SL2	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
8.		Canon T2i	Y	stereo / -	Y	-	mini	2.0	-	-	-
9.		Canon T6s	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
10.		Canon T7	Y	mono / mono	-	-	mini	2.0	Y	Y	-
11.		Canon T7i	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
12.		Canon T8i	Y	stereo / mono	Y	-	mini	2.0	Y	-	Y
13.		Nikon Z6	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
14.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
16.		Sony A7R IV	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
17.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y

It is notable that the A7 III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The SL3 lacks such a headphone port.

Both the SL3 and the A7 III are recent models that are part of the current product line-up. The A7 III replaced the earlier Sony A7 II, while the SL3 followed on from the Canon SL2. Further information on the features and operation of the SL3 and A7 III can be found, respectively, in the Canon SL3 Manual (free pdf) or the online Sony A7 III Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Canon SL3 and the Sony A7 III? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Canon EOS Rebel SL3:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• More detailed LCD: Has a higher resolution rear screen (1040k vs 922k dots).
• More flexible LCD: Has a swivel 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.
• Less heavy: Is lighter (by 201g or 31 percent) and hence easier to carry around.
• Longer lasting: Can take more shots (1070 versus 610) 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 (70 percent cheaper at launch).
• More modern: Is somewhat more recent (announced 1 year and 1 month after the A7 III).

Arguments in favor of the Sony Alpha A7 III:

• Better image quality: Features bigger pixels on a larger sensor for higher quality imaging.
• Richer colors: The pixel size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger pixels capture a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger pixels means good image quality even under poor lighting.
• Better video: Provides higher movie framerates (4K/30p versus 4K/25p).
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• 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 (0.78x vs 0.54x).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (10 vs 5 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Easier travel charging: Can be conveniently charged via its USB port.
• 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.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
• More heavily discounted: Has been on the market for longer (launched in February 2018).

If the count of individual advantages (bullet points above) is taken as a guide, the A7 III is the clear winner of the contest (21 : 9 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 SL3 and the Sony A7 III 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 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 SL3 or the A7 III. 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 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 SL3	4/5	o	4.5/5	79/100	4/5	4/5	Apr 2019	599	amazon.com
2.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	1,999	amazon.com
3.		Canon 77D	4.5/5	..	4/5	82/100	4.5/5	4/5	Feb 2017	899	ebay.com
4.		Canon M50	..	+	4/5	79/100	..	3.5/5	Feb 2018	779	ebay.com
5.		Canon M50 Mark II	4/5	..	4/5	..	4.5/5	3.5/5	Oct 2020	599	ebay.com
6.		Canon SL1	4/5	+	..	78/100	4/5	4/5	Mar 2013	549	ebay.com
7.		Canon SL2	4/5	+ +	4/5	78/100	4.5/5	4.5/5	Jun 2017	549	ebay.com
8.		Canon T2i	..	+ +	..	77/100	4/5	4.5/5	Feb 2010	699	ebay.com
9.		Canon T6s	5/5	+	..	77/100	4.5/5	4.5/5	Feb 2015	649	ebay.com
10.		Canon T7	..	o	3.5/5	..	3.5/5	3.5/5	Feb 2018	449	amazon.com
11.		Canon T7i	4.5/5	..	3.5/5	80/100	4.5/5	4/5	Feb 2017	749	ebay.com
12.		Canon T8i	4.5/5	+	3/5	80/100	4/5	3.5/5	Feb 2020	749	ebay.com
13.		Nikon Z6	5/5	..	5/5	89/100	4.5/5	5/5	Aug 2018	1,999	ebay.com
14.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	1,999	ebay.com
15.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	3,199	ebay.com
16.		Sony A7R IV	5/5	+	4.5/5	91/100	4.5/5	5/5	Jul 2019	3,499	ebay.com
17.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	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. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Check SL3 price at
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Check A7 III price at
amazon.com

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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