Canon T3i vs Olympus E-P3

The Canon EOS Rebel T3i (called Canon 600D in some regions) and the Olympus PEN E-P3 are two digital cameras that were officially introduced, respectively, in February 2011 and June 2011. The T3i is a DSLR, while the E-P3 is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (T3i) and a Four Thirds (E-P3) sensor. The Canon has a resolution of 17.9 megapixels, whereas the Olympus provides 12.2 MP.

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

Headline Specifications

Canon T3i		Olympus E-P3
Digital single lens reflex		Mirrorless system camera
Canon EF mount lenses		Micro Four Thirds lenses
17.9 MP – APS-C sensor		12.2 MP – Four Thirds sensor
1080/30p Video		1080/60i Video
ISO 100-6,400 (100 - 12,800)		ISO 200-12,800
Optical viewfinder		Viewfinder optional
3.0" LCD – 1040k dots		3.0" LCD – 614k dots
Swivel screen (not touch-sensitive)		Fixed touchscreen
3.7 shutter flaps per second		3 shutter flaps per second
Lens stabilization only		In-body stabilization
440 shots per battery charge		330 shots per battery charge
133 x 100 x 80 mm, 570 g		122 x 69 x 34 mm, 369 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS Rebel T3i and the Olympus PEN E-P3? 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 T3i and the Olympus E-P3 are illustrated 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 measures are rounded to the nearest millimeter.

The E-P3 can be obtained in three different colors (black, silver, white), while the T3i 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 Olympus E-P3 is considerably smaller (37 percent) than the Canon T3i. Moreover, the E-P3 is substantially lighter (35 percent) than the T3i. In this context, it is worth noting that neither the T3i nor the E-P3 are weather-sealed.

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 (T3i) and the Micro Four Thirds Lens Catalog (E-P3). Mirrorless cameras, such as the E-P3, 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 T3i gets 440 shots out of its Canon LP-E8 battery, while the E-P3 can take 330 images on a single charge of its Olympus BLS-5 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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 T3i	133 mm	100 mm	80 mm	570 g	440	n	Feb 2011	599	ebay.com
2.		Olympus E-P3	122 mm	69 mm	34 mm	369 g	330	n	Jun 2011	799	ebay.com
3.		Canon M	109 mm	66 mm	32 mm	298 g	230	n	Jul 2012	599	ebay.com
4.		Canon SL1	117 mm	91 mm	69 mm	407 g	380	n	Mar 2013	549	ebay.com
5.		Canon T1i	129 mm	98 mm	62 mm	520 g	400	n	Mar 2009	799	ebay.com
6.		Canon T2i	129 mm	98 mm	62 mm	530 g	440	n	Feb 2010	699	ebay.com
7.		Canon T3	130 mm	100 mm	78 mm	495 g	700	n	Feb 2011	449	ebay.com
8.		Canon T4i	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	849	ebay.com
9.		Canon T5	130 mm	100 mm	78 mm	480 g	500	n	Feb 2014	449	ebay.com
10.		Canon T5i	133 mm	100 mm	79 mm	580 g	440	n	Mar 2013	649	ebay.com
11.		Canon T6	129 mm	101 mm	78 mm	485 g	500	n	Mar 2016	449	ebay.com
12.		Canon T6s	132 mm	101 mm	78 mm	565 g	440	n	Feb 2015	649	ebay.com
13.		Olympus E-P1	121 mm	70 mm	36 mm	355 g	300	n	Jun 2009	799	ebay.com
14.		Olympus E-P2	121 mm	70 mm	36 mm	355 g	300	n	Nov 2009	799	ebay.com
15.		Olympus E-PL1	115 mm	72 mm	42 mm	334 g	290	n	Feb 2010	599	ebay.com
16.		Olympus E-PL2	114 mm	72 mm	42 mm	362 g	280	n	Jan 2011	599	ebay.com
17.		Olympus E-PL3	110 mm	64 mm	37 mm	313 g	300	n	Jun 2011	599	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The T3i was launched at a somewhat lower price (by 25 percent) than the E-P3, which makes it more attractive for photographers on a tight budget. 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 sensor inside a digital camera is one of the key determinants 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. 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 T3i features an APS-C sensor and the Olympus E-P3 a Four Thirds sensor. The sensor area in the E-P3 is 32 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.6 and 2.0. The sensor in the T3i has a native 3:2 aspect ratio, while the one in the E-P3 offers a 4:3 aspect.

With 17.9MP, the T3i offers a higher resolution than the E-P3 (12.2MP), but the T3i nevertheless has marginally larger individual pixels (pixel pitch of 4.31μm versus 4.29μm for the E-P3) due to its larger sensor. However, the E-P3 is a somewhat more recent model (by 4 months) than the T3i, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels.

The resolution advantage of the Canon T3i implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the T3i for good quality output (200 dots per inch) amounts to 25.9 x 17.3 inches or 65.8 x 43.9 cm, for very good quality (250 dpi) 20.7 x 13.8 inches or 52.7 x 35.1 cm, and for excellent quality (300 dpi) 17.3 x 11.5 inches or 43.9 x 29.3 cm. The corresponding values for the Olympus E-P3 are 20.2 x 15.1 inches or 51.2 x 38.4 cm for good quality, 16.1 x 12.1 inches or 41 x 30.7 cm for very good quality, and 13.4 x 10.1 inches or 34.1 x 25.6 cm for excellent quality prints.

The Canon EOS Rebel T3i has a native sensitivity range from ISO 100 to ISO 6400, which can be extended to ISO 100-12800. The corresponding ISO settings for the Olympus PEN E-P3 are ISO 200 to ISO 12800 (no boost).

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 assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. Of the two cameras under review, the T3i provides substantially higher image quality than the E-P3, with an overall score that is 14 points higher. This advantage is based on 1.3 bits higher color depth, 1.4 EV in additional dynamic range, and 0.6 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 T3i	APS-C	17.9	5184	3456	1080/30p	22.1	11.5	793	65
2.		Olympus E-P3	Four Thirds	12.2	4032	3024	1080/60i	20.8	10.1	536	51
3.		Canon M	APS-C	17.9	5184	3456	1080/30p	22.1	11.2	827	65
4.		Canon SL1	APS-C	17.9	5184	3456	1080/30p	21.8	11.3	843	63
5.		Canon T1i	APS-C	15.1	4752	3168	1080/20p	21.7	11.5	663	63
6.		Canon T2i	APS-C	17.9	5184	3456	1080/30p	22.1	11.5	784	66
7.		Canon T3	APS-C	12.2	4272	2848	720/30p	21.9	11.0	755	62
8.		Canon T4i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
9.		Canon T5	APS-C	17.9	5184	3456	1080/30p	21.9	11.3	724	63
10.		Canon T5i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	681	61
11.		Canon T6	APS-C	17.9	5184	3456	1080/30p	22.0	11.7	781	66
12.		Canon T6s	APS-C	24.0	6000	4000	1080/30p	22.6	12.0	915	70
13.		Olympus E-P1	Four Thirds	12.2	4032	3024	720/30p	21.4	10.4	536	55
14.		Olympus E-P2	Four Thirds	12.2	4032	3024	720/30p	21.5	10.4	505	56
15.		Olympus E-PL1	Four Thirds	12.2	4032	3024	720/30p	21.5	10.1	487	54
16.		Olympus E-PL2	Four Thirds	12.2	4032	3024	720/30p	21.4	10.2	573	55
17.		Olympus E-PL3	Four Thirds	12.2	4032	3024	1080/60i	20.9	10.3	499	52

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the E-P3 provides a faster frame rate than the T3i. It can shoot movie footage at 1080/60i, while the Canon is limited to 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the T3i has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the E-P3 relies on live view and the rear LCD for framing. That said, the E-P3 can be equipped with an optional viewfinder – the VF-3. The following table reports on some other key feature differences and similarities of the Canon T3i, the Olympus E-P3, 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 T3i	optical	n	3.0 / 1040	swivel	n	1/4000s	3.7/s	Y	n
2.		Olympus E-P3	optional	n	3.0 / 614	fixed	Y	1/4000s	3.0/s	Y	Y
3.		Canon M	none	n	3.0 / 1040	fixed	Y	1/4000s	4.3/s	n	n
4.		Canon SL1	optical	n	3.0 / 1040	fixed	Y	1/4000s	4.9/s	Y	n
5.		Canon T1i	optical	n	3.0 / 920	fixed	n	1/4000s	3.4/s	Y	n
6.		Canon T2i	optical	n	3.0 / 1040	fixed	n	1/4000s	3.7/s	Y	n
7.		Canon T3	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
8.		Canon T4i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
9.		Canon T5	optical	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	n
10.		Canon T5i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
11.		Canon T6	optical	n	3.0 / 920	fixed	n	1/4000s	3.0/s	Y	n
12.		Canon T6s	optical	Y	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
13.		Olympus E-P1	none	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
14.		Olympus E-P2	optional	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
15.		Olympus E-PL1	optional	n	2.7 / 230	fixed	n	1/2000s	3.0/s	Y	Y
16.		Olympus E-PL2	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	Y
17.		Olympus E-PL3	optional	n	3.0 / 460	tilting	n	1/4000s	5.5/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The E-P3 has a touchscreen, while the T3i has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

Concerning the storage of imaging data, both the T3i and the E-P3 write their files to SDXC cards. The E-P3 supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the T3i cannot take advantage of Ultra High Speed SD 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 T3i and Olympus PEN E-P3 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 T3i	Y	mono / mono	Y	-	mini	2.0	-	-	-
2.		Olympus E-P3	Y	stereo / -	-	-	mini	2.0	-	-	-
3.		Canon M	Y	stereo / mono	Y	-	mini	2.0	-	-	-
4.		Canon SL1	Y	mono / mono	Y	-	mini	2.0	-	-	-
5.		Canon T1i	Y	mono / mono	-	-	mini	2.0	-	-	-
6.		Canon T2i	Y	stereo / -	Y	-	mini	2.0	-	-	-
7.		Canon T3	Y	stereo / mono	-	-	mini	2.0	-	-	-
8.		Canon T4i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
9.		Canon T5	Y	mono / mono	-	-	mini	2.0	-	-	-
10.		Canon T5i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
11.		Canon T6	Y	mono / mono	-	-	mini	2.0	Y	Y	-
12.		Canon T6s	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
13.		Olympus E-P1	Y	stereo / -	-	-	mini	2.0	-	-	-
14.		Olympus E-P2	Y	stereo / -	-	-	mini	2.0	-	-	-
15.		Olympus E-PL1	Y	stereo / -	-	-	mini	2.0	-	-	-
16.		Olympus E-PL2	Y	stereo / -	-	-	mini	2.0	-	-	-
17.		Olympus E-PL3	Y	stereo / -	-	-	mini	2.0	-	-	-

It is notable that the T3i has a microphone port, which is missing on the E-P3. Such an external microphone input can help to substantially improve the quality of audio recordings when a good external microphone is used.

Both the T3i and the E-P3 have been discontinued, but can regularly be found used on ebay. The T3i was replaced by the Canon T4i, while the E-P3 was followed by the Olympus E-P5. Further information on the features and operation of the T3i and E-P3 can be found, respectively, in the Canon T3i Manual (free pdf) or the online Olympus E-P3 Manual.

Review summary

So what is the bottom line? Is there a clear favorite between the Canon T3i and the Olympus E-P3? 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 Rebel T3i:

• More detail: Offers more megapixels (17.9 vs 12.2MP) with a 24% higher linear resolution.
• Better image quality: Scores substantially higher (14 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (1.3 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (1.4 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (0.6 stops ISO advantage).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• Easier framing: Has an optical viewfinder for image composition and settings control.
• More detailed LCD: Has a higher resolution rear screen (1040k vs 614k 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.
• Faster burst: Shoots at higher frequency (3.7 vs 3 flaps/sec) to capture the decisive moment.
• Longer lasting: Can take more shots (440 versus 330) on a single battery charge.
• More affordable: Was introduced into a lower priced segment (25 percent cheaper at launch).
• More heavily discounted: Has been on the market for longer (launched in February 2011).

Arguments in favor of the Olympus PEN E-P3:

• Better video: Provides higher movie framerates (1080/60i versus 1080/30p).
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• More compact: Is smaller (122x69mm vs 133x100mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 201g or 35 percent) and is thus easier to take along.
• 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 buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Was introduced somewhat (4 months) more recently.

If the count of individual advantages (bullet points above) is taken as a guide, the T3i is the clear winner of the match-up (14 : 8 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 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 T3i and the Olympus E-P3 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 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 T3i and the E-P3 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 T3i	3/5	o	..	77/100	4.5/5	4.5/5	Feb 2011	599	ebay.com
2.		Olympus E-P3	..	83/100	..	74/100	4.5/5	4.5/5	Jun 2011	799	ebay.com
3.		Canon M	3/5	+	..	..	4/5	4/5	Jul 2012	599	ebay.com
4.		Canon SL1	4/5	+	..	78/100	4/5	4/5	Mar 2013	549	ebay.com
5.		Canon T1i	..	+ +	..	74/100	4.5/5	4.5/5	Mar 2009	799	ebay.com
6.		Canon T2i	..	+ +	..	77/100	4/5	4.5/5	Feb 2010	699	ebay.com
7.		Canon T3	..	80/100	..	69/100	4/5	4.5/5	Feb 2011	449	ebay.com
8.		Canon T4i	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	849	ebay.com
9.		Canon T5	3/5	+	..	..	4/5	4.5/5	Feb 2014	449	ebay.com
10.		Canon T5i	..	..	..	76/100	4.5/5	4.5/5	Mar 2013	649	ebay.com
11.		Canon T6	4/5	o	4/5	73/100	4/5	4/5	Mar 2016	449	ebay.com
12.		Canon T6s	5/5	+	..	77/100	4.5/5	4.5/5	Feb 2015	649	ebay.com
13.		Olympus E-P1	..	+	..	66/100	4/5	4.5/5	Jun 2009	799	ebay.com
14.		Olympus E-P2	3/5	+	..	69/100	4/5	4.5/5	Nov 2009	799	ebay.com
15.		Olympus E-PL1	..	86/100	..	69/100	4/5	4.5/5	Feb 2010	599	ebay.com
16.		Olympus E-PL2	3/5	83/100	..	71/100	4.5/5	4.5/5	Jan 2011	599	ebay.com
17.		Olympus E-PL3	3/5	+ +	..	72/100	4.5/5	4/5	Jun 2011	599	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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, 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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Other camera comparisons

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