Olympus E-P3 vs Sony A7

The Olympus PEN E-P3 and the Sony Alpha A7 are two enthusiast cameras that were officially introduced, respectively, in June 2011 and October 2013. Both the E-P3 and the A7 are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-P3) and a full frame (A7) sensor. The Olympus has a resolution of 12.2 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

Olympus E-P3		Sony A7
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Sony E mount lenses
12.2 MP – Four Thirds sensor		24 MP – Full Frame sensor
1080/60i Video		1080/60p Video
ISO 200-12,800		ISO 100-25,600 (50 - 51,200)
Viewfinder optional		Electronic viewfinder (2400k dots)
3.0" LCD – 614k dots		3.0" LCD – 1230k dots
Fixed touchscreen		Tilting screen (no touchscreen)
3 shutter flaps per second		5 shutter flaps per second
In-body stabilization		Lens stabilization only
not weather sealed		Weathersealed body
330 shots per battery charge		340 shots per battery charge
122 x 69 x 34 mm, 369 g		127 x 94 x 48 mm, 474 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus PEN E-P3 and the Sony Alpha A7? 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 side-by-side display below illustrates the physical size and weight of the Olympus E-P3 and the Sony A7. 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.

The E-P3 can be obtained in three different colors (black, silver, white), while the A7 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 is notably larger (42 percent) than the Olympus E-P3. Moreover, the A7 is markedly heavier (28 percent) than the E-P3. It is noteworthy in this context that the A7 is splash and dust-proof, while the E-P3 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 Micro Four Thirds Lens Catalog (E-P3) and the Sony FE Lens Catalog (A7). Mirrorless cameras, such as the two under consideration, have the additional advantage of having a short flange to focal plane distance, which makes it possible to mount many lenses from other systems onto the camera via adapters.

Concerning battery life, the E-P3 gets 330 shots out of its Olympus BLS-5 battery, while the A7 can take 340 images on a single charge of its Sony NP-FW50 power pack. The power pack in the A7 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. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price	Street Price
1.		Olympus E-P3	122 mm	69 mm	34 mm	369 g	330	n	Jun 2011	US$ 799	ebay.com
2.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	US$ 1 699	ebay.com
3.		Olympus E-P1	121 mm	70 mm	36 mm	355 g	300	n	Jun 2009	US$ 799	ebay.com
4.		Olympus E-P2	121 mm	70 mm	36 mm	355 g	300	n	Nov 2009	US$ 799	ebay.com
5.		Olympus E-P5	122 mm	69 mm	37 mm	420 g	330	n	May 2013	US$ 999	ebay.com
6.		Olympus E-PL1	115 mm	72 mm	42 mm	334 g	290	n	Feb 2010	US$ 599	ebay.com
7.		Olympus E-PL2	114 mm	72 mm	42 mm	362 g	280	n	Jan 2011	US$ 599	ebay.com
8.		Olympus E-PL3	110 mm	64 mm	37 mm	313 g	300	n	Jun 2011	US$ 599	ebay.com
9.		Olympus E-PL5	111 mm	64 mm	38 mm	325 g	360	n	Sep 2012	US$ 599	ebay.com
10.		Olympus E-PM1	110 mm	64 mm	34 mm	265 g	330	n	Jun 2011	US$ 499	ebay.com
11.		Panasonic G10	124 mm	84 mm	74 mm	388 g	380	n	Mar 2010	US$ 499	ebay.com
12.		Panasonic GX1	116 mm	68 mm	39 mm	318 g	320	n	Nov 2011	US$ 699	ebay.com
13.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	US$ 1 999	ebay.com
14.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	US$ 2 299	ebay.com
15.		Sony A7S	127 mm	94 mm	48 mm	489 g	380	Y	Apr 2014	US$ 2 499	ebay.com
16.		Sony RX1	113 mm	65 mm	70 mm	482 g	270	n	Sep 2012	US$ 2 799	ebay.com
17.		Sony RX1R	113 mm	65 mm	70 mm	482 g	270	n	Jun 2013	US$ 2 799	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 naturally be influenced heavily by the price. 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 E-P3 was launched at a markedly lower price (by 53 percent) than the A7, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Olympus E-P3 features a Four Thirds sensor and the Sony A7 a full frame sensor. The sensor area in the A7 is 280 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.0. The sensor in the E-P3 has a native 4:3 aspect ratio, while the one in the A7 offers a 3:2 aspect.

With 24MP, the A7 offers a higher resolution than the E-P3 (12.2MP), but the A7 nevertheless has larger individual pixels (pixel pitch of 5.97μm versus 4.29μm for the E-P3) due to its larger sensor. Moreover, the A7 is a much more recent model (by 2 years and 3 months) than the E-P3, 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 A7 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7 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 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 A7 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Olympus PEN E-P3 has a native sensitivity range from ISO 200 to ISO 12800. The corresponding ISO settings for the Sony Alpha A7 are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-51200.

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 consideration, the A7 offers substantially better image quality than the E-P3 (overall score 39 points higher). The advantage is based on 4 bits higher color depth, 4.1 EV in additional dynamic range, and 2.1 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.		Olympus E-P3	Four Thirds	12.2	4032	3024	1080/60i	20.8	10.1	536	51
2.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90
3.		Olympus E-P1	Four Thirds	12.2	4032	3024	720/30p	21.4	10.4	536	55
4.		Olympus E-P2	Four Thirds	12.2	4032	3024	720/30p	21.5	10.4	505	56
5.		Olympus E-P5	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.4	895	72
6.		Olympus E-PL1	Four Thirds	12.2	4032	3024	720/30p	21.5	10.1	487	54
7.		Olympus E-PL2	Four Thirds	12.2	4032	3024	720/30p	21.4	10.2	573	55
8.		Olympus E-PL3	Four Thirds	12.2	4032	3024	1080/60i	20.9	10.3	499	52
9.		Olympus E-PL5	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.3	889	72
10.		Olympus E-PM1	Four Thirds	12.2	4032	3024	1080/60i	21.0	10.3	499	52
11.		Panasonic G10	Four Thirds	12.0	4000	3000	720/30p	21.2	10.1	411	52
12.		Panasonic GX1	Four Thirds	15.8	4592	3448	1080/60p	20.8	10.6	703	55
13.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
14.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95
15.		Sony A7S	Full Frame	12.0	4240	2832	1080/60p	23.9	13.2	3702	87
16.		Sony RX1	Full Frame	24.0	6000	4000	1080/60p	25.1	14.3	2534	93
17.		Sony RX1R	Full Frame	24.0	6000	4000	1080/60p	25.0	13.6	2537	91

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A7 provides a faster frame rate than the E-P3. It can shoot movie footage at 1080/60p, while the Olympus is limited to 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A7 has an electronic viewfinder (2400k dots), which can be very helpful 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 Olympus E-P3, the Sony A7, 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.		Olympus E-P3	optional	n	3.0 / 614	fixed	Y	1/4000s	3.0/s	Y	Y
2.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
3.		Olympus E-P1	none	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
4.		Olympus E-P2	optional	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
5.		Olympus E-P5	optional	n	3.0 / 1037	tilting	Y	1/8000s	9.0/s	Y	Y
6.		Olympus E-PL1	optional	n	2.7 / 230	fixed	n	1/2000s	3.0/s	Y	Y
7.		Olympus E-PL2	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	Y
8.		Olympus E-PL3	optional	n	3.0 / 460	tilting	n	1/4000s	5.5/s	n	Y
9.		Olympus E-PL5	optional	n	3.0 / 460	tilting	Y	1/4000s	8.0/s	n	Y
10.		Olympus E-PM1	optional	n	3.0 / 460	fixed	n	1/4000s	5.5/s	n	Y
11.		Panasonic G10	202	n	3.0 / 460	fixed	n	1/4000s	2.6/s	Y	n
12.		Panasonic GX1	optional	n	3.0 / 460	fixed	Y	1/4000s	4.2/s	Y	n
13.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
14.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
15.		Sony A7S	2400	n	3.0 / 921	tilting	n	1/8000s	5.0/s	n	n
16.		Sony RX1	optional	n	3.0 / 1229	fixed	n	1/4000s	5.0/s	Y	n
17.		Sony RX1R	optional	n	3.0 / 1229	fixed	n	1/4000s	5.0/s	Y	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 E-P3 has one, while the A7 does not. While the built-in flash of the E-P3 is not very powerful, it can at times be useful as a fill-in light.

The E-P3 writes its imaging data to SDXC cards, while the A7 uses SDXC or Memory Stick PRO Duo cards. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.

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 Olympus PEN E-P3 and Sony Alpha A7 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.		Olympus E-P3	Y	stereo / -	-	-	mini	2.0	-	-	-
2.		Sony A7	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
3.		Olympus E-P1	Y	stereo / -	-	-	mini	2.0	-	-	-
4.		Olympus E-P2	Y	stereo / -	-	-	mini	2.0	-	-	-
5.		Olympus E-P5	Y	stereo / mono	-	-	micro	2.0	Y	-	-
6.		Olympus E-PL1	Y	stereo / -	-	-	mini	2.0	-	-	-
7.		Olympus E-PL2	Y	stereo / -	-	-	mini	2.0	-	-	-
8.		Olympus E-PL3	Y	stereo / -	-	-	mini	2.0	-	-	-
9.		Olympus E-PL5	Y	stereo / mono	-	-	mini	2.0	-	-	-
10.		Olympus E-PM1	Y	stereo / mono	-	-	mini	2.0	-	-	-
11.		Panasonic G10	Y	mono / -	-	-	mini	2.0	-	-	-
12.		Panasonic GX1	Y	stereo / mono	-	-	mini	2.0	-	-	-
13.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
14.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A7S	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony RX1	Y	stereo / mono	Y	-	mini	2.0	-	-	-
17.		Sony RX1R	Y	stereo / mono	Y	-	mini	2.0	-	-	-

It is notable that the A7 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the E-P3 does not provide wifi capability.

Both the E-P3 and the A7 have been discontinued, but can regularly be found used on ebay. The E-P3 was replaced by the Olympus E-P5, while the A7 was followed by the Sony A7 II. Further information on the features and operation of the E-P3 and A7 can be found, respectively, in the Olympus E-P3 Manual (free pdf) or the online Sony A7 Manual.

Review summary

So how do things add up? Is the Olympus E-P3 better than the Sony A7 or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Olympus PEN E-P3:

• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• More compact: Is smaller (122x69mm vs 127x94mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 105g or 22 percent) and hence easier to carry around.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (53 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in June 2011).

Reasons to prefer the Sony Alpha A7:

• More detail: Has more megapixels (24 vs 12.2MP), which boosts linear resolution by 43%.
• Better image quality: Scores substantially higher (39 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (4 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (4.1 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (2.1 stops ISO advantage).
• Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Better sound: Can connect to an external microphone for higher quality sound recording.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• Easier framing: Has an electronic viewfinder for image composition and settings control.
• More detailed LCD: Has a higher resolution rear screen (1230k vs 614k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (5 vs 3 flaps/sec) to capture the decisive moment.
• Easier travel charging: Can be conveniently charged via its USB port.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• 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 2 years and 3 months of technical progress since the E-P3 launch.

If the count of relative strengths (bullet points above) is taken as a measure, the A7 is the clear winner of the contest (19 : 7 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 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 Olympus E-P3 and the Sony A7 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera listing 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 partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the E-P3 or the A7. 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	Street Price
1.		Olympus E-P3	..	83/100	..	74/100	4.5/5	4.5/5	Jun 2011	US$ 799	ebay.com
2.		Sony A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	US$ 1 699	ebay.com
3.		Olympus E-P1	..	+	..	66/100	4/5	4.5/5	Jun 2009	US$ 799	ebay.com
4.		Olympus E-P2	3/5	+	..	69/100	4/5	4.5/5	Nov 2009	US$ 799	ebay.com
5.		Olympus E-P5	5/5	+ +	..	78/100	4.5/5	5/5	May 2013	US$ 999	ebay.com
6.		Olympus E-PL1	..	86/100	..	69/100	4/5	4.5/5	Feb 2010	US$ 599	ebay.com
7.		Olympus E-PL2	3/5	83/100	..	71/100	4.5/5	4.5/5	Jan 2011	US$ 599	ebay.com
8.		Olympus E-PL3	3/5	+ +	..	72/100	4.5/5	4/5	Jun 2011	US$ 599	ebay.com
9.		Olympus E-PL5	3/5	+ +	..	..	4.5/5	4.5/5	Sep 2012	US$ 599	ebay.com
10.		Olympus E-PM1	..	86/100	..	71/100	4.5/5	4.5/5	Jun 2011	US$ 499	ebay.com
11.		Panasonic G10	3/5	..	..	70/100	4/5	4/5	Mar 2010	US$ 499	ebay.com
12.		Panasonic GX1	3/5	+	..	77/100	4.5/5	4.5/5	Nov 2011	US$ 699	ebay.com
13.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	US$ 1 999	ebay.com
14.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	US$ 2 299	ebay.com
15.		Sony A7S	4/5	..	..	86/100	4.5/5	5/5	Apr 2014	US$ 2 499	ebay.com
16.		Sony RX1	5/5	..	..	79/100	4/5	4.5/5	Sep 2012	US$ 2 799	ebay.com
17.		Sony RX1R	5/5	..	..	..	4/5	4.5/5	Jun 2013	US$ 2 799	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, 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.

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Other camera comparisons

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