Olympus E-P1 vs Sony A7S

The Olympus PEN E-P1 and the Sony Alpha A7S are two digital cameras that were announced, respectively, in June 2009 and April 2014. Both the E-P1 and the A7S are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-P1) and a full frame (A7S) sensor. The Olympus has a resolution of 12.2 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

Olympus E-P1		Sony A7S
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Sony E mount lenses
12.2 MP – Four Thirds sensor		12 MP – Full Frame sensor
720/30p Video		1080/60p Video
ISO 100-6,400		ISO 100-102,400 (50 - 409,600)
No viewfinder, LCD framing		Electronic viewfinder (2400k dots)
3.0" LCD – 230k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		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
300 shots per battery charge		380 shots per battery charge
121 x 70 x 36 mm, 355 g		127 x 94 x 48 mm, 489 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus PEN E-P1 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

The side-by-side display below illustrates the physical size and weight of the Olympus E-P1 and the Sony A7S. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth dimensions are rounded to the nearest millimeter.

The E-P1 can be obtained in three different colors (black, silver, white), while the A7S 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 A7S is notably larger (41 percent) than the Olympus E-P1. Moreover, the A7S is substantially heavier (38 percent) than the E-P1. It is noteworthy in this context that the A7S is splash and dust-proof, while the E-P1 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-P1) and the Sony FE Lens Catalog (A7S). 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-P1 gets 300 shots out of its Olympus BLS-1 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 table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.		Olympus E-P1	121 mm	70 mm	36 mm	355 g	300	n	Jun 2009	799	ebay.com
2.		Sony A7S	127 mm	94 mm	48 mm	489 g	380	Y	Apr 2014	2,499	ebay.com
3.		Nikon Df	144 mm	110 mm	67 mm	760 g	1400	Y	Nov 2013	2,749	ebay.com
4.		Olympus E-520	136 mm	92 mm	68 mm	535 g	750	n	May 2008	699	ebay.com
5.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	699	ebay.com
6.		Olympus E-P2	121 mm	70 mm	36 mm	355 g	300	n	Nov 2009	799	ebay.com
7.		Olympus E-P3	122 mm	69 mm	34 mm	369 g	330	n	Jun 2011	799	ebay.com
8.		Olympus E-PL1	115 mm	72 mm	42 mm	334 g	290	n	Feb 2010	599	ebay.com
9.		Olympus E-PL2	114 mm	72 mm	42 mm	362 g	280	n	Jan 2011	599	ebay.com
10.		Olympus E-PL3	110 mm	64 mm	37 mm	313 g	300	n	Jun 2011	599	ebay.com
11.		Panasonic G10	124 mm	84 mm	74 mm	388 g	380	n	Mar 2010	499	ebay.com
12.		Panasonic GF1	119 mm	71 mm	36 mm	385 g	380	n	Sep 2009	749	ebay.com
13.		Panasonic GH1	124 mm	90 mm	45 mm	385 g	300	n	Mar 2009	899	ebay.com
14.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	1,699	ebay.com
15.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	2,299	ebay.com
16.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
17.		Sony ZV-E1	121 mm	72 mm	54 mm	483 g	570	Y	Mar 2023	2,199	amazon.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 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 E-P1 was launched at a markedly lower price (by 68 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. 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 imaging sensor is a crucial determinant 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Olympus E-P1 features a Four Thirds sensor and the Sony A7S a full frame sensor. The sensor area in the A7S 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-P1 has a native 4:3 aspect ratio, while the one in the A7S offers a 3:2 aspect.

Despite having a smaller sensor, the Olympus E-P1 offers a higher resolution of 12.2 megapixels, compared with 12 MP of the Sony A7S. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 4.29μm versus 8.45μm for the A7S). Moreover, it should be noted that the A7S is much more recent (by 4 years and 9 months) than the E-P1, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units.

The Olympus PEN E-P1 has a native sensitivity range from ISO 100 to ISO 6400. 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.

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 A7S offers substantially better image quality than the E-P1 (overall score 32 points higher). The advantage is based on 2.5 bits higher color depth, 2.8 EV in additional dynamic range, and 2.8 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-P1	Four Thirds	12.2	4032	3024	720/30p	21.4	10.4	536	55
2.		Sony A7S	Full Frame	12.0	4240	2832	1080/60p	23.9	13.2	3702	87
3.		Nikon Df	Full Frame	16.2	4928	3280	none	24.6	13.1	3279	89
4.		Olympus E-520	Four Thirds	10.0	3648	2736	none	21.4	10.4	548	55
5.		Olympus E-620	Four Thirds	12.2	4032	3024	none	21.3	10.3	536	55
6.		Olympus E-P2	Four Thirds	12.2	4032	3024	720/30p	21.5	10.4	505	56
7.		Olympus E-P3	Four Thirds	12.2	4032	3024	1080/60i	20.8	10.1	536	51
8.		Olympus E-PL1	Four Thirds	12.2	4032	3024	720/30p	21.5	10.1	487	54
9.		Olympus E-PL2	Four Thirds	12.2	4032	3024	720/30p	21.4	10.2	573	55
10.		Olympus E-PL3	Four Thirds	12.2	4032	3024	1080/60i	20.9	10.3	499	52
11.		Panasonic G10	Four Thirds	12.0	4000	3000	720/30p	21.2	10.1	411	52
12.		Panasonic GF1	Four Thirds	12.0	4000	3000	720/30p	21.2	10.3	513	54
13.		Panasonic GH1	Four Thirds	12.0	4000	3000	1080/24p	21.6	11.6	772	64
14.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90
15.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95
16.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
17.		Sony ZV-E1	Full Frame	12.0	4240	2832	4K/60p	25.4	14.6	3181	96
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 two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A7S provides a better video resolution than the E-P1. It can shoot movie footage at 1080/60p, while the Olympus is limited to 720/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A7S has an electronic viewfinder (2400k dots), which can be very helpful when shooting in bright sunlight. In contrast, the E-P1 relies on live view and the rear LCD for framing. The adjacent table lists some of the other core features of the Olympus E-P1 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.		Olympus E-P1	none	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
2.		Sony A7S	2400	n	3.0 / 921	tilting	n	1/8000s	5.0/s	n	n
3.		Nikon Df	optical	Y	3.2 / 921	fixed	n	1/4000s	5.5/s	n	n
4.		Olympus E-520	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	Y
5.		Olympus E-620	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
6.		Olympus E-P2	optional	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
7.		Olympus E-P3	optional	n	3.0 / 614	fixed	Y	1/4000s	3.0/s	Y	Y
8.		Olympus E-PL1	optional	n	2.7 / 230	fixed	n	1/2000s	3.0/s	Y	Y
9.		Olympus E-PL2	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	Y
10.		Olympus E-PL3	optional	n	3.0 / 460	tilting	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 GF1	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	n
13.		Panasonic GH1	1440	n	3.0 / 460	swivel	n	1/4000s	3.0/s	Y	n
14.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
15.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
16.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
17.		Sony ZV-E1	none	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the E-P1 and the A7S is in-body image stabilization (IBIS). The E-P1 reduces the risk of handshake-induced blur with all attached lenses, while the A7S offers no blur reduction with lenses that themselves do not provide optical image stabilization.

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 E-P1 writes its imaging data to SDHC cards, while the A7S uses SDXC or Memory Stick PRO Duo cards. The A7S supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the E-P1 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 Olympus PEN E-P1 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.		Olympus E-P1	Y	stereo / -	-	-	mini	2.0	-	-	-
2.		Sony A7S	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
3.		Nikon Df	Y	- / -	-	-	mini	2.0	-	-	-
4.		Olympus E-520	Y	- / -	-	-	-	2.0	-	-	-
5.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
6.		Olympus E-P2	Y	stereo / -	-	-	mini	2.0	-	-	-
7.		Olympus E-P3	Y	stereo / -	-	-	mini	2.0	-	-	-
8.		Olympus E-PL1	Y	stereo / -	-	-	mini	2.0	-	-	-
9.		Olympus E-PL2	Y	stereo / -	-	-	mini	2.0	-	-	-
10.		Olympus E-PL3	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Panasonic G10	Y	mono / -	-	-	mini	2.0	-	-	-
12.		Panasonic GF1	Y	mono / mono	-	-	mini	2.0	-	-	-
13.		Panasonic GH1	Y	stereo / -	Y	-	mini	2.0	-	-	-
14.		Sony A7	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony ZV-E1	Y	stereo / mono	Y	Y	micro	3.2	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 E-P1 does not provide wifi capability.

Both the E-P1 and the A7S have been discontinued, but can regularly be found used on ebay. The E-P1 was replaced by the Olympus E-P2, while the A7S was followed by the Sony A7S II. Further information on the features and operation of the E-P1 and A7S can be found, respectively, in the Olympus E-P1 Manual (free pdf) or the online Sony A7S Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Olympus E-P1 or the Sony A7S – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Olympus PEN E-P1:

• More compact: Is smaller (121x70mm vs 127x94mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 134g or 27 percent) and hence easier to carry around.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• More affordable: Was introduced into a lower priced category (68 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in June 2009).

Advantages of the Sony Alpha A7S:

• Better image quality: Scores substantially higher (32 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.5 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.8 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (2.8 stops ISO advantage).
• Better video: Provides higher definition movie capture (1080/60p vs 720/30p).
• 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 (921k vs 230k 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.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Longer lasting: Gets more shots (380 versus 300) out of a single battery charge.
• 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.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Reflects 4 years and 9 months of technical progress since the E-P1 launch.

If the count of relative strengths (bullet points above) is taken as a measure, the A7S is the clear winner of the contest (20 : 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 Olympus E-P1 and the Sony A7S 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 incomplete and does no justice, for example, to the way the E-P1 or the A7S perform in practice. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.

Expert reviews

This is where reviews by experts come in. The adjacent summary-table relays the overall verdicts of several of the most popular camera 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.		Olympus E-P1	..	+	..	66/100	4/5	4.5/5	Jun 2009	799	ebay.com
2.		Sony A7S	4/5	..	..	86/100	4.5/5	5/5	Apr 2014	2,499	ebay.com
3.		Nikon Df	4/5	..	..	81/100	4/5	4/5	Nov 2013	2,749	ebay.com
4.		Olympus E-520	..	87/100	..	+ +	4.5/5	4.5/5	May 2008	699	ebay.com
5.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	699	ebay.com
6.		Olympus E-P2	3/5	+	..	69/100	4/5	4.5/5	Nov 2009	799	ebay.com
7.		Olympus E-P3	..	83/100	..	74/100	4.5/5	4.5/5	Jun 2011	799	ebay.com
8.		Olympus E-PL1	..	86/100	..	69/100	4/5	4.5/5	Feb 2010	599	ebay.com
9.		Olympus E-PL2	3/5	83/100	..	71/100	4.5/5	4.5/5	Jan 2011	599	ebay.com
10.		Olympus E-PL3	3/5	+ +	..	72/100	4.5/5	4/5	Jun 2011	599	ebay.com
11.		Panasonic G10	3/5	..	..	70/100	4/5	4/5	Mar 2010	499	ebay.com
12.		Panasonic GF1	..	85/100	..	69/100	4.5/5	4.5/5	Sep 2009	749	ebay.com
13.		Panasonic GH1	..	+ +	..	72/100	4.5/5	4.5/5	Mar 2009	899	ebay.com
14.		Sony A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	1,699	ebay.com
15.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	2,299	ebay.com
16.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
17.		Sony ZV-E1	..	+	4/5	..	..	4.5/5	Mar 2023	2,199	amazon.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 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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