Olympus E-520 vs Sony A7S II

The Olympus E-520 and the Sony Alpha 7S II are two digital cameras that were officially introduced, respectively, in May 2008 and September 2015. The E-520 is a DSLR, while the A7S II is a mirrorless interchangeable lens camera. The cameras are based on a Four Thirds (E-520) and a full frame (A7S II) sensor. The Olympus has a resolution of 10 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-520		Sony A7S II
Digital single lens reflex		Mirrorless system camera
Four Thirds lenses		Sony E mount lenses
10 MP – Four Thirds sensor		12 MP – Full Frame sensor
no Video		4K/30p Video
ISO 100-1,600		ISO 100-102,400 (50 - 409,600)
Optical viewfinder		Electronic viewfinder (2400k dots)
2.7" LCD – 215k dots		3.0" LCD – 1229k dots
Fixed screen (not touch-sensitive)		Tilting screen (no touchscreen)
3.5 shutter flaps per second		5 shutter flaps per second
In-body stabilization		In-body stabilization
not weather sealed		Weathersealed body
750 shots per battery charge		370 shots per battery charge
136 x 92 x 68 mm, 535 g		127 x 96 x 60 mm, 627 g

Check E-520 offers at
ebay.com
Check A7S II offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus E-520 and the Sony Alpha 7S II? 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-520 and the Sony A7S II. 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 measures 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 II is somewhat smaller (3 percent) than the Olympus E-520. However, the A7S II is markedly heavier (17 percent) than the E-520. It is noteworthy in this context that the A7S II is splash and dust-proof, while the E-520 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 Four Thirds Lens Catalog (E-520) and the Sony FE Lens Catalog (A7S II). Mirrorless cameras, such as the A7S II, 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 E-520 gets 750 shots out of its Olympus BLM-1 battery, while the A7S II can take 370 images on a single charge of its Sony NP-FW50 power pack. The power pack in the A7S II can be charged via the USB port, which can be very convenient when travelling.

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.		Olympus E-520	136 mm	92 mm	68 mm	535 g	750	n	May 2008	699	ebay.com
2.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
3.		Olympus E-30	142 mm	108 mm	75 mm	701 g	750	n	Nov 2008	1,299	ebay.com
4.		Olympus E-410	130 mm	91 mm	53 mm	435 g	500	n	Mar 2007	699	ebay.com
5.		Olympus E-420	130 mm	91 mm	53 mm	440 g	500	n	Mar 2008	599	ebay.com
6.		Olympus E-450	130 mm	91 mm	53 mm	440 g	500	n	Mar 2009	499	ebay.com
7.		Olympus E-510	136 mm	92 mm	68 mm	538 g	750	n	Mar 2007	799	ebay.com
8.		Olympus E-600	130 mm	94 mm	60 mm	535 g	500	n	Aug 2009	449	ebay.com
9.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	699	ebay.com
10.		Olympus E-P1	121 mm	70 mm	36 mm	355 g	300	n	Jun 2009	799	ebay.com
11.		Olympus E-P2	121 mm	70 mm	36 mm	355 g	300	n	Nov 2009	799	ebay.com
12.		Panasonic L10	135 mm	96 mm	78 mm	556 g	450	n	Aug 2007	599	ebay.com
13.		Sony A7 IV	131 mm	96 mm	80 mm	659 g	580	Y	Oct 2021	2,499	amazon.com
14.		Sony A7R II	127 mm	96 mm	60 mm	625 g	290	Y	Jun 2015	3,199	ebay.com
15.		Sony A7R IV	129 mm	96 mm	78 mm	665 g	670	Y	Jul 2019	3,499	ebay.com
16.		Sony A7S	127 mm	94 mm	48 mm	489 g	380	Y	Apr 2014	2,499	ebay.com
17.		Sony A7S III	127 mm	97 mm	81 mm	699 g	600	Y	Jul 2020	3,499	amazon.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-520 was launched at a markedly lower price (by 77 percent) than the A7S II, 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 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. 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 tend to be more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Olympus E-520 features a Four Thirds sensor and the Sony A7S II a full frame sensor. The sensor area in the A7S II is 276 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-520 has a native 4:3 aspect ratio, while the one in the A7S II offers a 3:2 aspect.

With 12MP, the A7S II offers a higher resolution than the E-520 (10MP), but the A7S II nevertheless has larger individual pixels (pixel pitch of 8.40μm versus 4.74μm for the E-520) due to its larger sensor. Moreover, the A7S II is a much more recent model (by 7 years and 4 months) than the E-520, 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 II implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7S II 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 Olympus E-520 are 18.2 x 13.7 inches or 46.3 x 34.7 cm for good quality, 14.6 x 10.9 inches or 37.1 x 27.8 cm for very good quality, and 12.2 x 9.1 inches or 30.9 x 23.2 cm for excellent quality prints.

The Olympus E-520 has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Sony Alpha 7S II 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 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 II offers substantially better image quality than the E-520 (overall score 30 points higher). The advantage is based on 2.2 bits higher color depth, 2.9 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.		Olympus E-520	Four Thirds	10.0	3648	2736	none	21.4	10.4	548	55
2.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
3.		Olympus E-30	Four Thirds	12.2	4032	3024	none	21.3	10.4	530	55
4.		Olympus E-410	Four Thirds	10.0	3648	2736	none	21.1	10.0	494	51
5.		Olympus E-420	Four Thirds	10.0	3648	2736	none	21.5	10.4	527	56
6.		Olympus E-450	Four Thirds	10.0	3648	2736	none	21.5	10.5	512	56
7.		Olympus E-510	Four Thirds	10.0	3648	2736	none	21.2	10.0	442	52
8.		Olympus E-600	Four Thirds	12.2	4032	3024	none	21.5	10.3	541	55
9.		Olympus E-620	Four Thirds	12.2	4032	3024	none	21.3	10.3	536	55
10.		Olympus E-P1	Four Thirds	12.2	4032	3024	720/30p	21.4	10.4	536	55
11.		Olympus E-P2	Four Thirds	12.2	4032	3024	720/30p	21.5	10.4	505	56
12.		Panasonic L10	Four Thirds	10.0	3648	2736	none	21.3	10.8	429	55
13.		Sony A7 IV	Full Frame	32.7	7008	4672	4K/60p	25.4	14.7	3379	97
14.		Sony A7R II	Full Frame	42.2	7952	5304	4K/30p	26.0	13.9	3434	98
15.		Sony A7R IV	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
16.		Sony A7S	Full Frame	12.0	4240	2832	1080/60p	23.9	13.2	3702	87
17.		Sony A7S III	Full Frame	12.0	4240	2832	4K/120p	23.7	13.9	2520	86

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The A7S II indeed provides for movie recording, while the E-520 does not. The highest resolution format that the A7S II can use is 4K/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A7S II has an electronic viewfinder (2400k dots), while the E-520 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 II offers a wider field of view (100%) than the one in the E-520 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A7S II has a higher magnification (0.78x vs 0.46x), 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 Olympus E-520 and Sony A7S II 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-520	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	Y
2.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
3.		Olympus E-30	optical	Y	2.7 / 230	swivel	n	1/8000s	5.0/s	Y	Y
4.		Olympus E-410	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	n
5.		Olympus E-420	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
6.		Olympus E-450	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
7.		Olympus E-510	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	Y
8.		Olympus E-600	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
9.		Olympus E-620	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
10.		Olympus E-P1	none	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
11.		Olympus E-P2	optional	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
12.		Panasonic L10	optical	n	2.5 / 207	swivel	n	1/4000s	3.0/s	Y	n
13.		Sony A7 IV	3686	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
14.		Sony A7R II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
15.		Sony A7R IV	5760	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
16.		Sony A7S	2400	n	3.0 / 921	tilting	n	1/8000s	5.0/s	n	n
17.		Sony A7S III	9440	n	3.0 / 1440	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 difference between the cameras concerns the presence of an on-board flash. The E-520 has one, while the A7S II does not. While the built-in flash of the E-520 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 II 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-520 writes its imaging data to Compact Flash or xD Picture cards, while the A7S II uses SDXC or Memory Stick PRO Duo cards. The E-520 features dual card slots, which can be very useful in case a memory card fails. In contrast, the A7S II only has one slot.

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 E-520 and Sony Alpha 7S II 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-520	Y	- / -	-	-	-	2.0	-	-	-
2.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
3.		Olympus E-30	Y	- / -	-	-	-	2.0	-	-	-
4.		Olympus E-410	Y	- / -	-	-	-	2.0	-	-	-
5.		Olympus E-420	Y	- / -	-	-	-	2.0	-	-	-
6.		Olympus E-450	Y	- / -	-	-	-	2.0	-	-	-
7.		Olympus E-510	Y	- / -	-	-	-	2.0	-	-	-
8.		Olympus E-600	Y	- / -	-	-	-	2.0	-	-	-
9.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
10.		Olympus E-P1	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Olympus E-P2	Y	stereo / -	-	-	mini	2.0	-	-	-
12.		Panasonic L10	Y	- / -	-	-	-	2.0	-	-	-
13.		Sony A7 IV	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
14.		Sony A7R II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A7R IV	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
16.		Sony A7S	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony A7S III	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y

It is notable that the A7S II offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the E-520 does not provide wifi capability.

Both the E-520 and the A7S II have been discontinued, but can regularly be found used on ebay. The A7S II was replaced by the Sony A7S III, while the E-520 does not have a direct successor. Further information on the features and operation of the E-520 and A7S II can be found, respectively, in the Olympus E-520 Manual (free pdf) or the online Sony A7S II Manual.

Review summary

So what conclusions can be drawn? Is the Olympus E-520 better than the Sony A7S II or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Olympus E-520:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Less heavy: Is lighter (by 92g or 15 percent) and hence easier to carry around.
• Longer lasting: Can take more shots (750 versus 370) on a single battery charge.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More affordable: Was introduced into a lower priced category (77 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in May 2008).

Advantages of the Sony Alpha 7S II:

• More detail: Has more megapixels (12 vs 10MP), which boosts linear resolution by 12%.
• Better image quality: Scores substantially higher (30 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.2 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.9 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 4K/30p 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 (0.78x vs 0.46x).
• Larger screen: Has a bigger rear LCD (3.0" vs 2.7") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (1229k vs 215k 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 3.5 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.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• 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 7 years and 4 months of technical progress since the E-520 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the A7S II is the clear winner of the contest (21 : 7 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 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 Olympus E-520 and the Sony A7S II 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 says little about, for example, the shooting experience and imaging performance of the E-520 and the A7S II in practical situations. 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 why expert reviews are important. 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-520	..	87/100	..	+ +	4.5/5	4.5/5	May 2008	699	ebay.com
2.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
3.		Olympus E-30	..	..	..	71/100	4.5/5	4/5	Nov 2008	1,299	ebay.com
4.		Olympus E-410	..	86/100	..	+ +	4/5	4.5/5	Mar 2007	699	ebay.com
5.		Olympus E-420	..	85/100	..	+ +	4/5	4.5/5	Mar 2008	599	ebay.com
6.		Olympus E-450	..	..	..	..	4/5	4/5	Mar 2009	499	ebay.com
7.		Olympus E-510	..	89/100	..	+ +	3.5/5	4.5/5	Mar 2007	799	ebay.com
8.		Olympus E-600	..	..	..	..	..	4.5/5	Aug 2009	449	ebay.com
9.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	699	ebay.com
10.		Olympus E-P1	..	+	..	66/100	4/5	4.5/5	Jun 2009	799	ebay.com
11.		Olympus E-P2	3/5	+	..	69/100	4/5	4.5/5	Nov 2009	799	ebay.com
12.		Panasonic L10	..	85/100	..	+	3.5/5	4/5	Aug 2007	599	ebay.com
13.		Sony A7 IV	5/5	+ +	4.5/5	89/100	4.5/5	4.5/5	Oct 2021	2,499	amazon.com
14.		Sony A7R II	5/5	+ +	5/5	90/100	5/5	5/5	Jun 2015	3,199	ebay.com
15.		Sony A7R IV	5/5	+	4.5/5	91/100	4.5/5	5/5	Jul 2019	3,499	ebay.com
16.		Sony A7S	4/5	..	..	86/100	4.5/5	5/5	Apr 2014	2,499	ebay.com
17.		Sony A7S III	4.5/5	+ +	5/5	91/100	4.5/5	5/5	Jul 2020	3,499	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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

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Other camera comparisons

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