Olympus E-P1 vs Sony A900

The Olympus PEN E-P1 and the Sony Alpha A900 are two digital cameras that were revealed to the public, respectively, in June 2009 and September 2008. The E-P1 is a mirrorless interchangeable lens camera, while the A900 is a DSLR. The cameras are based on a Four Thirds (E-P1) and a full frame (A900) sensor. The Olympus has a resolution of 12.2 megapixels, whereas the Sony provides 24.4 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 A900
Mirrorless system camera		Digital single lens reflex
Micro Four Thirds lenses		Sony A mount lenses
12.2 MP – Four Thirds sensor		24.4 MP – Full Frame sensor
720/30p Video		no Video
ISO 100-6,400		ISO 200-3,200 (100 - 6,400)
No viewfinder, LCD framing		Optical viewfinder
3.0" LCD – 230k dots		3.0" LCD – 922k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
3 shutter flaps per second		5 shutter flaps per second
In-body stabilization		In-body stabilization
not weather sealed		Weathersealed body
300 shots per battery charge		880 shots per battery charge
121 x 70 x 36 mm, 355 g		156 x 117 x 82 mm, 895 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 A900? 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 Olympus E-P1 and the Sony A900 is provided in the side-by-side display below. 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.

The E-P1 can be obtained in three different colors (black, silver, white), while the A900 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 A900 is considerably larger (115 percent) than the Olympus E-P1. Moreover, the A900 is substantially heavier (152 percent) than the E-P1. It is noteworthy in this context that the A900 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. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

Concerning battery life, the E-P1 gets 300 shots out of its Olympus BLS-1 battery, while the A900 can take 880 images on a single charge of its Sony NP-FM500H power pack.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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-P1	121 mm	70 mm	36 mm	355 g	300	n	Jun 2009	EUR 699	ebay.com
2.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	EUR 2 799	ebay.com
3.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	EUR 3 299	ebay.com
4.		Olympus E-520	136 mm	92 mm	68 mm	535 g	750	n	May 2008	EUR 599	ebay.com
5.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	EUR 599	ebay.com
6.		Olympus E-M10	119 mm	82 mm	46 mm	396 g	320	n	Jan 2014	EUR 599	ebay.com
7.		Olympus E-P2	121 mm	70 mm	36 mm	355 g	300	n	Nov 2009	EUR 699	ebay.com
8.		Olympus E-P3	122 mm	69 mm	34 mm	369 g	330	n	Jun 2011	EUR 699	ebay.com
9.		Olympus E-PL1	115 mm	72 mm	42 mm	334 g	290	n	Feb 2010	EUR 599	ebay.com
10.		Olympus E-PL2	114 mm	72 mm	42 mm	362 g	280	n	Jan 2011	EUR 599	ebay.com
11.		Olympus E-PL3	110 mm	64 mm	37 mm	313 g	300	n	Jun 2011	EUR 549	ebay.com
12.		Panasonic GF1	119 mm	71 mm	36 mm	385 g	380	n	Sep 2009	EUR 649	ebay.com
13.		Panasonic GH1	124 mm	90 mm	45 mm	385 g	300	n	Mar 2009	EUR 799	ebay.com
14.		Panasonic S1	149 mm	110 mm	97 mm	1017 g	400	Y	Feb 2019	EUR 2 499	ebay.com
15.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	EUR 2 799	ebay.com
16.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	EUR 3 599	ebay.com
17.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	EUR 1 999	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 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 73 percent) than the A900, 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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. 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-P1 features a Four Thirds sensor and the Sony A900 a full frame sensor. The sensor area in the A900 is 283 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 A900 offers a 3:2 aspect.

With 24.4MP, the A900 offers a higher resolution than the E-P1 (12.2MP), but the A900 nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 4.29μm for the E-P1) due to its larger sensor. However, the E-P1 is a somewhat more recent model (by 9 months) than the A900, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units.

The resolution advantage of the Sony A900 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A900 for good quality output (200 dots per inch) amounts to 30.2 x 20.2 inches or 76.8 x 51.2 cm, for very good quality (250 dpi) 24.2 x 16.1 inches or 61.4 x 41 cm, and for excellent quality (300 dpi) 20.2 x 13.4 inches or 51.2 x 34.1 cm. The corresponding values for the Olympus E-P1 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 Olympus PEN E-P1 has a native sensitivity range from ISO 100 to ISO 6400. The corresponding ISO settings for the Sony Alpha A900 are ISO 200 to ISO 3200, with the possibility to increase the ISO range to 100-6400.

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.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. This service determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). Of the two cameras under consideration, the A900 offers substantially better image quality than the E-P1 (overall score 24 points higher). The advantage is based on 2.3 bits higher color depth, 1.9 EV in additional dynamic range, and 1.4 stops in additional low light sensitivity. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-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 A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
3.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
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-M10	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.3	884	72
7.		Olympus E-P2	Four Thirds	12.2	4032	3024	720/30p	21.5	10.4	505	56
8.		Olympus E-P3	Four Thirds	12.2	4032	3024	1080/60i	20.8	10.1	536	51
9.		Olympus E-PL1	Four Thirds	12.2	4032	3024	720/30p	21.5	10.1	487	54
10.		Olympus E-PL2	Four Thirds	12.2	4032	3024	720/30p	21.4	10.2	573	55
11.		Olympus E-PL3	Four Thirds	12.2	4032	3024	1080/60i	20.9	10.3	499	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.		Panasonic S1	Full Frame	24.0	6000	4000	4K/60p	25.2	14.5	3333	95
15.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
16.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
17.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79

Many modern cameras cannot only take still pictures, but also record videos. The E-P1 indeed provides movie recording capabilities, while the A900 does not. The highest resolution format that the E-P1 can use is 720/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A900 has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the E-P1 relies on live view and the rear LCD for framing. The table below summarizes some of the other core capabilities of the Olympus E-P1 and Sony A900 in connection with corresponding information for a sample of similar 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-P1	none	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
2.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
3.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/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-M10	1440	n	3.0 / 1037	tilting	Y	1/4000s	8.0/s	Y	Y
7.		Olympus E-P2	optional	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
8.		Olympus E-P3	optional	n	3.0 / 614	fixed	Y	1/4000s	3.0/s	Y	Y
9.		Olympus E-PL1	optional	n	2.7 / 230	fixed	n	1/2000s	3.0/s	Y	Y
10.		Olympus E-PL2	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	Y
11.		Olympus E-PL3	optional	n	3.0 / 460	tilting	n	1/4000s	5.5/s	n	Y
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.		Panasonic S1	5760	Y	3.2 / 2100	full-flex	Y	1/8000s	9.0/s	n	Y
15.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
16.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
17.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the A900, but is missing on the E-P1 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The E-P1 writes its imaging data to SDHC cards, while the A900 uses Compact Flash or Memory Stick PRO Duo cards. The A900 features dual card slots, which can be very useful in case a memory card fails. In contrast, the E-P1 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 PEN E-P1 and Sony Alpha A900 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 A900	Y	- / -	-	-	mini	2.0	-	-	-
3.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
4.		Olympus E-520	Y	- / -	-	-	-	2.0	-	-	-
5.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
6.		Olympus E-M10	Y	stereo / mono	-	-	micro	2.0	Y	-	-
7.		Olympus E-P2	Y	stereo / -	-	-	mini	2.0	-	-	-
8.		Olympus E-P3	Y	stereo / -	-	-	mini	2.0	-	-	-
9.		Olympus E-PL1	Y	stereo / -	-	-	mini	2.0	-	-	-
10.		Olympus E-PL2	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Olympus E-PL3	Y	stereo / -	-	-	mini	2.0	-	-	-
12.		Panasonic GF1	Y	mono / mono	-	-	mini	2.0	-	-	-
13.		Panasonic GH1	Y	stereo / -	Y	-	mini	2.0	-	-	-
14.		Panasonic S1	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
15.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
16.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
17.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-

Studio photographers will appreciate that the Sony A900 (unlike the E-P1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the E-P1 and the A900 have been discontinued, but can regularly be found used on ebay. The A900 was replaced by the Sony A99, while the E-P1 was followed by the Olympus E-P2. Further information on the features and operation of the E-P1 and A900 can be found, respectively, in the Olympus E-P1 Manual (free pdf) or the online Sony A900 Manual.

Review summary

So how do things add up? Is there a clear favorite between the Olympus E-P1 and the Sony A900? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer the Olympus PEN E-P1:

• Broader imaging potential: Can record not only still images but also 720/30p movies.
• More compact: Is smaller (121x70mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 540g or 60 percent) and hence easier to carry around.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• More affordable: Was introduced into a lower priced category (73 percent cheaper at launch).
• More modern: Is somewhat more recent (announced 9 months after the A900).

Advantages of the Sony Alpha A900:

• More detail: Has more megapixels (24.4 vs 12.2MP), which boosts linear resolution by 44%.
• Better image quality: Scores substantially higher (24 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.3 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1.9 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (1.4 stops ISO advantage).
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• More detailed LCD: Has a higher resolution rear screen (922k vs 230k dots).
• 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.
• Longer lasting: Gets more shots (880 versus 300) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More heavily discounted: Has been on the market for longer (launched in September 2008).

If the count of individual advantages (bullet points above) is taken as a guide, the A900 is the clear winner of the contest (15 : 6 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 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 Olympus E-P1 and the Sony A900 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best DSLR 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 remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the E-P1 or the A900. 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 following table reports the overall ratings of the cameras as published by some of the major 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	Street Price
1.		Olympus E-P1	..	+	..	66/100	4/5	4.5/5	Jun 2009	EUR 699	ebay.com
2.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	EUR 2 799	ebay.com
3.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	EUR 3 299	ebay.com
4.		Olympus E-520	..	87/100	..	+ +	4.5/5	4.5/5	May 2008	EUR 599	ebay.com
5.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	EUR 599	ebay.com
6.		Olympus E-M10	4/5	..	..	80/100	5/5	5/5	Jan 2014	EUR 599	ebay.com
7.		Olympus E-P2	3/5	+	..	69/100	4/5	4.5/5	Nov 2009	EUR 699	ebay.com
8.		Olympus E-P3	..	83/100	..	74/100	4.5/5	4.5/5	Jun 2011	EUR 699	ebay.com
9.		Olympus E-PL1	..	86/100	..	69/100	4/5	4.5/5	Feb 2010	EUR 599	ebay.com
10.		Olympus E-PL2	3/5	83/100	..	71/100	4.5/5	4.5/5	Jan 2011	EUR 599	ebay.com
11.		Olympus E-PL3	3/5	+ +	..	72/100	4.5/5	4/5	Jun 2011	EUR 549	ebay.com
12.		Panasonic GF1	..	85/100	..	69/100	4.5/5	4.5/5	Sep 2009	EUR 649	ebay.com
13.		Panasonic GH1	..	+ +	..	72/100	4.5/5	4.5/5	Mar 2009	EUR 799	ebay.com
14.		Panasonic S1	4.5/5	+ +	4.5/5	88/100	4.5/5	4/5	Feb 2019	EUR 2 499	ebay.com
15.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	EUR 2 799	ebay.com
16.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	EUR 3 599	ebay.com
17.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	EUR 1 999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. 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

Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just use the search menu below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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