Sony A7 versus Olympus E-M1
The Sony Alpha A7 and the Olympus OM-D E-M1 are two enthusiast cameras that were revealed to the public, respectively, in October 2013 and September 2013. Both the A7 and the E-M1 are mirrorless interchangeable lens cameras that are based on a full frame (A7) and a Four Thirds (E-M1) sensor. The Sony has a resolution of 24 megapixel, whereas the Olympus provides 15.9 MP. Read on to find out how these two cameras compare with respect to their size, their sensors, their features, and their reception by expert reviewers.
Body comparison: Sony A7 vs Olympus E-M1
An illustration of the physical size and weight of the Sony A7 and the Olympus E-M1 is provided in the side-by-side display below. Three consecutive perspectives from the front, the top, and the back are presented. All size dimensions are rounded to the nearest millimeter. If you prefer, you can also use the toggle button to switch to a comparison in percentage terms (in this case, the camera on the left side – the A7 – represents the basis for the calculations across all the size and weight measures).
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Olympus E-M1 is somewhat larger (2 percent) than the Sony A7. Moreover, the E-M1 is markedly heavier (5 percent) than the A7. In this context, it is worth noting that both cameras are splash and dust-proof and can, hence, be used in inclement weather conditions or harsh environments.
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 find an overview of optics for the two cameras in the Sony FE Lens Catalog (A7) and the Micro Four Thirds Lens Catalog (E-M1). 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.
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, just select a new right or left comparator from among the camera models in the table. Alternatively, you can also move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.
|Camera Body Specifications
|Sony A7 (⇒ rgt)||127 mm||94 mm||48 mm||474 g||340||YES||2013||1,699||discont.||check|
|Olympus E-M1 (⇒ lft)||130 mm||94 mm||63 mm||497 g||350||YES||2013||1,399||discont.||check|
|Nikon D610 (⇒ lft | rgt)||141 mm||113 mm||82 mm||850 g||900||YES||2013||1,999||latest||check|
|Olympus E-M1 II (⇒ lft | rgt)||134 mm||91 mm||67 mm||574 g||440||YES||2016||1,999||latest||check|
|Olympus E-M5 II (⇒ lft | rgt)||124 mm||85 mm||45 mm||469 g||310||YES||2015||1,099||latest||check|
|Olympus E-M10 (⇒ lft | rgt)||119 mm||82 mm||46 mm||396 g||320||no||2014||699||discont.||check|
|Olympus E-P5 (⇒ lft | rgt)||122 mm||69 mm||37 mm||420 g||330||no||2013||999||discont.||check|
|Olympus E-M5 (⇒ lft | rgt)||122 mm||89 mm||43 mm||425 g||360||YES||2012||1,299||discont.||check|
|Panasonic GH4 (⇒ lft | rgt)||133 mm||93 mm||84 mm||560 g||500||YES||2014||1,499||discont.||check|
|Sony A6300 (⇒ lft | rgt)||120 mm||67 mm||49 mm||404 g||400||YES||2016||999||discont.||check|
|Sony A6500 (⇒ lft | rgt)||120 mm||67 mm||53 mm||453 g||350||YES||2016||1,399||latest||check|
|Sony A7 II (⇒ lft | rgt)||127 mm||96 mm||60 mm||599 g||350||YES||2014||1,999||discont.||check|
|Sony A7S (⇒ lft | rgt)||127 mm||94 mm||48 mm||489 g||380||YES||2014||2,499||discont.||check|
|Sony A5100 (⇒ lft | rgt)||110 mm||63 mm||36 mm||283 g||400||no||2014||549||latest||check|
|Sony A7R (⇒ lft | rgt)||127 mm||94 mm||48 mm||465 g||340||YES||2013||2,299||discont.||check|
|Sony RX1R (⇒ lft | rgt)||113 mm||65 mm||70 mm||482 g||270||no||2013||2,799||discont.||check|
|Sony RX1 (⇒ lft | rgt)||113 mm||65 mm||70 mm||482 g||270||no||2012||2,799||discont.||check|
The price is, of course, an important factor in any camera decision. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The E-M1 was launched at a somewhat lower price (by 18 percent) than the A7, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.
Sensor comparison: Sony A7 vs Olympus E-M1
The imaging sensor is at the core of digital cameras and its size is one of the main determining factors of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color depth than smaller pixel-units in a sensor of the same technological generation. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to 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 Sony A7 features a full frame sensor and the Olympus E-M1 a Four Thirds sensor. The sensor area in the E-M1 is 74 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 2.0. The sensor in the A7 has a native 3:2 aspect ratio, while the one in the E-M1 offers a 4:3 aspect.
With 24MP, the A7 offers a higher resolution than the E-M1 (15.9MP), but the A7 nevertheless has larger individual pixels (pixel pitch of 5.97μm versus 3.76μm for the E-M1) due to its larger sensor. It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation. Coming back to sensor resolution, it should be mentioned that the E-M1 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
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 A7 provides substantially higher image quality than the E-M1, with an overall score that is 17 points higher. This advantage is based on 1.8 bits higher color depth, 1.5 EV in additional dynamic range, and 1.6 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.
|Sony A7 (⇒ rgt)||Full Frame||24.0||6000||4000||1080/60p||24.8||14.2||2248||90|
|Olympus E-M1 (⇒ lft)||Four Thirds||15.9||4608||3456||1080/30p||23.0||12.7||757||73|
|Nikon D610 (⇒ lft | rgt)||Full Frame||24.2||6016||4016||1080/30p||25.1||14.4||2925||94|
|Olympus E-M1 II (⇒ lft | rgt)||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|Olympus E-M5 II (⇒ lft | rgt)||Four Thirds||15.9||4608||3456||1080/60p||23.0||12.5||842||73|
|Olympus E-M10 (⇒ lft | rgt)||Four Thirds||15.9||4608||3456||1080/30p||22.8||12.3||884||72|
|Olympus E-P5 (⇒ lft | rgt)||Four Thirds||15.9||4608||3456||1080/30p||22.8||12.4||895||72|
|Olympus E-M5 (⇒ lft | rgt)||Four Thirds||15.9||4608||3456||1080/60i||22.8||12.3||826||71|
|Panasonic GH4 (⇒ lft | rgt)||Four Thirds||15.9||4608||3456||4K/30p||23.2||12.8||791||74|
|Sony A6300 (⇒ lft | rgt)||APS-C||24.0||6000||4000||4K/30p||24.4||13.7||1437||85|
|Sony A6500 (⇒ lft | rgt)||APS-C||24.0||6000||4000||4K/30p||24.5||13.7||1405||85|
|Sony A7 II (⇒ lft | rgt)||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|Sony A7S (⇒ lft | rgt)||Full Frame||12.0||4240||2832||1080/60p||23.9||13.2||3702||87|
|Sony A5100 (⇒ lft | rgt)||APS-C||24.0||6000||4000||1080/60p||23.8||12.7||1347||80|
|Sony A7R (⇒ lft | rgt)||Full Frame||36.2||7360||4912||1080/60p||25.6||14.1||2746||95|
|Sony RX1R (⇒ lft | rgt)||Full Frame||24.0||6000||4000||1080/60p||25.0||13.6||2537||91|
|Sony RX1 (⇒ lft | rgt)||Full Frame||24.0||6000||4000||1080/60p||25.1||14.3||2534||93|
Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A7 provides a higher frame rate than the E-M1. It can shoot video footage at 1080/60p, while the Olympus is limited to 1080/30p.
Feature comparison: Sony A7 vs Olympus E-M1
Beyond body and sensor, cameras can and do differ across a range of features. The two cameras under consideration are similar with respect to both having an electronic viewfinder. However, the one in the A7 offers a slightly higher resolution than the one in the E-M1 (2400k vs 2360k dots). The table below summarizes some of the other core capabilities of the Sony A7 and Olympus E-M1 in connection with corresponding information for a sample of similar cameras. If needed, the dpreview camera hub, for example, contains further detail on the cameras' specs.
|Sony A7 (⇒ rgt)||2400||no||3.0||1230||tilting||no||8000||5.0||no||no|
|Olympus E-M1 (⇒ lft)||2360||no||3.0||1037||tilting||YES||8000||10.0||no||YES|
|Nikon D610 (⇒ lft | rgt)||optical||YES||3.2||921||fixed||no||4000||6.0||12||no|
|Olympus E-M1 II (⇒ lft | rgt)||2360||no||3.0||1037||swivel||YES||8000||18.0||no||YES|
|Olympus E-M5 II (⇒ lft | rgt)||2360||no||3.0||1037||swivel||YES||8000||10.0||no||YES|
|Olympus E-M10 (⇒ lft | rgt)||1440||no||3.0||1037||tilting||YES||4000||8.0||5.8||YES|
|Olympus E-P5 (⇒ lft | rgt)||no||no||3.0||1037||tilting||YES||8000||9.0||7||YES|
|Olympus E-M5 (⇒ lft | rgt)||1440||no||3.0||610||tilting||YES||4000||9.0||no||YES|
|Panasonic GH4 (⇒ lft | rgt)||2359||no||3.0||1036||swivel||YES||8000||12.0||17||no|
|Sony A6300 (⇒ lft | rgt)||2300||no||3.0||922||tilting||no||4000||11.0||6||no|
|Sony A6500 (⇒ lft | rgt)||2300||no||3.0||922||tilting||YES||4000||11.0||6||YES|
|Sony A7 II (⇒ lft | rgt)||2400||no||3.0||1230||tilting||no||8000||5.0||no||YES|
|Sony A7S (⇒ lft | rgt)||2400||no||3.0||921||tilting||no||8000||5.0||no||no|
|Sony A5100 (⇒ lft | rgt)||no||no||3.0||922||tilting||YES||4000||6.0||4||no|
|Sony A7R (⇒ lft | rgt)||2400||no||3.0||1230||tilting||no||8000||4.0||no||no|
|Sony RX1R (⇒ lft | rgt)||no||no||3.0||1229||fixed||no||4000||5.0||6||no|
|Sony RX1 (⇒ lft | rgt)||no||no||3.0||1229||fixed||no||4000||5.0||6||no|
Both the A7 and the E-M1 have been discontinued, but can regularly be found used on eBay. The E-M1 was replaced by the Olympus E-M1 II, while the A7 was followed by the Sony A7 II.
Review summary: Sony A7 vs Olympus E-M1
So how do things add up? Is there a clear favorite between the Sony A7 and the Olympus E-M1? A synthesis of the relative strong points of each of the models is listed below.
Advantages of the Sony Alpha A7:
- More detail: Offers more megapixels (24 vs 15.9MP) with a 25% higher linear resolution.
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better image quality: Scores substantially higher (17 points) in the DXO overall assessment.
- Richer colors: Generates images with noticeably better colors (1.8 bits more color depth).
- More dynamic range: Captures a larger spectrum of light and dark details (1.5 EV of extra DR).
- Better low-light sensitivity: Requires less light for good images (1.6 stops ISO advantage).
- Better video: Provides higher movie framerates (1080/60p versus 1080/30p).
- More detailed LCD: Has a higher resolution rear screen (1230k vs 1037k dots).
Reasons to prefer the Olympus OM-D E-M1:
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- Faster burst: Shoots at higher frequency (10 vs 5 flaps/sec) to capture the decisive moment.
- Sharper images: Has stabilization technology build-in to reduce the impact of hand-shake.
- More affordable: Was released into a lower priced segment (18 percent cheaper at launch).
If the count of relative strengths (bullet points above) is taken as a measure, the A7 emerges as the winner of the contest (8 : 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.
In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the A7 and the E-M1 in practical situations. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased. This is where reviews by experts come in. The following table reports the overall rankings of the cameras as published by some of the major camera review sites. The detailed reviews can be accessed, respectively, on the websites of cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.
|Sony A7 (⇒ rgt)||HiRec||80/100 Silver||5/5||4.5/5||5/5||2013||1,699||discont.||check|
|Olympus E-M1 (⇒ lft)||HiRec||84/100 Gold||4.5/5||4.5/5||4.5/5||2013||1,399||discont.||check|
|Nikon D610 (⇒ lft | rgt)||HiRec||87/100 Gold||4.5/5||4.5/5||4.5/5||2013||1,999||latest||check|
|Olympus E-M1 II (⇒ lft | rgt)||HiRec||85/100 Gold||4.5/5||5/5||4.5/5||2016||1,999||latest||check|
|Olympus E-M5 II (⇒ lft | rgt)||HiRec||81/100 Silver||5/5||4.5/5||5/5||2015||1,099||latest||check|
|Olympus E-M10 (⇒ lft | rgt)||-||80/100 Gold||5/5||4.5/5||5/5||2014||699||discont.||check|
|Olympus E-P5 (⇒ lft | rgt)||HiRec||78/100 Silver||4.5/5||4.5/5||5/5||2013||999||discont.||check|
|Olympus E-M5 (⇒ lft | rgt)||HiRec||80/100 Gold||4.5/5||5/5||5/5||2012||1,299||discont.||check|
|Panasonic GH4 (⇒ lft | rgt)||HiRec||85/100 Gold||5/5||5/5||5/5||2014||1,499||discont.||check|
|Sony A6300 (⇒ lft | rgt)||Rec||85/100 Gold||5/5||5/5||5/5||2016||999||discont.||check|
|Sony A6500 (⇒ lft | rgt)||HiRec||85/100 Silver||4.5/5||5/5||4.5/5||2016||1,399||latest||check|
|Sony A7 II (⇒ lft | rgt)||Rec||82/100 Silver||4.5/5||5/5||5/5||2014||1,999||discont.||check|
|Sony A7S (⇒ lft | rgt)||-||86/100 Gold||4.5/5||4.5/5||5/5||2014||2,499||discont.||check|
|Sony A5100 (⇒ lft | rgt)||Rec||-||4.5/5||4.5/5||5/5||2014||549||latest||check|
|Sony A7R (⇒ lft | rgt)||HiRec||82/100 Gold||4.5/5||5/5||5/5||2013||2,299||discont.||check|
|Sony RX1R (⇒ lft | rgt)||-||-||4/5||reviewed||4.5/5||2013||2,799||discont.||check|
|Sony RX1 (⇒ lft | rgt)||-||79/100 Gold||4/5||4.5/5||4.5/5||2012||2,799||discont.||check|
The above review scores should be interpreted 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 comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.
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