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Olympus E-M1 versus Nikon D7100

The Olympus OM-D E-M1 and the Nikon D7100 are two enthusiast cameras that were announced, respectively, in September 2013 and February 2013. The E-M1 is a mirrorless interchangeable lens camera, while the D7100 is a DSLR. The cameras are based on a Four Thirds (E-M1) and an APS-C sensor. The Olympus has a resolution of 15.9 megapixel, whereas the Nikon provides 24 MP.

Body comparison

An illustration of the physical size and weight of the Olympus E-M1 and the Nikon D7100 is provided in the side-by-side display below. 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. 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 – the E-M1 – represents 100 percent across all the size and weight measures).

Olympus E-M1 vs Nikon D7100 front
E-M1 versus D7100 top view
E-M1 and D7100 rear side
Body view (E-M1 on the left)

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Nikon D7100 is notably larger (19 percent) than the Olympus E-M1. Moreover, the D7100 is substantially heavier (54 percent) than the E-M1. 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 Micro Four Thirds Lens Catalog (E-M1) and the Nikon Lens Catalog (D7100). Mirrorless cameras, such as the Olympus E-M1, have moreover the advantage that they have a relatively short flange to focal plane distance and can thus use many lenses from other systems 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 comparisons there.

Camera Body Specifications
Camera Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(y/n)
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Olympus E-M1 (⇒ rgt) 130 mm 94 mm 63 mm 497 g 350 YES 2013 1,399discont. check
Nikon D7100 (⇒ lft) 136 mm 107 mm 76 mm 765 g 950 YES 2013 1,199discont. check
Canon 70D (⇒ lft | rgt) 139 mm 104 mm 79 mm 755 g 920 YES 2013 1,199discont. check
Nikon D7500 (⇒ lft | rgt) 136 mm 104 mm 73 mm 720 g 950 YES 2017 1,299 latest check
Nikon D7200 (⇒ lft | rgt) 136 mm 107 mm 76 mm 765 g 1110 YES 2015 1,199discont. check
Nikon D3300 (⇒ lft | rgt) 124 mm 98 mm 76 mm 430 g 700 no 2014 499discont. check
Nikon D7000 (⇒ lft | rgt) 132 mm 105 mm 77 mm 780 g 1050 YES 2010 1,499discont. check
Olympus E-M1 II (⇒ lft | rgt) 134 mm 91 mm 67 mm 574 g 440 YES 2016 1,999 latest check
Olympus PEN-F (⇒ lft | rgt) 125 mm 72 mm 37 mm 427 g 330 no 2016 1,199 latest check
Olympus E-M10 II (⇒ lft | rgt) 120 mm 83 mm 47 mm 390 g 320 no 2015 799discont. 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 699discont. check
Olympus E-P5 (⇒ lft | rgt) 122 mm 69 mm 37 mm 420 g 330 no 2013 999discont. check
Olympus E-M5 (⇒ lft | rgt) 122 mm 89 mm 43 mm 425 g .. YES 2012 1,299discont. check
Panasonic G85 (⇒ lft | rgt) 128 mm 89 mm 74 mm 505 g 330 YES 2016 899 latest check
Panasonic GH4 (⇒ lft | rgt) 133 mm 93 mm 84 mm 560 g 500 YES 2014 1,499discont. check
Panasonic GH3 (⇒ lft | rgt) 133 mm 93 mm 82 mm 550 g 540 YES 2012 1,299discont. check

The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The D7100 was launched at a somewhat lower price (by 14 percent) than the E-M1, 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

The size of the sensor inside a digital camera is one of the key determinants 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Olympus E-M1 features a Four Thirds sensor and the Nikon D7100 an APS-C sensor. The sensor area in the D7100 is 63 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.5. The sensor in the E-M1 has a native 4:3 aspect ratio, while the one in the D7100 offers a 3:2 aspect.

Olympus E-M1 and Nikon D7100 sensor measures
Sensor size
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Sensor size

With 24MP, the D7100 offers a higher resolution than the E-M1 (15.9MP), but the D7100 nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 3.76μm for the E-M1) due to its larger sensor. However, the E-M1 is a somewhat more recent model (by 6 months) than the D7100, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

E-M1 versus D7100 MP
Sensor resolution
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Sensor resolution

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 D7100 has a markedly higher DXO score than the E-M1 (overall score 10 points higher), which will translate into better image quality. The advantage is based on 1.2 bits higher color depth, 1 EV in additional dynamic range, and 0.7 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 Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Olympus E-M1 (⇒ rgt) Four Thirds 15.9 4608 3456 1080/30p 23.0 12.7 757 73
Nikon D7100 (⇒ lft) APS-C 24.0 6000 4000 1080/60p 24.2 13.7 1256 83
Canon 70D (⇒ lft | rgt) APS-C 20.0 5472 3648 1080/30p 22.5 11.6 926 68
Nikon D7500 (⇒ lft | rgt) APS-C 20.7 5568 3712 4K/30p 24.8 13.9 1192 86
Nikon D7200 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24.5 14.6 1333 87
Nikon D3300 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24.3 12.8 1385 82
Nikon D7000 (⇒ lft | rgt) APS-C 16.1 4928 3264 10800/24p 23.5 13.9 1167 80
Olympus E-M1 II (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/30p 23.7 12.8 1312 80
Olympus PEN-F (⇒ lft | rgt) Four Thirds 20.2 5184 3888 1080/60p 23.1 12.4 894 74
Olympus E-M10 II (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/60p 23.1 12.5 842 73
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 G85 (⇒ lft | rgt) Four Thirds 15.8 4592 3448 4K/30p 22.8 12.5 656 71
Panasonic GH4 (⇒ lft | rgt) Four Thirds 15.9 4608 3456 4K/30p 23.2 12.8 791 74
Panasonic GH3 (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/60p 22.7 12.4 812 71

Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the D7100 provides a faster frame rate than the E-M1. It can shoot movie footage at 1080/60p, while the Olympus is limited to 1080/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the E-M1 has an electronic viewfinder (2360k dots), while the D7100 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 adjacent table lists some of the other core features of the Olympus E-M1 and Nikon D7100 along with similar information for a selection of comparators. If needed, the dpreview camera hub, for example, contains further detail on the cameras' specs.

Core Features
Camera Viewfinder
(Type or
'000 dots)
Control
Panel
(Y/n)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(Y/n)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec))
Build-in
Flash
(GN)
Build-in
Image
Stab
Olympus E-M1 (⇒ rgt) 2360 no 3.0 1037 tilting YES 8000 10.0 no YES
Nikon D7100 (⇒ lft) optical YES 3.2 1229 fixed no 8000 6.0 12 no
Canon 70D (⇒ lft | rgt) optical YES 3.0 1040 swivel YES 8000 7.0 12 no
Nikon D7500 (⇒ lft | rgt) optical YES 3.2 922 tilting YES 8000 8.0 12 no
Nikon D7200 (⇒ lft | rgt) optical YES 3.2 1229 fixed no 8000 6.0 12 no
Nikon D3300 (⇒ lft | rgt) optical no 3.0 921 fixed no 4000 5.0 12 no
Nikon D7000 (⇒ lft | rgt) optical YES 3.0 921 fixed no 8000 6.0 12 no
Olympus E-M1 II (⇒ lft | rgt) 2360 no 3.0 1037 swivel YES 8000 18.0 no YES
Olympus PEN-F (⇒ lft | rgt) 2360 no 3.0 1037 swivel YES 8000 10.0 no YES
Olympus E-M10 II (⇒ lft | rgt) 2360 no 3.0 1040 tilting YES 4000 8.0 5.8 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 G85 (⇒ lft | rgt) 2360 no 3.0 1040 swivel YES 4000 9.0 6.2 YES
Panasonic GH4 (⇒ lft | rgt) 2359 no 3.0 1036 swivel YES 8000 12.0 17 no
Panasonic GH3 (⇒ lft | rgt) 1746 no 3.0 614 swivel YES 4000 6.0 12 no

Both the E-M1 and the D7100 have been discontinued, but can regularly be found used on ebay. The D7100 was replaced by the Nikon D7200, while the E-M1 was followed by the Olympus E-M1 II.

Summary

So what is the bottom line? Is there a clear favorite between the Olympus E-M1 and the Olympus E-M1? A synthesis of the relative strong points of each of the models is listed below.


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Reasons to prefer the Olympus OM-D E-M1:

  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
  • Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
  • Faster burst: Shoots at higher frequency (10 vs 6 flaps/sec) to capture the decisive moment.
  • More compact: Is smaller (130x94mm vs 136x107mm) and thus needs less room in the bag.
  • Less heavy: Is lighter (by 268g or 35 percent) and hence easier to carry around.
  • More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
  • Sharper images: Has hand-shake reducing image stabilization build-in.
  • More modern: Is somewhat more recent (announced 6 months after the D7100).

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Arguments in favor of the Nikon D7100:

  • More detail: Has more megapixels (24 vs 15.9MP), which boosts linear resolution by 25%.
  • Better image quality: Scores markedly higher (10 points) in the DXO overall evaluation.
  • Richer colors: Generates noticeably more natural colors (1.2 bits more color depth).
  • More dynamic range: Captures a broader range of light and dark details (1 EV of extra DR).
  • Better low-light sensitivity: Can shoot in dim conditions (0.7 stops ISO advantage).
  • Better video: Provides higher movie framerates (1080/60p vs 1080/30p).
  • Brighter framing: Features an optical viewfinder for clear, lag-free composition.
  • Easier setting verification: Has a control panel on top to check shooting parameters.
  • Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
  • More detailed LCD: Has a higher resolution rear screen (1229k vs 1037k dots).
  • Longer lasting: Gets more shots (950 versus 350) out of a single battery charge.
  • Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
  • More affordable: Was released into a lower priced segment (14 percent cheaper at launch).
  • More heavily discounted: Has been on the market for longer (launched in February 2013).

If the count of individual advantages (bullet points above) is taken as a guide, the D7100 is the clear winner of the contest (14 : 9 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs.

E-M1 09:14 D7100

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the E-M1 or the D7100 handle or perform in practice. 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 why expert reviews are important. The table below summarizes the assessments of some of the best known camera review sites. The full reviews are available, respectively, at cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.

Review scores
Camera camera
labs
dp
review
ephoto
zine
imaging
resource
photography
blog
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Olympus E-M1 (⇒ rgt) HiRec 84/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,399discont. check
Nikon D7100 (⇒ lft) HiRec 85/100 Gold 4.5/5 5/5 4.5/5 2013 1,199discont. check
Canon 70D (⇒ lft | rgt) HiRec 83/100 Gold 4.5/5 4.5/5 5/5 2013 1,199discont. check
Nikon D7500 (⇒ lft | rgt) HiRec 86/100 Silver 5/5 4.5/5 4.5/5 2017 1,299 latest check
Nikon D7200 (⇒ lft | rgt) HiRec 84/100 Silver 4.5/5 4/5 4.5/5 2015 1,199discont. check
Nikon D3300 (⇒ lft | rgt) Rec 77/100 Silver 4.5/5 4.5/5 4.5/5 2014 499discont. check
Nikon D7000 (⇒ lft | rgt) - 80/100 Silver 4.5/5 5/5 4.5/5 2010 1,499discont. 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 PEN-F (⇒ lft | rgt) - 82/100 Silver 4.5/5 4.5/5 5/5 2016 1,199 latest check
Olympus E-M10 II (⇒ lft | rgt) HiRec 80/100 Silver 5/5 5/5 5/5 2015 799discont. 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 699discont. check
Olympus E-P5 (⇒ lft | rgt) HiRec 78/100 Silver 4.5/5 4.5/5 5/5 2013 999discont. check
Olympus E-M5 (⇒ lft | rgt) HiRec 80/100 Gold 4.5/5 5/5 5/5 2012 1,299discont. check
Panasonic G85 (⇒ lft | rgt) HiRec 84/100 Gold 5/5 4.5/5 4.5/5 2016 899 latest check
Panasonic GH4 (⇒ lft | rgt) HiRec 85/100 Gold 5/5 5/5 5/5 2014 1,499discont. check
Panasonic GH3 (⇒ lft | rgt) HiRec 79/100 Gold 4.5/5 5/5 4.5/5 2012 1,299discont. check

Care should be taken when interpreting the review scores above, though. The ratings are only valid when refering to cameras in the same category and of the same age. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, 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.

Other comparisons

In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting. If you cannot find the camera you are interested in, kindly get in touch, and I will try to add information on that model to the database.

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