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Nikon D7100 versus Sony A9

The Nikon D7100 and the Sony Alpha A9 are two digital cameras that were officially introduced, respectively, in February 2013 and April 2017. The D7100 is a DSLR, while the A9 is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (D7100) and a full frame (A9) sensor. Both cameras offer a resolution of 24 megapixel. 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: Nikon D7100 vs Sony A9

An illustration of the physical size and weight of the Nikon D7100 and the Sony A9 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. You can also toggle the display to switch to a percentage comparison if you prefer that the measures are being expressed in relative terms (in this case, the camera on the left – the D7100 – represents the basis or 100 percent across all the size and weight measures).

Compare Nikon D7100 vs Sony A9
Compare D7100 versus A9 top
Compare D7100 and A9 rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A9 is notably smaller (16 percent) than the Nikon D7100. Moreover, the A9 is markedly lighter (12 percent) than the D7100. 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 Nikon Lens Catalog (D7100) and the Sony FE Lens Catalog (A9). Mirrorless cameras, such as the A9, 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 D7100 gets 950 shots out of its EN-EL15 battery, while the A9 can take 650 images on a single charge of its NP-FZ100 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. In case you want to display and compare another camera duo, just click on the right or left arrow next to the camera that you would like to inspect. Alternatively, you can also use the CAM-parator to select your camera combination among a larger number of options.

Camera Body Specifications
  Camera
Model
Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(yes/no)
Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Nikon D7100» 5.4 in 4.2 in 3.0 in 27.0 oz 950 Y Feb 2013 1,199- i Nikon D7100
Sony A9« 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i Sony A9
Canon 80D« » 5.5 in 4.1 in 3.1 in 25.8 oz 960 Y Feb 2016 1,199 i i Canon 80D
Canon 70D« » 5.5 in 4.1 in 3.1 in 26.6 oz 920 Y Jul 2013 1,199- i Canon 70D
Nikon D7500« » 5.4 in 4.1 in 2.9 in 25.4 oz 950 Y Apr 2017 1,299 i i Nikon D7500
Nikon D500« » 5.8 in 4.5 in 3.2 in 30.3 oz 1240 Y Jan 2016 1,999 i i Nikon D500
Nikon D7200« » 5.4 in 4.2 in 3.0 in 27.0 oz 1110 Y Mar 2015 1,199- i Nikon D7200
Nikon D750« » 5.6 in 4.4 in 3.1 in 26.5 oz 1230 Y Sep 2014 2,299 i i Nikon D750
Nikon D610« » 5.6 in 4.4 in 3.2 in 30.0 oz 900 Y Oct 2013 1,999 i i Nikon D610
Nikon D600« » 5.6 in 4.4 in 3.2 in 30.0 oz 900 Y Sep 2012 2,099- i Nikon D600
Nikon D7000« » 5.2 in 4.1 in 3.0 in 27.5 oz 1050 Y Sep 2010 1,499- i Nikon D7000
Olympus E-M1 II« » 5.3 in 3.6 in 2.6 in 20.2 oz 440 Y Sep 2016 1,999 i i Olympus E-M1 II
Panasonic GH5« » 5.5 in 3.9 in 3.4 in 25.6 oz 410 Y Jan 2017 1,999 i i Panasonic GH5
Sony A7 III« » 5.0 in 3.8 in 2.9 in 22.9 oz 610 Y Feb 2018 1,999 i i Sony A7 III
Sony A7R III« » 5.0 in 3.8 in 2.9 in 22.9 oz 650 Y Oct 2017 3,199 i i Sony A7R III
Sony A7 II« » 5.0 in 3.8 in 2.4 in 21.1 oz 350 Y Nov 2014 1,999- i Sony A7 II
Sony RX10« » 5.1 in 3.5 in 4.0 in 28.7 oz 420 Y Oct 2013 1,299- i Sony RX10

The price is, of course, an important factor in any camera decision. 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 D7100 was launched at a markedly lower price (by 73 percent) than the A9, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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: Nikon D7100 vs Sony A9

The size of the sensor inside a digital camera is one of the key determinants 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. 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 Nikon D7100 features an APS-C sensor and the Sony A9 a full frame sensor. The sensor area in the A9 is 131 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Nikon D7100 and Sony A9 sensor measures

Even though the A9 has a larger sensor, both cameras offer the same resolution of 24 megapixel. This implies that the A9 has a lower pixel density and larger individual pixels (with a pixel pitch of 5.94μm versus 3.91μm for the D7100), which gives it a potential advantage in terms of light gathering capacity. In addition, the A9 is much more recent (by 4 years and 1 month) than the D7100, and its sensor will have benefitted from technological advances during this time. Coming back to sensor resolution, it should be mentioned that the D7100 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

D7100 versus A9 MP

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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 A9 has a markedly higher DXO score than the D7100 (overall score 9 points higher), which will translate into better image quality. The advantage is based on 0.7 bits higher color depth, 0.4 EV of lower dynamic range, and 1.5 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
Camera
Model
Nikon D7100» APS-C 24.0 6000 40001080/60p24.213.7125683Nikon D7100
Sony A9« Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
Canon 80D« » APS-C 24.0 6000 40001080/60p23.613.2113579Canon 80D
Canon 70D« » APS-C 20.0 5472 36481080/30p22.511.692668Canon 70D
Nikon D7500« » APS-C 20.7 5568 37124K/30p24.314.0148386Nikon D7500
Nikon D500« » APS-C 20.7 5568 37124K/30p24.014.0132483Nikon D500
Nikon D7200« » APS-C 24.0 6000 40001080/60p24.514.6133387Nikon D7200
Nikon D750« » Full Frame 24.2 6016 40161080/60p24.814.5295693Nikon D750
Nikon D610« » Full Frame 24.2 6016 40161080/30p25.114.4292594Nikon D610
Nikon D600« » Full Frame 24.2 6016 40161080/30p25.114.2298094Nikon D600
Nikon D7000« » APS-C 16.1 4928 326410800/24p23.513.9116780Nikon D7000
Olympus E-M1 II« » Four Thirds 20.2 5184 38884K/30p23.712.8131280Olympus E-M1 II
Panasonic GH5« » Four Thirds 20.2 5184 38884K/60p23.913.080777Panasonic GH5
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
Sony A7R III« » Full Frame 42.2 7952 53044K/30p26.014.73523100Sony A7R III
Sony A7 II« » Full Frame 24.0 6000 40001080/60p24.913.6244990Sony A7 II
Sony RX10« » 1-inch 20.0 5472 36481080/60p22.912.647469Sony RX10

Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A9 provides a better video resolution than the D7100. It can shoot movie footage at 4K/30p, while the Nikon is limited to 1080/60p.

 

Feature comparison: Nikon D7100 vs Sony A9

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A9 has an electronic viewfinder (3686k 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 following table reports on some other key feature differences and similarities of the Nikon D7100, the Sony A9, and comparable cameras. If needed, the dpreview camera hub, for example, contains further detail on the cameras' specs.

Core Features
  Camera
Model
Viewfinder
(Type or
'000 dots)
Control
Panel
(yes/no)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(yes/no)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec)
Build-in
Flash
(yes/no)
Build-in
Image
Stab
Camera
Model
Nikon D7100»optical Y 3.2 1229 fixed n 8000 6.0 Y n Nikon D7100
Sony A9«3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
Canon 80D« »optical Y 3.0 1040 swivel Y 8000 7.0 Y n Canon 80D
Canon 70D« »optical Y 3.0 1040 swivel Y 8000 7.0 Y n Canon 70D
Nikon D7500« »optical Y 3.2 922 tilting Y 8000 8.0 Y n Nikon D7500
Nikon D500« »optical Y 3.2 2359 tilting Y 8000 10.0 n n Nikon D500
Nikon D7200« »optical Y 3.2 1229 fixed n 8000 6.0 Y n Nikon D7200
Nikon D750« »optical Y 3.2 1229 tilting n 4000 6.0 Y n Nikon D750
Nikon D610« »optical Y 3.2 921 fixed n 4000 6.0 Y n Nikon D610
Nikon D600« »optical Y 3.0 921 fixed n 4000 5.5 Y n Nikon D600
Nikon D7000« »optical Y 3.0 921 fixed n 8000 6.0 Y n Nikon D7000
Olympus E-M1 II« »2360 n 3.0 1037 swivel Y 8000 18.0 n Y Olympus E-M1 II
Panasonic GH5« »3680 n 3.2 1620 swivel Y 8000 12.0 n Y Panasonic GH5
Sony A7 III« »2359 n 3.0 922 tilting Y 8000 10.0 n Y Sony A7 III
Sony A7R III« »3686 n 3.0 1440 tilting Y 8000 10.0 n Y Sony A7R III
Sony A7 II« »2400 n 3.0 1230 tilting n 8000 5.0 n Y Sony A7 II
Sony RX10« »1440 Y 3.0 1229 tilting n 3200 10.0 Y Y Sony RX10

One difference between the cameras concerns the presence of an on-board flash. The D7100 has one, while the A9 does not. While the build-in flash of the D7100 is not very powerful, it can at times be useful as a fill-in light.

The reported shutter speed and shutter burst refer to the use of the mechanical shutter. In addition, the A9 features an electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (rolling shutter) or shooting under artificial light sources (flickering).

The D7100 writes its imaging data to SDXC cards, while the A9 uses SDXC or Memory Stick PRO Duo cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails.

Input-Output Connections
  Camera
Model
Hotshoe
Port
Internal
Microphone
Internal
Speaker
Microphone
Port
Headphone
Port
HDMI
Port
USB
Type
WiFi
Support
NFC
Support
Bluetooth
Support
Camera
Model
Nikon D7100»YstereomonoYYmini2.0---Nikon D7100
Sony A9«YstereomonoYYmicro2.0YYYSony A9
Canon 80D« »YstereomonoYYmini2.0YY-Canon 80D
Canon 70D« »YstereomonoY-mini2.0Y--Canon 70D
Nikon D7500« »YstereomonoYYmini2.0Y-YNikon D7500
Nikon D500« »YstereomonoYYmini3.0YYYNikon D500
Nikon D7200« »YstereomonoYYmini2.0YY-Nikon D7200
Nikon D750« »YstereomonoYYmini2.0Y--Nikon D750
Nikon D610« »YmonomonoYYmini2.0---Nikon D610
Nikon D600« »YmonomonoYYmini2.0---Nikon D600
Nikon D7000« »YmonomonoY-mini2.0---Nikon D7000
Olympus E-M1 II« »YstereomonoYYmicro3.0Y--Olympus E-M1 II
Panasonic GH5« »YstereomonoYYfull3.1Y-YPanasonic GH5
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
Sony A7R III« »YstereomonoYYmicro3.1YYYSony A7R III
Sony A7 II« »YstereomonoYYmicro2.0YY-Sony A7 II
Sony RX10« »YstereomonoYYmicro2.0YY-Sony RX10

The A9 is a current model that online retailers, such as amazon, will have in stock. In contrast, the D7100 has been discontinued (but it can be found pre-owned on eBay). As a replacement in the same line of cameras, the D7100 was succeeded by the Nikon D7200.

Review summary: Nikon D7100 vs Sony A9

So what is the bottom line? Is the Nikon D7100 better than the Sony A9 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

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Arguments in favor of the Nikon D7100:

  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • Brighter framing: Features an optical viewfinder for clear, lag-free composition.
  • Easier setting verification: Features an LCD display on top to control shooting parameters.
  • Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
  • Longer lasting: Can take more shots (950 versus 650) on a single battery charge.
  • Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
  • More affordable: Was introduced into a lower priced category (73 percent cheaper at launch).
  • More heavily discounted: Has been available for much longer (launched in February 2013).

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Advantages of the Sony Alpha A9:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Better image quality: Scores markedly higher (9 points) in the DXO overall evaluation.
  • Better low-light sensitivity: Can shoot in dim conditions (1.5 stops ISO advantage).
  • Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More detailed LCD: Has a higher resolution rear screen (1440k vs 1229k dots).
  • More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
  • Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
  • Faster burst: Shoots at higher frequency (20 vs 6 flaps/sec) to capture the decisive moment.
  • Less disturbing: Has an electronic shutter option for completely silent shooting.
  • More compact: Is smaller (127x96mm vs 136x107mm) and will fit more readily into a bag.
  • Less heavy: Has a lower weight (by 92g or 12 percent) and is thus easier to take along.
  • Sharper images: Has stabilization technology build-in to reduce the impact of hand-shake.
  • More legacy lens friendly: Can use many non-native lenses via adapters.
  • Easier file upload: Has wifi build in for automatic backup or image transfer to the web.
  • Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
  • Easier wireless transfer: Supports Bluetooth for image sharing without cables.
  • More modern: Reflects 4 years and 1 month of technical progress since the D7100 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the A9 is the clear winner of the contest (18 : 8 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 before making a camera decision.

D7100 08:18 A9

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains incomplete and does no justice, for example, to the way the D7100 or the A9 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 hands-on reviews by experts are important. The following table reports the overall rankings of the cameras as published by some of the major camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). You can find the full text of the reviews by clicking on the site logo in the table header.

Review Scores
  Camera
Model
cameralabs dpreview ephotozine imaging-resource photographyblog Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Nikon D7100»HiRec85/1004.5/55/54.5/5 Feb 2013 1,199- i Nikon D7100
Sony A9«HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
Canon 80D« »HiRec84/1004.5/54.5/54.5/5 Feb 2016 1,199 i i Canon 80D
Canon 70D« »HiRec83/1004.5/54.5/55/5 Jul 2013 1,199- i Canon 70D
Nikon D7500« »HiRec86/1005/54.5/54.5/5 Apr 2017 1,299 i i Nikon D7500
Nikon D500« »HiRec91/1004.5/55/55/5 Jan 2016 1,999 i i Nikon D500
Nikon D7200« »HiRec84/1004.5/54/54.5/5 Mar 2015 1,199- i Nikon D7200
Nikon D750« »HiRec90/1004.5/55/54.5/5 Sep 2014 2,299 i i Nikon D750
Nikon D610« »HiRec87/1004.5/54.5/54.5/5 Oct 2013 1,999 i i Nikon D610
Nikon D600« »HiRec87/1005/54.5/54.5/5 Sep 2012 2,099- i Nikon D600
Nikon D7000« »-80/1004.5/55/54.5/5 Sep 2010 1,499- i Nikon D7000
Olympus E-M1 II« »HiRec85/1004.5/55/54.5/5 Sep 2016 1,999 i i Olympus E-M1 II
Panasonic GH5« »HiRec85/1004.5/55/55/5 Jan 2017 1,999 i i Panasonic GH5
Sony A7 III« »HiRec89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
Sony A7R III« »HiRec90/1004.5/55/55/5 Oct 2017 3,199 i i Sony A7R III
Sony A7 II« »Rec82/1004.5/55/55/5 Nov 2014 1,999- i Sony A7 II
Sony RX10« »Rec80/1004.5/54.5/54.5/5 Oct 2013 1,299- i Sony RX10

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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

 

Other camera comparisons

Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, 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 the camera you are interested in is not available, please send me an email, and I will try to add information on that model to the database.

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