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Nikon D7100 versus Sony A9

The Nikon D7100 and the Sony Alpha A9 are two digital cameras that were announced, 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

The physical size and weight of the Nikon D7100 and the Sony A9 are illustrated 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 size dimensions are rounded to the nearest millimeter. You can also use the toggle button 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 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 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 D3300« » 4.9 in 3.9 in 3.0 in 15.2 oz 700 n Jan 2014 499- i Nikon D3300
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
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 A7R II« » 5.0 in 3.8 in 2.4 in 22.0 oz 290 Y Jun 2015 3,199- i Sony A7R II
Sony A7S II« » 5.0 in 3.8 in 2.4 in 22.1 oz 370 Y Sep 2015 2,999 i i Sony A7S II
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

Any camera purchase will naturally be influenced heavily by the price. 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 D7100 was launched at a markedly lower price (by 73 percent) than the A9, 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: Nikon D7100 vs Sony A9

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 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. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better 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 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 table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.

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 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 D3300« » APS-C 24.0 6000 40001080/60p24.312.8138582Nikon D3300
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
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 A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498Sony A7R II
Sony A7S II« » Full Frame 12.0 4240 28324K/30p23.613.3299385Sony A7S II
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 have a sensor with sufficiently fast read-out times for moving pictures, 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

Apart from body and sensor, cameras can and do differ across a variety 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 table below summarizes some of the other core capabilities of the Nikon D7100 and Sony A9 in connection with corresponding information for a sample of similar cameras. The full specs-sheets can be found in the camera manual or, for example, in the dpreview camera hub.

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 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 D3300« »optical n 3.0 921 fixed n 4000 5.0 Y n Nikon D3300
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
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 A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7R II
Sony A7S II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7S II
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

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? Which of the two cameras – the Nikon D7100 or the Sony A9 – has the upper hand? Below is a summary of the relative strengths of each of the two contestants.

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Advantages 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: Has 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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Reasons to prefer 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.
  • 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.
  • More legacy lens friendly: Can use many non-native lenses via adapters.
  • Sharper images: Has stabilization technology build-in to reduce the impact of hand-shake.
  • 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 (14 : 8 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.

D7100 08:14 A9

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the D7100 or the A9. 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 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 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 D3300« »Rec77/1004.5/54.5/54.5/5 Jan 2014 499- i Nikon D3300
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
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 A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i Sony A7R II
Sony A7S II« »Rec-4.5/55/55/5 Sep 2015 2,999 i i Sony A7S II
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

The above review scores should be interpreted with care, 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 comparisons of ratings among very different cameras or across long time periods have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

 

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 a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored. If you cannot find the camera you are interested in, please send me an email, and I will try to add information on that model to the database.

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