Nikon D7100 vs 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 megapixels.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
|Nikon D7100||Sony A9|
|Digital single lens reflex||Mirrorless system camera|
|Nikon F mount lenses||Sony E mount lenses|
|24 MP, APS-C Sensor||24 MP, Full Frame Sensor|
|1080/60p Video||4K/30p Video|
|ISO 100-6,400 (50 - 25,600)||ISO 100-51,200 (50 - 204,800)|
|Optical viewfinder||Electronic viewfinder (3686k dots)|
|3.2 LCD, 1229k dots||3.0 LCD, 1440k dots|
|Fixed screen (not touch-sensitive)||Tilting touchscreen|
|6 shutter flaps per second||20 shutter flaps per second|
|Lens stabilization only||In-body stabilization|
|Weathersealed body||Weathersealed body|
|950 shots per battery charge||650 shots per battery charge|
|136 x 107 x 76 mm, 765 g||127 x 96 x 63 mm, 673 g|
Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D7100 and the Sony Alpha A9? 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.
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.
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 compare the optics available 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 power pack in the A9 can be charged via the USB port, which can be very convenient when travelling.
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.
|Nikon D7100||136 mm||107 mm||76 mm||765 g||950||Y||Feb 2013||1,199|
|Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|Canon 80D||139 mm||105 mm||79 mm||730 g||960||Y||Feb 2016||1,199|
|Canon 70D||139 mm||104 mm||79 mm||755 g||920||Y||Jul 2013||1,199|
|Nikon D7500||136 mm||104 mm||73 mm||720 g||950||Y||Apr 2017||1,299|
|Nikon D500||147 mm||115 mm||81 mm||860 g||1240||Y||Jan 2016||1,999|
|Nikon D7200||136 mm||107 mm||76 mm||765 g||1110||Y||Mar 2015||1,199|
|Nikon D750||141 mm||113 mm||78 mm||750 g||1230||Y||Sep 2014||2,299|
|Nikon D610||141 mm||113 mm||82 mm||850 g||900||Y||Oct 2013||1,999|
|Nikon D600||141 mm||113 mm||82 mm||850 g||900||Y||Sep 2012||2,099|
|Nikon D7000||132 mm||105 mm||77 mm||780 g||1050||Y||Sep 2010||1,499|
|Panasonic GH5||139 mm||98 mm||87 mm||725 g||410||Y||Jan 2017||1,999|
|Sony A9 II||129 mm||96 mm||76 mm||678 g||690||Y||Oct 2019||4,499|
|Sony A7 III||127 mm||96 mm||74 mm||650 g||610||Y||Feb 2018||1,999|
|Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199|
|Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
|Sony RX10||129 mm||88 mm||102 mm||813 g||420||Y||Oct 2013||1,299|
Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
(1) Number of images that can be taken on a full battery charge according to the CIPA-standard; (2) Official announcement.
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.
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.
Even though the A9 has a larger sensor, both cameras offer the same resolution of 24 megapixels. 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.
The A9 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
The Nikon D7100 has a native sensitivity range from ISO 100 to ISO 6400, which can be extended to ISO 50-25600. The corresponding ISO settings for the Sony Alpha A9 are ISO 100 to ISO 51200, with the possibility to increase the ISO range to 50-204800.
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.
|Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|Nikon D750||Full Frame||24.2||6016||4016||1080/60p||24.8||14.5||2956||93|
|Nikon D610||Full Frame||24.2||6016||4016||1080/30p||25.1||14.4||2925||94|
|Nikon D600||Full Frame||24.2||6016||4016||1080/30p||25.1||14.2||2980||94|
|Panasonic GH5||Four Thirds||20.2||5184||3888||4K/60p||23.9||13.0||807||77|
|Sony A9 II||Full Frame||24.0||6000||4000||4K/30p||25.0||14.0||3434||93|
|Sony A7 III||Full Frame||24.0||6000||4000||4K/30p||25.0||14.7||3730||96|
|Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
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.
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 viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the A9 has a higher magnification than the one of the D7100 (0.78x vs 0.63x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The following table reports on some other key feature differences and similarities of the Nikon D7100, the Sony A9, and comparable cameras.
|Sony A9 II||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|Sony A7 III||2359||n||3.0||922||tilting||Y||1/8000s||10.0||n||Y|
|Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|Sony A7 II||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y|
One difference between the cameras concerns the presence of an on-board flash. The D7100 has one, while the A9 does not. While the built-in flash of the D7100 is not very powerful, it can at times be useful as a fill-in light.
The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the A9 is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).
The Nikon D7100 has an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.
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. The A9 supports UHS-II cards (on its first slot), while the D7100 can use UHS-I cards.
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 Nikon D7100 and Sony Alpha A9 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
|Sony A9 II||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Sony A7 III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A9 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the D7100 does not provide wifi capability.
Studio photographers will appreciate that the Sony A9 (unlike the D7100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the D7100 and the A9 have been discontinued, but can regularly be found used on eBay. The D7100 was replaced by the Nikon D7200, while the A9 was followed by the Sony A9 II. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Nikon and Sony websites.
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.
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.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- 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).
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).
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- More framing info: Has an electronic viewfinder that displays shooting data.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.63x).
- 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.
- Easier travel charging: Can be conveniently charged via its USB port.
- Sharper images: Has stabilization technology built-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 built 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.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- 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 (22 : 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 before making a camera decision. A professional wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports 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 Nikon D7100 and the Sony A9 place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens Camera listings whether the two cameras rank among the cream of the crop.
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 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 ratings of the cameras as published by some of the major camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, and photographyblog). 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.
|Nikon D7100||+ +||85/100||4.5/5||5/5||4.5/5||Feb 2013||1,199|
|Sony A9||+ +||89/100||5/5||5/5||5/5||Apr 2017||4,499|
|Canon 80D||+ +||84/100||4.5/5||4.5/5||4.5/5||Feb 2016||1,199|
|Canon 70D||+ +||83/100||4.5/5||4.5/5||5/5||Jul 2013||1,199|
|Nikon D7500||+ +||86/100||5/5||4.5/5||4.5/5||Apr 2017||1,299|
|Nikon D500||+ +||91/100||4.5/5||5/5||5/5||Jan 2016||1,999|
|Nikon D7200||+ +||84/100||4.5/5||4/5||4.5/5||Mar 2015||1,199|
|Nikon D750||+ +||90/100||4.5/5||5/5||4.5/5||Sep 2014||2,299|
|Nikon D610||+ +||87/100||4.5/5||4.5/5||4.5/5||Oct 2013||1,999|
|Nikon D600||+ +||87/100||5/5||4.5/5||4.5/5||Sep 2012||2,099|
|Nikon D7000||..||80/100||4.5/5||5/5||4.5/5||Sep 2010||1,499|
|Panasonic GH5||+ +||85/100||4.5/5||5/5||5/5||Jan 2017||1,999|
|Sony A9 II||..||90/100||5/5||..||5/5||Oct 2019||4,499|
|Sony A7 III||+ +||89/100||5/5||5/5||5/5||Feb 2018||1,999|
|Sony A7R III||+ +||90/100||4.5/5||5/5||5/5||Oct 2017||3,199|
|Sony A7 II||+||82/100||4.5/5||5/5||5/5||Nov 2014||1,999|
|Sony RX10||+||80/100||4.5/5||4.5/5||4.5/5||Oct 2013||1,299|
|Notes: (+ +) 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. 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
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Specifications: Nikon D7100 vs Sony A9
Below is a side-by-side comparison of the specs of the two cameras to facilitate a quick review of their differences and common features.
|Camera Model||Nikon D7100||Sony A9|
|Camera Type||Digital single lens reflex||Mirrorless system camera|
|Camera Lens||Nikon F mount lenses||Sony E mount lenses|
|Launch Date||February 2013||April 2017|
|Launch Price||USD 1,199||USD 4,499|
|Sensor Specs||Nikon D7100||Sony A9|
|Sensor Format||APS-C Sensor||Full Frame Sensor|
|Sensor Size||23.5 x 15.6 mm||35.6 x 23.8 mm|
|Sensor Area||366.6 mm2||847.28 mm2|
|Sensor Diagonal||28.2 mm||42.8 mm|
|Sensor Resolution||24 Megapixels||24 Megapixels|
|Image Resolution||6000 x 4000 pixels||6000 x 4000 pixels|
|Pixel Pitch||3.91 μm||5.94 μm|
|Pixel Density||6.55 MP/cm2||2.83 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||1080/60p Video||4K/30p Video|
|ISO Setting||100 - 6,400 ISO||100 - 51,200 ISO|
|ISO Boost||50 - 25,600 ISO||50 - 204,800 ISO|
|Image Processor||EXPEED 4||BIONZ X|
|DXO Sensor Quality (score)||83||92|
|DXO Color Depth (bits)||24.2||24.9|
|DXO Dynamic Range (EV)||13.7||13.3|
|DXO Low Light (ISO)||1256||3517|
|Screen Specs||Nikon D7100||Sony A9|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||3686k dots|
|Top-Level Screen||Control Panel||no Top Display|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.2inch||3.0inch|
|LCD Resolution||1229k dots||1440k dots|
|LCD Attachment||Fixed screen||Tilting screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Nikon D7100||Sony A9|
|Focus System||Phase-detect AF||On-Sensor Phase-detect|
|Manual Focusing Aid||no Peaking Feature||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/8000s|
|Continuous Shooting||6 shutter flaps/s||20 shutter flaps/s|
|Shutter Life Expectancy||150 000 actuations||500 000 actuations|
|Electronic Shutter||no E-Shutter||up to 1/32000s|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||Lens stabilization only||In-body stabilization|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Dual card slots||Dual card slots|
|UHS card support||UHS-I||Single UHS-II|
|Connectivity Specs||Nikon D7100||Sony A9|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||mini HDMI||micro HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||Headphone port||Headphone port|
|Wifi Support||no Wifi||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Bluetooth Support||no Bluetooth||Bluetooth built-in|
|Body Specs||Nikon D7100||Sony A9|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||950 shots per charge||650 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
136 x 107 x 76 mm
(5.4 x 4.2 x 3.0 in)
127 x 96 x 63 mm
(5.0 x 3.8 x 2.5 in)
|Camera Weight||765 g (27.0 oz)||673 g (23.7 oz)|
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