Nikon D3100 vs Sony A7S III
The Nikon D3100 and the Sony Alpha 7S III are two digital cameras that were announced, respectively, in August 2010 and July 2020. The D3100 is a DSLR, while the A7S III is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (D3100) and a full frame (A7S III) sensor. The Nikon has a resolution of 14.2 megapixels, whereas the Sony provides 12 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D3100 and the Sony Alpha 7S III? 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 D3100 and the Sony A7S III is provided in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth dimensions are rounded to the nearest millimeter.
The D3100 can be obtained in two different colors (black, red), while the A7S III is only available in black.
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7S III is somewhat larger (3 percent) than the Nikon D3100. Moreover, the A7S III is substantially heavier (38 percent) than the D3100. It is noteworthy in this context that the A7S III is splash and dust-proof, while the D3100 does not feature any corresponding weather-sealing.
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 (D3100) and the Sony FE Lens Catalog (A7S III). Mirrorless cameras, such as the A7S III, 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 D3100 gets 550 shots out of its EN-EL14 battery, while the A7S III can take 600 images on a single charge of its NP-FZ100 power pack. The power pack in the A7S III can be charged via the USB port, which can be very convenient when travelling.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.
|1.||Nikon D3100||124 mm||96 mm||75 mm||505 g||550||n||Aug 2010||599|
|2.||Sony A7S III||127 mm||97 mm||81 mm||699 g||600||Y||Jul 2020||3,499|
|3.||Nikon D3200||125 mm||96 mm||77 mm||505 g||540||n||Apr 2012||599|
|4.||Nikon D5100||128 mm||97 mm||79 mm||560 g||660||n||Apr 2011||749|
|5.||Nikon D7000||132 mm||105 mm||77 mm||780 g||1050||Y||Sep 2010||1,499|
|6.||Nikon D3000||126 mm||97 mm||64 mm||536 g||500||n||Jul 2009||599|
|7.||Nikon D5000||127 mm||104 mm||80 mm||590 g||510||n||Apr 2009||749|
|8.||Nikon D60||126 mm||94 mm||64 mm||522 g||500||n||Jan 2008||629|
|9.||Nikon D40X||124 mm||94 mm||64 mm||522 g||520||n||Mar 2007||729|
|10.||Nikon D40||124 mm||94 mm||64 mm||522 g||470||n||Nov 2006||499|
|11.||Sony A7R IV||129 mm||96 mm||78 mm||665 g||670||Y||Jul 2019||3,499|
|12.||Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199|
|13.||Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|14.||Sony A7R II||127 mm||96 mm||60 mm||625 g||290||Y||Jun 2015||3,199|
|15.||Sony A7S II||127 mm||96 mm||60 mm||627 g||370||Y||Sep 2015||2,999|
|16.||Sony NEX-5N||111 mm||59 mm||38 mm||269 g||460||n||Aug 2011||699|
|17.||Sony NEX-C3||110 mm||60 mm||33 mm||225 g||400||n||Jun 2011||599|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will obviously take relative prices into account. 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 D3100 was launched at a markedly lower price (by 83 percent) than the A7S III, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.
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. 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 associated with larger, more expensive camera bodies and lenses.
Of the two cameras under consideration, the Nikon D3100 features an APS-C sensor and the Sony A7S III a full frame sensor. The sensor area in the A7S III is 138 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.
Despite having a smaller sensor, the Nikon D3100 offers a higher resolution of 14.2 megapixels, compared with 12 MP of the Sony A7S III. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 5.01μm versus 8.40μm for the A7S III). Moreover, it should be noted that the A7S III is much more recent (by 9 years and 11 months) than the D3100, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units.
The resolution advantage of the Nikon D3100 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the D3100 for good quality output (200 dots per inch) amounts to 23 x 15.4 inches or 58.5 x 39 cm, for very good quality (250 dpi) 18.4 x 12.3 inches or 46.8 x 31.2 cm, and for excellent quality (300 dpi) 15.4 x 10.2 inches or 39 x 26 cm. The corresponding values for the Sony A7S III are 21.2 x 14.2 inches or 53.8 x 36 cm for good quality, 17 x 11.3 inches or 43.1 x 28.8 cm for very good quality, and 14.1 x 9.4 inches or 35.9 x 24 cm for excellent quality prints.
The Nikon D3100 has a native sensitivity range from ISO 100 to ISO 3200, which can be extended to ISO 100-12800. The corresponding ISO settings for the Sony Alpha 7S III are ISO 80 to ISO 102400, with the possibility to increase the ISO range to 40-409600.
For many cameras, data on sensor performance has been reported by DXO Mark. 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 A7S III offers substantially better image quality than the D3100 (overall score 19 points higher). The advantage is based on 1.2 bits higher color depth, 2.6 EV in additional dynamic range, and 1.5 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.
| DXO |
|2.||Sony A7S III||Full Frame||12.0||4240||2832||4K/120p||23.7||13.9||2520||86|
|11.||Sony A7R IV||Full Frame||60.2||9504||6336||4K/30p||26.0||14.8||3344||99|
|12.||Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|13.||Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|14.||Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|15.||Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A7S III provides a better video resolution than the D3100. It can shoot movie footage at 4K/120p, while the Nikon is limited to 1080/24p.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the A7S III has an electronic viewfinder (9440k dots), while the D3100 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 viewfinder in the A7S III offers a wider field of view (100%) than the one in the D3100 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A7S III has a higher magnification (0.91x vs 0.53x), 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 D3100, the Sony A7S III, and comparable cameras.
|2.||Sony A7S III||9440||n||3.0||1440||swivel||Y||1/8000s||10.0||n||Y|
|11.||Sony A7R IV||5760||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|12.||Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|14.||Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|15.||Sony A7S II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
One difference between the cameras concerns the presence of an on-board flash. The D3100 has one, while the A7S III does not. While the built-in flash of the D3100 is not very powerful, it can at times be useful as a fill-in light.The A7S III has an articulated screen that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in taking selfies. In contrast, the D3100 does not have a selfie-screen.
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 A7S III 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 D3100 writes its imaging data to SDXC cards, while the A7S III uses CFexpress or SDXC cards. The A7S III features dual card slots, which can be very useful in case a memory card fails. In contrast, the D3100 only has one slot. The A7S III supports UHS-II cards (on both slots), while the D3100 cannot take advantage of Ultra High Speed SD 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 D3100 and Sony Alpha 7S III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|2.||Sony A7S III||Y||stereo||mono||Y||Y||full||3.2||Y||-||Y|
|11.||Sony A7R IV||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|12.||Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|14.||Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|15.||Sony A7S II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A7S III offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the D3100 does not provide wifi capability.
The A7S III is a recent model that features in the current product line-up of Sony. In contrast, the D3100 has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the D3100 was succeeded by the Nikon D3200. 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 conclusions can be drawn? Which of the two cameras – the Nikon D3100 or the Sony A7S III – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.
Arguments in favor of the Nikon D3100:
- More detail: Offers more megapixels (14.2 vs 12MP) with a 9% higher linear resolution.
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Less heavy: Is lighter (by 194g or 28 percent) and hence easier to carry around.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- More affordable: Was introduced into a lower priced category (83 percent cheaper at launch).
- More heavily discounted: Has been available for much longer (launched in August 2010).
Reasons to prefer the Sony Alpha 7S III:
- Better image quality: Scores substantially higher (19 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 (2.6 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (1.5 stops ISO advantage).
- Better video: Provides higher definition movie capture (4K/120p vs 1080/24p).
- Better sound: Can connect to an external microphone for higher quality sound recording.
- Better sound control: Has a headphone port that enables audio monitoring while recording.
- More framing info: Has an electronic viewfinder that displays shooting data.
- More complete view: Has a viewfinder with a larger field of view (100% vs 95%).
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.91x vs 0.53x).
- More detailed LCD: Has a higher resolution rear screen (1440k vs 230k dots).
- More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (10 vs 3 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- Easier travel charging: Can be conveniently charged via its USB port.
- Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
- 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.
- Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
- Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
- Easier wireless transfer: Supports Bluetooth for image sharing without cables.
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- Faster buffer clearing: Supports Ultra High Speed (UHS-II) SDXC cards on both slots.
- More modern: Reflects 9 years and 11 months of technical progress since the D3100 launch.
If the number of relative strengths (bullet points above) is taken as a guide, the A7S III is the clear winner of the contest (28 : 6 points). However, the relevance of individual strengths will vary across photographers, so that you might want to apply your own weighing scheme to the summary points when reflecting and deciding on a new camera. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro 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 D3100 and the Sony A7S III 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 technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the D3100 and the A7S III 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 why expert reviews are important. The table below provides a synthesis of the camera assessments of some of the best known photo-gear review sites (amateurphotographer [AP], cameralabs [CL], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). 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.
|1.||Nikon D3100||5/5||+ +||72/100||4.5/5||4.5/5||Aug 2010||599|
|2.||Sony A7S III||..||+ +||91/100||4.5/5||5/5||Jul 2020||3,499|
|3.||Nikon D3200||5/5||+ +||73/100||4.5/5||4.5/5||Apr 2012||599|
|4.||Nikon D5100||5/5||+ +||76/100||4.5/5||4.5/5||Apr 2011||749|
|5.||Nikon D7000||4/5||..||80/100||4.5/5||4.5/5||Sep 2010||1,499|
|6.||Nikon D3000||..||+||72/100||4/5||4.5/5||Jul 2009||599|
|7.||Nikon D5000||..||+ +||75/100||4/5||4.5/5||Apr 2009||749|
|8.||Nikon D60||..||80/100||+ +||4/5||4.5/5||Jan 2008||629|
|9.||Nikon D40X||..||79/100||+ +||4/5||4/5||Mar 2007||729|
|10.||Nikon D40||..||81/100||+ +||o||4.5/5||Nov 2006||499|
|11.||Sony A7R IV||5/5||+||91/100||4.5/5||5/5||Jul 2019||3,499|
|12.||Sony A7R III||..||+ +||90/100||4.5/5||5/5||Oct 2017||3,199|
|13.||Sony A9||5/5||+ +||89/100||5/5||5/5||Apr 2017||4,499|
|14.||Sony A7R II||5/5||+ +||90/100||5/5||5/5||Jun 2015||3,199|
|15.||Sony A7S II||5/5||+||..||4.5/5||5/5||Sep 2015||2,999|
|16.||Sony NEX-5N||3/5||+ +||79/100||4.5/5||4.5/5||Aug 2011||699|
|17.||Sony NEX-C3||3/5||+ +||74/100||4.5/5||4/5||Jun 2011||599|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The review scores listed above should be treated 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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.
Other camera comparisons
Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just use the search menu below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.
Specifications: Nikon D3100 vs Sony A7S III
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 D3100||Sony A7S III|
|Camera Type||Digital single lens reflex||Mirrorless system camera|
|Camera Lens||Nikon F mount lenses||Sony E mount lenses|
|Launch Date||August 2010||July 2020|
|Launch Price||USD 599||USD 3,499|
|Sensor Specs||Nikon D3100||Sony A7S III|
|Sensor Format||APS-C Sensor||Full Frame Sensor|
|Sensor Size||23.1 x 15.4 mm||35.6 x 23.8 mm|
|Sensor Area||355.74 mm2||847.28 mm2|
|Sensor Diagonal||27.8 mm||42.8 mm|
|Sensor Resolution||14.2 Megapixels||12 Megapixels|
|Image Resolution||4608 x 3072 pixels||4240 x 2832 pixels|
|Pixel Pitch||5.01 μm||8.40 μm|
|Pixel Density||3.98 MP/cm2||1.42 MP/cm2|
|Moiré control||Anti-Alias filter||Anti-Alias filter|
|Movie Capability||1080/24p Video||4K/120p Video|
|ISO Setting||100 - 3,200 ISO||80 - 102,400 ISO|
|ISO Boost||100 - 12,800 ISO||40 - 409,600 ISO|
|Image Processor||EXPEED 2||BIONZ XR|
|DXO Sensor Quality (score)||67||86|
|DXO Color Depth (bits)||22.5||23.7|
|DXO Dynamic Range (EV)||11.3||13.9|
|DXO Low Light (ISO)||919||2520|
|Screen Specs||Nikon D3100||Sony A7S III|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||95%||100%|
|Viewfinder Resolution||9440k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||230k dots||1440k dots|
|LCD Attachment||Fixed screen||Swivel screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Nikon D3100||Sony A7S III|
|Focus System||Phase-detect AF||Contrast-detect AF|
|Manual Focusing Aid||no Peaking Feature||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/8000s|
|Continuous Shooting||3 shutter flaps/s||10 shutter flaps/s|
|Shutter Life Expectancy||100 000 actuations||200 000 actuations|
|Electronic Shutter||no E-Shutter||YES|
|Image Stabilization||Lens stabilization only||In-body stabilization|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||CFexpress or SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||no||Dual UHS-II|
|Connectivity Specs||Nikon D3100||Sony A7S III|
|USB Connector||USB 2.0||USB 3.2|
|HDMI Port||mini HDMI||full HDMI|
|Microphone Port||no MIC socket||External MIC port|
|Headphone Socket||no Headphone port||Headphone port|
|Wifi Support||no Wifi||Wifi built-in|
|Bluetooth Support||no Bluetooth||Bluetooth built-in|
|Body Specs||Nikon D3100||Sony A7S III|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||550 shots per charge||600 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
124 x 96 x 75 mm
(4.9 x 3.8 x 3.0 in)
127 x 97 x 81 mm
(5.0 x 3.8 x 3.2 in)
|Camera Weight||505 g (17.8 oz)||699 g (24.7 oz)|
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