Nikon D5100 vs Sony A77
The Nikon D5100 and the Sony Alpha SLT-A77 are two digital cameras that were announced, respectively, in April 2011 and August 2011. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Nikon has a resolution of 16.1 megapixels, whereas the Sony provides 24 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 D5100 and the Sony Alpha SLT-A77? 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.
The physical size and weight of the Nikon D5100 and the Sony A77 are illustrated 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 size dimensions 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 A77 is notably larger (20 percent) than the Nikon D5100. Moreover, the A77 is markedly heavier (31 percent) than the D5100. It is noteworthy in this context that the A77 is splash and dust-proof, while the D5100 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. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.
The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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 D5100||5.0 in||3.8 in||3.1 in||19.8 oz||660||n||Apr 2011||749|
|2.||Sony A77||5.6 in||4.1 in||3.2 in||25.8 oz||470||Y||Aug 2011||1,399|
|3.||Canon T2i||5.1 in||3.9 in||2.4 in||18.7 oz||440||n||Feb 2010||699|
|4.||Nikon D5600||4.9 in||3.8 in||2.8 in||16.4 oz||970||n||Nov 2016||699|
|5.||Nikon D5300||4.9 in||3.9 in||3.0 in||16.9 oz||600||n||Oct 2013||799|
|6.||Nikon D3200||4.9 in||3.8 in||3.0 in||17.8 oz||540||n||Apr 2012||599|
|7.||Nikon D5200||5.1 in||3.9 in||3.1 in||19.6 oz||500||n||Nov 2012||749|
|8.||Nikon D7000||5.2 in||4.1 in||3.0 in||27.5 oz||1050||Y||Sep 2010||1,499|
|9.||Nikon D3100||4.9 in||3.8 in||3.0 in||17.8 oz||550||n||Aug 2010||599|
|10.||Nikon D5000||5.0 in||4.1 in||3.1 in||20.8 oz||510||n||Apr 2009||749|
|11.||Pentax K-3||5.2 in||3.9 in||3.0 in||28.2 oz||560||Y||Oct 2013||1,299|
|12.||Sony A6500||4.7 in||2.6 in||2.1 in||16.0 oz||350||Y||Oct 2016||1,399|
|13.||Sony A7 II||5.0 in||3.8 in||2.4 in||21.1 oz||350||Y||Nov 2014||1,999|
|14.||Sony A77 II||5.6 in||4.1 in||3.2 in||22.8 oz||480||Y||May 2014||1,199|
|15.||Sony A99||5.8 in||4.4 in||3.1 in||28.6 oz||500||Y||Sep 2012||2,799|
|16.||Sony NEX-5R||4.4 in||2.3 in||1.5 in||9.7 oz||330||n||Aug 2012||749|
|17.||Sony NEX-5N||4.4 in||2.3 in||1.5 in||9.5 oz||460||n||Aug 2011||699|
|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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The D5100 was launched at a markedly lower price (by 46 percent) than the A77, 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 imaging sensor is a crucial determinant 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. 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 more expensive and lead to bigger and heavier cameras and lenses.
Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the A77 is 1 percent smaller. They nevertheless have the same format factor of 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.
In terms of underlying technology, both cameras are build around CMOS sensors.
Despite having a slightly smaller sensor, the A77 offers a higher resolution of 24 megapixels, compared with 16.1 MP of the D5100. 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 3.91μm versus 4.80μm for the D5100). However, it should be noted that the A77 is a somewhat more recent model (by 4 months) than the D5100, and its sensor might have benefitted from technological advances during this time that partly offset its pixel-size disadvantage.
The resolution advantage of the Sony A77 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A77 for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the Nikon D5100 are 24.6 x 16.3 inches or 62.6 x 41.5 cm for good quality, 19.7 x 13.1 inches or 50.1 x 33.2 cm for very good quality, and 16.4 x 10.9 inches or 41.7 x 27.6 cm for excellent quality prints.
The Nikon D5100 has a native sensitivity range from ISO 100 to ISO 6400, which can be extended to ISO 100-25600. The corresponding ISO settings for the Sony Alpha SLT-A77 are ISO 100 to ISO 16000, with the possibility to increase the ISO range to 50-25600.
For many cameras, data on sensor performance has been reported by DXO Mark. This service determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). The Overall DXO ratings for the two cameras under consideration are close, suggesting that they provide similar imaging performance. 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 |
|13.||Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|14.||Sony A77 II||APS-C||24.0||6000||4000||1080/60p||..||..||..||..|
|15.||Sony A99||Full Frame||24.0||6000||4000||1080/60p||25.0||14.0||1555||89|
Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A77 provides a faster frame rate than the D5100. It can shoot movie footage at 1080/60p, while the Nikon is limited to 1080/30p.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the A77 has an electronic viewfinder (2359k dots), while the D5100 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 A77 offers a wider field of view (100%) than the one in the D5100 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A77 has a higher magnification (0.73x vs 0.51x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Nikon D5100 and Sony A77 in connection with corresponding information for a sample of similar cameras.
|13.||Sony A7 II||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y|
|14.||Sony A77 II||2359||Y||3.0||1229||full-flex||n||1/8000s||12.0||Y||Y|
One feature that differentiates the A77 and the D5100 is in-body image stabilization (IBIS). The A77 reduces the risk of handshake-induced blur with all attached lenses, while the D5100 offers no blur reduction with lenses that themselves do not provide optical image stabilization.Both cameras have an articulated rear screen that can be turned to be front-facing. This feature will be particularly appreciated by vloggers and photographers who are interested in taking selfies.
The Nikon D5100 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 D5100 writes its imaging data to SDXC cards, while the A77 uses SDXC or Memory Stick PRO Duo cards. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.
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 D5100 and Sony Alpha SLT-A77 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|13.||Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|14.||Sony A77 II||Y||stereo||mono||Y||-||mini||2.0||Y||Y||-|
Studio photographers will appreciate that the Sony A77 (unlike the D5100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Travel and landscape photographers will find it useful that the A77 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.
Both the D5100 and the A77 have been discontinued, but can regularly be found used on eBay. The D5100 was replaced by the Nikon D5200, while the A77 was followed by the Sony A77 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 conclusions can be drawn? Which of the two cameras – the Nikon D5100 or the Sony A77 – 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.
Advantages of the Nikon D5100:
- Better low-light sensitivity: Requires less light for good images (0.6 stops ISO advantage).
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More compact: Is smaller (128x97mm vs 143x104mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 172g or 23 percent) and hence easier to carry around.
- Longer lasting: Can take more shots (660 versus 470) on a single battery charge.
- More affordable: Was introduced into a lower priced category (46 percent cheaper at launch).
- More heavily discounted: Has been on the market for longer (launched in April 2011).
Reasons to prefer the Sony Alpha SLT-A77:
- More detail: Has more megapixels (24 vs 16.1MP), which boosts linear resolution by 22%.
- Better video: Provides higher movie framerates (1080/60p versus 1080/30p).
- 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 (0.73x vs 0.51x).
- Easier setting verification: Features a control panel on top to check shooting parameters.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (12 vs 4 flaps/sec) to capture the decisive moment.
- 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.
- Easier geotagging: Features an internal GPS sensor to log localization data.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- More modern: Was introduced somewhat (4 months) more recently.
If the number of relative strengths (bullet points above) is taken as a guide, the A77 is the clear winner of the contest (13 : 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. 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 D5100 and the Sony A77 place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing 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 says little about, for example, the shooting experience and imaging performance of the D5100 and the A77 in practical situations. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.
This is why expert reviews are important. The adjacent summary-table relays the overall verdicts of several of the most popular camera 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 D5100||5/5||+ +||76/100||4.5/5||4.5/5||Apr 2011||749|
|2.||Sony A77||5/5||91/100||81/100||..||5/5||Aug 2011||1,399|
|3.||Canon T2i||..||+ +||77/100||4/5||4.5/5||Feb 2010||699|
|4.||Nikon D5600||4/5||..||79/100||4.5/5||4/5||Nov 2016||699|
|5.||Nikon D5300||4/5||+ +||79/100||4.5/5||4.5/5||Oct 2013||799|
|6.||Nikon D3200||5/5||+ +||73/100||4.5/5||4.5/5||Apr 2012||599|
|7.||Nikon D5200||4/5||+ +||79/100||4.5/5||4.5/5||Nov 2012||749|
|8.||Nikon D7000||4/5||..||80/100||4.5/5||4.5/5||Sep 2010||1,499|
|9.||Nikon D3100||5/5||+ +||72/100||4.5/5||4.5/5||Aug 2010||599|
|10.||Nikon D5000||..||+ +||75/100||4/5||4.5/5||Apr 2009||749|
|11.||Pentax K-3||4/5||..||83/100||5/5||5/5||Oct 2013||1,299|
|12.||Sony A6500||5/5||+ +||85/100||4.5/5||4.5/5||Oct 2016||1,399|
|13.||Sony A7 II||5/5||+||82/100||4.5/5||5/5||Nov 2014||1,999|
|14.||Sony A77 II||4/5||..||80/100||4.5/5||5/5||May 2014||1,199|
|15.||Sony A99||5/5||..||84/100||4.5/5||4.5/5||Sep 2012||2,799|
|16.||Sony NEX-5R||..||..||..||4.5/5||4.5/5||Aug 2012||749|
|17.||Sony NEX-5N||3/5||+ +||79/100||4.5/5||4.5/5||Aug 2011||699|
|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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. It should also be noted that some of the review sites have over time altered the way they render their verdicts.
Other camera comparisons
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Specifications: Nikon D5100 vs Sony A77
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 D5100||Sony A77|
|Camera Type||Digital single lens reflex||Digital single lens reflex|
|Camera Lens||Nikon F mount lenses||Sony A mount lenses|
|Launch Date||April 2011||August 2011|
|Launch Price||USD 749||USD 1,399|
|Sensor Specs||Nikon D5100||Sony A77|
|Sensor Format||APS-C Sensor||APS-C Sensor|
|Sensor Size||23.6 x 15.7 mm||23.5 x 15.6 mm|
|Sensor Area||370.52 mm2||366.6 mm2|
|Sensor Diagonal||28.3 mm||28.2 mm|
|Sensor Resolution||16.1 Megapixels||24 Megapixels|
|Image Resolution||4928 x 3264 pixels||6000 x 4000 pixels|
|Pixel Pitch||4.80 μm||3.91 μm|
|Pixel Density||4.34 MP/cm2||6.55 MP/cm2|
|Moiré control||Anti-Alias filter||Anti-Alias filter|
|Movie Capability||1080/30p Video||1080/60p Video|
|ISO Setting||100 - 6,400 ISO||100 - 16,000 ISO|
|ISO Boost||100 - 25,600 ISO||50 - 25,600 ISO|
|Image Processor||EXPEED 2||BIONZ X|
|DXO Sensor Quality (score)||80||78|
|DXO Color Depth (bits)||23.5||24.0|
|DXO Dynamic Range (EV)||13.6||13.2|
|DXO Low Light (ISO)||1183||801|
|Screen Specs||Nikon D5100||Sony A77|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||95%||100%|
|Viewfinder Resolution||2359k dots|
|Top-Level Screen||no Top Display||Control Panel|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||921k dots||921k dots|
|LCD Attachment||Swivel screen||Fully flexible screen|
|Shooting Specs||Nikon D5100||Sony A77|
|Focus System||Phase-detect AF||Phase-detect AF|
|Manual Focusing Aid||no Peaking Feature||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/8000s|
|Continuous Shooting||4 shutter flaps/s||12 shutter flaps/s|
|Shutter Life Expectancy||100 000 actuations||150 000 actuations|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||Lens stabilization only||In-body stabilization|
|Fill Flash||Build-in Flash||Build-in Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Single card slot||Single card slot|
|UHS card support||UHS-I||UHS-I|
|Connectivity Specs||Nikon D5100||Sony A77|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||mini HDMI||mini HDMI|
|Microphone Port||External MIC port||External MIC port|
|Wifi Support||no Wifi||no Wifi|
|Geotagging||no internal GPS||GPS built-in|
|Body Specs||Nikon D5100||Sony A77|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||660 shots per charge||470 shots per charge|
128 x 97 x 79 mm
(5.0 x 3.8 x 3.1 in)
143 x 104 x 81 mm
(5.6 x 4.1 x 3.2 in)
|Camera Weight||560 g (19.8 oz)||732 g (25.8 oz)|
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