Nikon D3100 vs Pentax K-3 III
The Nikon D3100 and the Pentax K-3 III are two digital cameras that were revealed to the public, respectively, in August 2010 and March 2021. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Nikon has a resolution of 14.2 megapixels, whereas the Pentax provides 25.6 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Check D3100 offers at
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Check K-3 III price at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D3100 and the Pentax K-3 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.
Body comparison
The side-by-side display below illustrates the physical size and weight of the Nikon D3100 and the Pentax K-3 III. 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.
The D3100 can be obtained in two different colors (black, red), while the K-3 III is also available in two color-versions, but different ones (black, silver).



If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-3 III is notably larger (18 percent) than the Nikon D3100. Moreover, the K-3 III is substantially heavier (62 percent) than the D3100. It is noteworthy in this context that the K-3 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. 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.
Concerning battery life, the D3100 gets 550 shots out of its Nikon EN-EL14 battery, while the K-3 III can take 800 images on a single charge of its Pentax D-LI90 power pack.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. In case you want to display and compare another camera duo, you can use the CAM-parator app to select your camera combination among a large number of options.

| Camera Model |
Camera Width |
Camera Height |
Camera Depth |
Camera Weight |
Battery Life |
Weather Sealing |
Camera Launch |
Launch Price |
Street Price |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Nikon D3100 | 124 mm | 96 mm | 75 mm | 505 g | 550 | n | Aug 2010 | US$ 599 | ebay.com | |
| 2. | Pentax K-3 III | 135 mm | 104 mm | 74 mm | 820 g | 800 | Y | Mar 2021 | US$ 1 999 | amazon.com | |
| 3. | Fujifilm X-H1 | 140 mm | 97 mm | 86 mm | 673 g | 310 | Y | Feb 2018 | US$ 1 899 | ebay.com | |
| 4. | Nikon D40 | 124 mm | 94 mm | 64 mm | 522 g | 470 | n | Nov 2006 | US$ 499 | ebay.com | |
| 5. | Nikon D40X | 124 mm | 94 mm | 64 mm | 522 g | 520 | n | Mar 2007 | US$ 729 | ebay.com | |
| 6. | Nikon D60 | 126 mm | 94 mm | 64 mm | 522 g | 500 | n | Jan 2008 | US$ 629 | ebay.com | |
| 7. | Nikon D3000 | 126 mm | 97 mm | 64 mm | 536 g | 500 | n | Jul 2009 | US$ 599 | ebay.com | |
| 8. | Nikon D3200 | 125 mm | 96 mm | 77 mm | 505 g | 540 | n | Apr 2012 | US$ 599 | ebay.com | |
| 9. | Nikon D5000 | 127 mm | 104 mm | 80 mm | 590 g | 510 | n | Apr 2009 | US$ 749 | ebay.com | |
| 10. | Nikon D5100 | 128 mm | 97 mm | 79 mm | 560 g | 660 | n | Apr 2011 | US$ 749 | ebay.com | |
| 11. | Nikon D7000 | 132 mm | 105 mm | 77 mm | 780 g | 1050 | Y | Sep 2010 | US$ 1 499 | ebay.com | |
| 12. | Pentax K-3 | 131 mm | 100 mm | 77 mm | 800 g | 560 | Y | Oct 2013 | US$ 1 299 | ebay.com | |
| 13. | Pentax K-3 II | 131 mm | 100 mm | 77 mm | 800 g | 720 | Y | Apr 2015 | US$ 1 099 | ebay.com | |
| 14. | Pentax K-70 | 126 mm | 93 mm | 74 mm | 688 g | 410 | Y | Jun 2016 | US$ 649 | ebay.com | |
| 15. | Pentax KP | 132 mm | 101 mm | 76 mm | 703 g | 390 | Y | Jan 2017 | US$ 1 099 | ebay.com | |
| 16. | Sony NEX-5N | 111 mm | 59 mm | 38 mm | 269 g | 460 | n | Aug 2011 | US$ 699 | ebay.com | |
| 17. | Sony NEX-C3 | 110 mm | 60 mm | 33 mm | 225 g | 400 | n | Jun 2011 | US$ 599 | ebay.com | |
| Note: 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 70 percent) than the K-3 III, 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.
Sensor comparison
The size of the sensor inside a digital camera is one of the key determinants 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 associated with larger, more expensive camera bodies and lenses.
Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the K-3 III is 1 percent bigger. 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.

With 25.6MP, the K-3 III offers a higher resolution than the D3100 (14.2MP), but the K-3 III has smaller individual pixels (pixel pitch of 3.76μm versus 5.01μm for the D3100). Yet, the K-3 III is a much more recent model (by 10 years and 7 months) than the D3100, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the K-3 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the Pentax K-3 III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-3 III for good quality output (200 dots per inch) amounts to 31 x 20.6 inches or 78.6 x 52.4 cm, for very good quality (250 dpi) 24.8 x 16.5 inches or 62.9 x 41.9 cm, and for excellent quality (300 dpi) 20.6 x 13.8 inches or 52.4 x 35 cm. The corresponding values for the Nikon D3100 are 23 x 15.4 inches or 58.5 x 39 cm for good quality, 18.4 x 12.3 inches or 46.8 x 31.2 cm for very good quality, and 15.4 x 10.2 inches or 39 x 26 cm for excellent quality prints.
Unlike the D3100, the K-3 III has the capacity to capture high quality composite images (YESMP) by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).
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 Pentax K-3 III are ISO 100 to ISO 160000 (no boost).
Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. This service is based on lab testing and assigns an overall score to each camera sensor, as well as ratings for dynamic range ("DXO Landscape"), color depth ("DXO Portrait"), and low-light sensitivity ("DXO Sports"). The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.

| Camera Model |
Sensor Class |
Resolution (MP) |
Horiz. Pixels |
Vert. Pixels |
Video Format |
DXO Portrait |
DXO Landscape |
DXO Sports |
DXO Overall |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Nikon D3100 | APS-C | 14.2 | 4608 | 3072 | 1080/24p | 22.5 | 11.3 | 919 | 67 | |
| 2. | Pentax K-3 III | APS-C | 25.6 | 6192 | 4128 | 4K/30p | 24.2 | 13.7 | 2083 | 85 | |
| 3. | Fujifilm X-H1 | APS-C | 24.0 | 6000 | 4000 | 4K/30p | 24.0 | 13.3 | 1806 | 82 | |
| 4. | Nikon D40 | APS-C | 6.0 | 3008 | 2000 | none | 21.0 | 11.0 | 561 | 56 | |
| 5. | Nikon D40X | APS-C | 10.0 | 3872 | 2592 | none | 22.4 | 11.4 | 516 | 63 | |
| 6. | Nikon D60 | APS-C | 10.0 | 3872 | 2592 | none | 22.5 | 11.4 | 562 | 65 | |
| 7. | Nikon D3000 | APS-C | 10.0 | 3872 | 2592 | none | 22.3 | 11.1 | 563 | 62 | |
| 8. | Nikon D3200 | APS-C | 24.1 | 6016 | 4000 | 1080/30p | 24.1 | 13.2 | 1131 | 81 | |
| 9. | Nikon D5000 | APS-C | 12.2 | 4288 | 2848 | 720/24p | 22.7 | 12.5 | 868 | 72 | |
| 10. | Nikon D5100 | APS-C | 16.1 | 4928 | 3264 | 1080/30p | 23.5 | 13.6 | 1183 | 80 | |
| 11. | Nikon D7000 | APS-C | 16.1 | 4928 | 3264 | 1080/24p | 23.5 | 13.9 | 1167 | 80 | |
| 12. | Pentax K-3 | APS-C | 24.1 | 6016 | 4000 | 1080/60i | 23.7 | 13.4 | 1216 | 80 | |
| 13. | Pentax K-3 II | APS-C | 24.1 | 6016 | 4000 | 1080/60i | 23.6 | 13.6 | 1106 | 80 | |
| 14. | Pentax K-70 | APS-C | 24.0 | 6000 | 4000 | 1080/60i | 23.8 | 13.1 | 1639 | 80 | |
| 15. | Pentax KP | APS-C | 24.1 | 6016 | 4000 | 1080/60i | 23.9 | 13.2 | 1699 | 81 | |
| 16. | Sony NEX-5N | APS-C | 16.0 | 4912 | 3264 | 1080/60i | 23.6 | 12.7 | 1079 | 77 | |
| 17. | Sony NEX-C3 | APS-C | 16.0 | 4912 | 3264 | 720/30p | 22.7 | 12.2 | 1083 | 73 | |
| Note: DXO values in italics represent estimates based on sensor size and age. | |||||||||||
Many modern cameras cannot only take still pictures, but also record videos. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the K-3 III provides a better video resolution than the D3100. It can shoot movie footage at 4K/30p, while the Nikon is limited to 1080/24p.
Feature comparison
Beyond body and sensor, cameras can and do differ across a range of features. The D3100 and the K-3 III are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The viewfinder in the K-3 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 K-3 III has a higher magnification (0.70x 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 Pentax K-3 III, and comparable cameras.

| Camera Model |
Viewfinder (Type or 000 dots) |
Control Panel (yes/no) |
LCD Specifications (inch/000 dots) |
LCD Attach- ment |
Touch Screen (yes/no) |
Max Shutter Speed * |
Max Shutter Flaps * |
Built-in Flash (yes/no) |
Built-in Image Stab |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Nikon D3100 | optical | n | 3.0 / 230 | fixed | n | 1/4000s | 3.0/s | Y | n | |
| 2. | Pentax K-3 III | optical | Y | 3.2 / 1620 | fixed | Y | 1/8000s | 12.0/s | n | Y | |
| 3. | Fujifilm X-H1 | 3690 | Y | 3.0 / 1040 | full-flex | Y | 1/8000s | 14.0/s | n | Y | |
| 4. | Nikon D40 | optical | n | 2.5 / 230 | fixed | n | 1/4000s | 2.5/s | Y | n | |
| 5. | Nikon D40X | optical | n | 2.5 / 230 | fixed | n | 1/4000s | 3.0/s | Y | n | |
| 6. | Nikon D60 | optical | n | 2.5 / 230 | fixed | n | 1/4000s | 3.0/s | Y | n | |
| 7. | Nikon D3000 | optical | n | 3.0 / 230 | fixed | n | 1/4000s | 3.0/s | Y | n | |
| 8. | Nikon D3200 | optical | n | 3.0 / 921 | fixed | n | 1/4000s | 4.0/s | Y | n | |
| 9. | Nikon D5000 | optical | n | 2.7 / 230 | full-flex | n | 1/4000s | 4.0/s | Y | n | |
| 10. | Nikon D5100 | optical | n | 3.0 / 921 | swivel | n | 1/4000s | 4.0/s | Y | n | |
| 11. | Nikon D7000 | optical | Y | 3.0 / 921 | fixed | n | 1/8000s | 6.0/s | Y | n | |
| 12. | Pentax K-3 | optical | Y | 3.2 / 1037 | fixed | n | 1/8000s | 8.3/s | Y | Y | |
| 13. | Pentax K-3 II | optical | Y | 3.2 / 1037 | fixed | n | 1/8000s | 8.3/s | n | Y | |
| 14. | Pentax K-70 | optical | n | 3.0 / 921 | swivel | n | 1/6000s | 6.0/s | Y | Y | |
| 15. | Pentax KP | optical | n | 3.0 / 921 | tilting | n | 1/6000s | 7.0/s | Y | Y | |
| 16. | Sony NEX-5N | optional | n | 3.0 / 920 | tilting | Y | 1/4000s | 10.0/s | n | n | |
| 17. | Sony NEX-C3 | optional | n | 3.0 / 920 | tilting | n | 1/4000s | 5.5/s | n | n | |
| Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one. | |||||||||||
One difference between the cameras concerns the presence of an on-board flash. The D3100 has one, while the K-3 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 Pentax K-3 III 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.
Concerning the storage of imaging data, both the D3100 and the K-3 III write their files to SDXC cards. The K-3 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 K-3 III supports UHS-II cards on its first slot and UHS-I on its second one, while the D3100 cannot take advantage of Ultra High Speed SD cards.
Connectivity comparison
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 Pentax K-3 III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

| Camera Model |
Hotshoe Port |
Internal Mic / Speaker |
Microphone Port |
Headphone Port |
HDMI Port |
USB Port |
WiFi Support |
NFC Support |
Bluetooth Support |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Nikon D3100 | Y | mono / mono | - | - | mini | 2.0 | - | - | - | |
| 2. | Pentax K-3 III | Y | stereo / mono | Y | Y | micro | 3.2 | Y | - | Y | |
| 3. | Fujifilm X-H1 | Y | stereo / mono | Y | - | micro | 3.0 | Y | - | - | |
| 4. | Nikon D40 | Y | - / - | - | - | - | 2.0 | - | - | - | |
| 5. | Nikon D40X | Y | - / - | - | - | - | 2.0 | - | - | - | |
| 6. | Nikon D60 | Y | - / - | - | - | - | 2.0 | - | - | - | |
| 7. | Nikon D3000 | Y | - / - | - | - | - | 2.0 | - | - | - | |
| 8. | Nikon D3200 | Y | mono / mono | Y | - | mini | 2.0 | - | - | - | |
| 9. | Nikon D5000 | Y | mono / mono | - | - | mini | 2.0 | - | - | - | |
| 10. | Nikon D5100 | Y | mono / mono | Y | - | mini | 2.0 | - | - | - | |
| 11. | Nikon D7000 | Y | mono / mono | Y | - | mini | 2.0 | - | - | - | |
| 12. | Pentax K-3 | Y | mono / mono | Y | Y | mini | 3.0 | - | - | - | |
| 13. | Pentax K-3 II | Y | mono / mono | Y | Y | mini | 3.0 | - | - | - | |
| 14. | Pentax K-70 | Y | stereo / mono | Y | - | mini | 2.0 | Y | - | - | |
| 15. | Pentax KP | Y | stereo / mono | Y | - | - | 2.0 | Y | - | - | |
| 16. | Sony NEX-5N | Y | stereo / mono | - | - | mini | 2.0 | - | - | - | |
| 17. | Sony NEX-C3 | Y | stereo / mono | - | - | mini | 2.0 | - | - | - |
It is notable that the K-3 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.
Studio photographers will appreciate that the Pentax K-3 III (unlike the D3100) 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 K-3 III has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.
The K-3 III is a recent model that features in the current product line-up of Pentax. 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 features and operation of the D3100 and K-3 III can be found, respectively, in the Nikon D3100 Manual (free pdf) or the online Pentax K-3 III Manual.
Review summary
So what is the bottom line? Is the Nikon D3100 better than the Pentax K-3 III or vice versa? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Nikon D3100:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- More compact: Is smaller (124x96mm vs 135x104mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 315g or 38 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 (70 percent cheaper at launch).
- More heavily discounted: Has been available for much longer (launched in August 2010).

Arguments in favor of the Pentax K-3 III:
- More detail: Has more megapixels (25.6 vs 14.2MP), which boosts linear resolution by 34%.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- High quality composites: Can combine several shots after pixel-shifting its sensor.
- Better video: Provides higher definition movie capture (4K/30p 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 complete view: Has a viewfinder with a larger field of view (100% vs 95%).
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.70x vs 0.53x).
- Easier setting verification: Features a control panel on top to check shooting parameters.
- Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
- More detailed LCD: Has a higher resolution rear screen (1620k vs 230k dots).
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (12 vs 3 flaps/sec) to capture the decisive moment.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- Longer lasting: Gets more shots (800 versus 550) out of a single battery charge.
- 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.
- 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.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- 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 and UHS-I) SDXC cards.
- More modern: Reflects 10 years and 7 months of technical progress since the D3100 launch.
If the count of relative strengths (bullet points above) is taken as a measure, the K-3 III is the clear winner of the contest (26 : 6 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. 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 Pentax K-3 III 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 D3100 and the K-3 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.
Expert reviews
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], digitalcameraworld [DCW], 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.

| Camera Model |
AP score |
CL score |
DCW score |
DPR score |
EPZ score |
PB score |
Camera Launch |
Launch Price |
Street Price |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Nikon D3100 | 5/5 | + + | .. | 72/100 | 4.5/5 | 4.5/5 | Aug 2010 | US$ 599 | ebay.com | |
| 2. | Pentax K-3 III | 4/5 | .. | 3/5 | .. | 4.5/5 | .. | Mar 2021 | US$ 1 999 | amazon.com | |
| 3. | Fujifilm X-H1 | .. | + | 5/5 | 86/100 | 4.5/5 | 4.5/5 | Feb 2018 | US$ 1 899 | ebay.com | |
| 4. | Nikon D40 | .. | 81/100 | .. | + + | o | 4.5/5 | Nov 2006 | US$ 499 | ebay.com | |
| 5. | Nikon D40X | .. | 79/100 | .. | + + | 4/5 | 4/5 | Mar 2007 | US$ 729 | ebay.com | |
| 6. | Nikon D60 | .. | 80/100 | .. | + + | 4/5 | 4.5/5 | Jan 2008 | US$ 629 | ebay.com | |
| 7. | Nikon D3000 | .. | + | .. | 72/100 | 4/5 | 4.5/5 | Jul 2009 | US$ 599 | ebay.com | |
| 8. | Nikon D3200 | 5/5 | + + | .. | 73/100 | 4.5/5 | 4.5/5 | Apr 2012 | US$ 599 | ebay.com | |
| 9. | Nikon D5000 | .. | + + | .. | 75/100 | 4/5 | 4.5/5 | Apr 2009 | US$ 749 | ebay.com | |
| 10. | Nikon D5100 | 5/5 | + + | .. | 76/100 | 4.5/5 | 4.5/5 | Apr 2011 | US$ 749 | ebay.com | |
| 11. | Nikon D7000 | 4/5 | .. | .. | 80/100 | 4.5/5 | 4.5/5 | Sep 2010 | US$ 1 499 | ebay.com | |
| 12. | Pentax K-3 | 4/5 | .. | .. | 83/100 | 5/5 | 5/5 | Oct 2013 | US$ 1 299 | ebay.com | |
| 13. | Pentax K-3 II | 4.5/5 | .. | .. | .. | 5/5 | 5/5 | Apr 2015 | US$ 1 099 | ebay.com | |
| 14. | Pentax K-70 | 4.5/5 | .. | 4/5 | 79/100 | 4.5/5 | 4.5/5 | Jun 2016 | US$ 649 | ebay.com | |
| 15. | Pentax KP | 4/5 | .. | 3/5 | 82/100 | 5/5 | 4.5/5 | Jan 2017 | US$ 1 099 | ebay.com | |
| 16. | Sony NEX-5N | 3/5 | + + | .. | 79/100 | 4.5/5 | 4.5/5 | Aug 2011 | US$ 699 | ebay.com | |
| 17. | Sony NEX-C3 | 3/5 | + + | .. | 74/100 | 4.5/5 | 4/5 | Jun 2011 | US$ 599 | ebay.com | |
| Note: (+ +) 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. A score, therefore, has to be seen in close connection to the price and market introduction time 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.

Check D3100 offers at
ebay.com

Check K-3 III price at
amazon.com
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.
- Canon 30D vs Nikon D3100
- Canon 5DS vs Nikon D3100
- Canon 6D vs Nikon D3100
- Canon 850D vs Pentax K-3 III
- Canon M6 vs Pentax K-3 III
- Fujifilm X-H2S vs Pentax K-3 III
- Nikon 1 V1 vs Nikon D3100
- Nikon D3000 vs Nikon D3100
- Nikon D3100 vs Olympus TG-4
- Panasonic FT7 vs Pentax K-3 III
- Panasonic TZ200 vs Pentax K-3 III
- Pentax K-3 III vs Sony A7R III
Specifications: Nikon D3100 vs Pentax K-3 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 | Pentax K-3 III |
|---|---|---|
| Camera Type | Digital single lens reflex | Digital single lens reflex |
| Camera Lens | Nikon F mount lenses | Pentax K mount lenses |
| Launch Date | August 2010 | March 2021 |
| Launch Price | USD 599 | USD 1,999 |
| Sensor Specs | Nikon D3100 | Pentax K-3 III |
| Sensor Technology | CMOS | CMOS |
| Sensor Format | APS-C Sensor | APS-C Sensor |
| Sensor Size | 23.1 x 15.4 mm | 23.3 x 15.5 mm |
| Sensor Area | 355.74 mm2 | 361.15 mm2 |
| Sensor Diagonal | 27.8 mm | 28 mm |
| Crop Factor | 1.5x | 1.5x |
| Sensor Resolution | 14.2 Megapixels | 25.6 Megapixels |
| Image Resolution | 4608 x 3072 pixels | 6192 x 4128 pixels |
| Pixel Pitch | 5.01 μm | 3.76 μm |
| Pixel Density | 3.98 MP/cm2 | 7.08 MP/cm2 |
| Moiré control | Anti-Alias filter | no AA filter |
| Movie Capability | 1080/24p Video | 4K/30p Video |
| ISO Setting | 100 - 3,200 ISO | 100 - 160,000 ISO |
| ISO Boost | 100 - 12,800 ISO | no Enhancement |
| Image Processor | EXPEED 2 | PRIME V |
| DXO Sensor Quality (score) | 67 | .. |
| DXO Color Depth (bits) | 22.5 | .. |
| DXO Dynamic Range (EV) | 11.3 | .. |
| DXO Low Light (ISO) | 919 | .. |
| Screen Specs | Nikon D3100 | Pentax K-3 III |
| Viewfinder Type | Optical viewfinder | Optical viewfinder |
| Viewfinder Field of View | 95% | 100% |
| Viewfinder Magnification | 0.53x | 0.70x |
| Top-Level Screen | no Top Display | Control Panel |
| LCD Framing | Live View | Live View |
| Rear LCD Size | 3.0inch | 3.2inch |
| LCD Resolution | 230k dots | 1620k dots |
| LCD Attachment | Fixed screen | Fixed screen |
| Touch Input | no Touchscreen | Touchscreen |
| Shooting Specs | Nikon D3100 | Pentax K-3 III |
| 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 | 3 shutter flaps/s | 12 shutter flaps/s |
| Shutter Life Expectancy | 100 000 actuations | 200 000 actuations |
| Time-Lapse Photography | no Intervalometer | Intervalometer built-in |
| Image Stabilization | Lens stabilization only | In-body stabilization |
| Fill Flash | Built-in Flash | no On-Board Flash |
| Storage Medium | SDXC cards | SDXC cards |
| Single or Dual Card Slots | Single card slot | Dual card slots |
| UHS card support | no | Single UHS-II |
| Connectivity Specs | Nikon D3100 | Pentax K-3 III |
| External Flash | Hotshoe | Hotshoe |
| Studio Flash | no PC Sync | PC Sync socket |
| USB Connector | USB 2.0 | USB 3.2 |
| HDMI Port | mini HDMI | micro 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 |
| Geotagging | no internal GPS | GPS built-in |
| Body Specs | Nikon D3100 | Pentax K-3 III |
| Environmental Sealing | not weather sealed | Weathersealed body |
| Battery Type | Nikon EN-EL14 | Pentax D-LI90 |
| Battery Life (CIPA) | 550 shots per charge | 800 shots per charge |
| Body Dimensions |
124 x 96 x 75 mm (4.9 x 3.8 x 3.0 in) |
135 x 104 x 74 mm (5.3 x 4.1 x 2.9 in) |
| Camera Weight | 505 g (17.8 oz) | 820 g (28.9 oz) |

Check D3100 offers at
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Check K-3 III price at
amazon.com
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