Pentax K-3 vs Ricoh GR III
The Pentax K-3 and the Ricoh GR III are two digital cameras that were announced, respectively, in October 2013 and February 2019. The K-3 is a DSLR, while the GR III is a fixed lens compact. Both cameras are equipped with an APS-C sensor. The Pentax has a resolution of 24.1 megapixels, whereas the Ricoh provides 24 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
|Pentax K-3||Ricoh GR III|
|Digital single lens reflex||Fixed lens compact camera|
|Pentax K mount lenses||28mm f/2.8|
|24.1 MP, APS-C Sensor||24 MP, APS-C Sensor|
|1080/60i Video||1080/60p Video|
|ISO 100-51200||ISO 100-102400|
|Optical viewfinder||Viewfinder optional|
|3.2" LCD, 1037k dots||3.0" LCD, 1037k dots|
|Fixed screen (not touch-sensitive)||Fixed touchscreen|
|8.3 shutter flaps per second||4 shutter flaps per second|
|In-body stabilization||In-body stabilization|
|Weathersealed body||Not weather sealed|
|560 shots per battery charge||200 shots per battery charge|
|131 x 100 x 77 mm, 800 g||109 x 62 x 33 mm, 257 g|
Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-3 and the Ricoh GR 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.
The physical size and weight of the Pentax K-3 and the Ricoh GR III are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth dimensions are rounded to the nearest millimeter.
The K-3 can be obtained in two different colors (black, silver), while the GR 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 Ricoh GR III is considerably smaller (48 percent) than the Pentax K-3. It is worth mentioning in this context that the K-3 is splash and dust resistant, while the GR III does not feature any corresponding weather-sealing.
The above size and weight comparisons are to some extent incomplete and possibly misleading, as the GR III has a lens built in, whereas the K-3 is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.
The power pack in the GR 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, just select a new right or left comparator from among the camera models in the table. Alternatively, you can also move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.
|Pentax K-3»||5.2 in||3.9 in||3.0 in||28.2 oz||560||Y||Oct 2013||1,299||Pentax K-3|
|Ricoh GR III«||4.3 in||2.4 in||1.3 in||9.1 oz||200||n||Feb 2019||899||Ricoh GR III|
|Canon G7 X Mark III« »||4.1 in||2.4 in||1.6 in||10.7 oz||235||n||Jul 2019||749||Canon G7 X Mark III|
|Canon 70D« »||5.5 in||4.1 in||3.1 in||26.6 oz||920||Y||Jul 2013||1,199||Canon 70D|
|Fujifilm XF10« »||4.4 in||2.5 in||1.6 in||9.8 oz||330||n||Jul 2018||499||Fujifilm XF10|
|Nikon D7200« »||5.4 in||4.2 in||3.0 in||27.0 oz||1110||Y||Mar 2015||1,199||Nikon D7200|
|Nikon D7100« »||5.4 in||4.2 in||3.0 in||27.0 oz||950||Y||Feb 2013||1,199||Nikon D7100|
|Panasonic ZS200« »||4.4 in||2.6 in||1.8 in||12.0 oz||370||n||Feb 2018||799||Panasonic ZS200|
|Pentax KP« »||5.2 in||4.0 in||3.0 in||24.8 oz||390||Y||Jan 2017||1,099||Pentax KP|
|Pentax K-70« »||5.0 in||3.7 in||2.9 in||24.3 oz||410||Y||Jun 2016||649||Pentax K-70|
|Pentax K-3 II« »||5.2 in||3.9 in||3.0 in||28.2 oz||720||Y||Apr 2015||1,099||Pentax K-3 II|
|Pentax K-5« »||5.2 in||3.8 in||2.9 in||26.8 oz||740||Y||Sep 2010||1,099||Pentax K-5|
|Ricoh GR II« »||4.6 in||2.5 in||1.4 in||8.9 oz||320||n||Jun 2015||699||Ricoh GR II|
|Ricoh GR« »||4.6 in||2.4 in||1.4 in||8.6 oz||290||n||Apr 2013||799||Ricoh GR|
|Sony A6500« »||4.7 in||2.6 in||2.1 in||16.0 oz||350||Y||Oct 2016||1,399||Sony A6500|
|Sony A99« »||5.8 in||4.4 in||3.1 in||28.6 oz||500||Y||Sep 2012||2,799||Sony A99|
|Sony A77« »||5.6 in||4.1 in||3.2 in||25.8 oz||470||Y||Aug 2011||1,399||Sony A77|
|Note: Measurements and pricing do not include easily detachable parts, such as interchangeable lenses or optional viewfinders.|
Any camera decision will naturally be influenced heavily by the price. 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 GR III was launched at a lower price than the K-3, despite having a lens built in. 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.
The imaging sensor is at the core of digital cameras and its size is one of the main determining factors of image quality. A large sensor will 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.
Both cameras under consideration feature an APS-C sensor and have a format factor (sometimes also referred to as "crop factor") of 1.5. Within the spectrum of camera sensors, this places the review cameras among the medium-sized sensor cameras that aim to strike a balance between image quality and portability. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.
Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors.
While the two cameras under review share the same sensor size, the K-3 offers a slightly higher resolution of 24.1 megapixels, compared with 24 MP of the GR III. This megapixels advantage translates into a 0.3 percent gain in linear resolution. On the other hand, these sensor specs imply that the K-3 has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.90μm versus 3.91μm for the GR III). Moreover, it should be noted that the GR III is much more recent (by 5 years and 4 months) than the K-3, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of individual pixels. Coming back to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.
The GR III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
The Pentax K-3 has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Ricoh GR III are ISO 100 to ISO 102400 (no boost).
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 table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.
|Pentax K-3||APS-C||24.1||6016||4000||1080/60i||23.7||13.4||1216||80||Pentax K-3|
|Ricoh GR III||APS-C||24.0||6000||4000||1080/60p||..||..||..||..||Ricoh GR III|
|Canon G7 X Mark III||1-inch||20.0||5472||3648||4K/30p||..||..||..||..||Canon G7 X Mark III|
|Canon 70D||APS-C||20.0||5472||3648||1080/30p||22.5||11.6||926||68||Canon 70D|
|Fujifilm XF10||APS-C||24.0||6000||4000||4K/15p||..||..||..||..||Fujifilm XF10|
|Nikon D7200||APS-C||24.0||6000||4000||1080/60p||24.5||14.6||1333||87||Nikon D7200|
|Nikon D7100||APS-C||24.0||6000||4000||1080/60p||24.2||13.7||1256||83||Nikon D7100|
|Panasonic ZS200||1-inch||20.0||5472||3648||4K/30p||..||..||..||..||Panasonic ZS200|
|Pentax KP||APS-C||24.1||6016||4000||1080/60i||..||..||..||..||Pentax KP|
|Pentax K-70||APS-C||24.0||6000||4000||1080/60i||..||..||..||..||Pentax K-70|
|Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80||Pentax K-3 II|
|Pentax K-5||APS-C||16.1||4928||3264||1080/25p||23.7||14.1||1162||82||Pentax K-5|
|Ricoh GR II||APS-C||16.1||4928||3264||1080/30p||23.6||13.7||1078||80||Ricoh GR II|
|Ricoh GR||APS-C||16.1||4928||3264||1080/30p||23.6||13.5||972||78||Ricoh GR|
|Sony A6500||APS-C||24.0||6000||4000||4K/30p||24.5||13.7||1405||85||Sony A6500|
|Sony A99||Full Frame||24.0||6000||4000||1080/60p||25.0||14.0||1555||89||Sony A99|
|Sony A77||APS-C||24.0||6000||4000||1080/60p||24.0||13.2||801||78||Sony A77|
Many modern cameras are not only capable of taking still images, but also of capturing video footage. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the GR III provides a faster frame rate than the K-3. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the K-3 has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the GR III relies on live view and the rear LCD for framing. That said, the GR III can be equipped with an optional viewfinder – the GV-1. The adjacent table lists some of the other core features of the Pentax K-3 and Ricoh GR III along with similar information for a selection of comparators.
|Pentax K-3||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||Y||Y||Pentax K-3|
|Ricoh GR III||optional||n||3.0||1037||fixed||Y||1/4000s||4.0||n||Y||Ricoh GR III|
|Canon G7 X Mark III||none||n||3.0||1040||tilting||Y||1/2000s||30||Y||Y||Canon G7 X Mark III|
|Canon 70D||optical||Y||3.0||1040||swivel||Y||1/8000s||7.0||Y||n||Canon 70D|
|Fujifilm XF10||none||n||3.0||1040||fixed||Y||1/4000s||6.0||Y||n||Fujifilm XF10|
|Nikon D7200||optical||Y||3.2||1229||fixed||n||1/8000s||6.0||Y||n||Nikon D7200|
|Nikon D7100||optical||Y||3.2||1229||fixed||n||1/8000s||6.0||Y||n||Nikon D7100|
|Panasonic ZS200||2330||n||3.0||1240||fixed||Y||1/2000s||10.0||Y||Y||Panasonic ZS200|
|Pentax KP||optical||n||3.0||921||tilting||n||1/6000s||7.0||Y||Y||Pentax KP|
|Pentax K-70||optical||n||3.0||921||swivel||n||1/6000s||6.0||Y||Y||Pentax K-70|
|Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y||Pentax K-3 II|
|Pentax K-5||optical||Y||3.0||921||fixed||n||1/8000s||7.0||Y||Y||Pentax K-5|
|Ricoh GR II||optional||n||3.0||1230||fixed||n||1/4000s||4.0||Y||n||Ricoh GR II|
|Ricoh GR||optional||n||3.0||1230||fixed||n||1/4000s||4.0||Y||n||Ricoh GR|
|Sony A6500||2359||n||3.0||922||tilting||Y||1/4000s||11.0||Y||Y||Sony A6500|
|Sony A99||2359||Y||3.0||1229||full-flex||n||1/8000s||6.0||n||Y||Sony A99|
|Sony A77||2359||Y||3.0||921||full-flex||n||1/8000s||12.0||Y||Y||Sony A77|
One difference between the cameras concerns the presence of an on-board flash. The K-3 has one, while the GR III does not. While the built-in flash of the K-3 is not very powerful, it can at times be useful as a fill-in light.
The Pentax K-3 and the Ricoh GR III both have 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 K-3 and the GR III write their files to SDXC cards. The K-3 features dual card slots, which can be very useful in case a memory card fails. In contrast, the GR III only has one slot. 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 Pentax K-3 and Ricoh GR III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
|Pentax K-3||Y||mono||mono||Y||Y||mini||3.0||-||-||-||Pentax K-3|
|Ricoh GR III||Y||stereo||mono||-||-||none||3.0||Y||-||Y||Ricoh GR III|
|Canon G7 X Mark III||-||stereo||mono||Y||-||micro||3.1||Y||-||Y||Canon G7 X Mark III|
|Canon 70D||Y||stereo||mono||Y||-||mini||2.0||Y||-||-||Canon 70D|
|Fujifilm XF10||-||stereo||mono||Y||-||micro||2.0||Y||-||Y||Fujifilm XF10|
|Nikon D7200||Y||stereo||mono||Y||Y||mini||2.0||Y||Y||-||Nikon D7200|
|Nikon D7100||Y||stereo||mono||Y||Y||mini||2.0||-||-||-||Nikon D7100|
|Panasonic ZS200||-||stereo||mono||-||-||micro||2.0||Y||-||Y||Panasonic ZS200|
|Pentax KP||Y||stereo||mono||Y||-||none||2.0||Y||-||-||Pentax KP|
|Pentax K-70||Y||stereo||mono||Y||-||mini||2.0||Y||-||-||Pentax K-70|
|Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-||Pentax K-3 II|
|Pentax K-5||Y||stereo||mono||Y||-||mini||2.0||-||-||-||Pentax K-5|
|Ricoh GR II||Y||stereo||mono||-||-||micro||2.0||Y||Y||-||Ricoh GR II|
|Ricoh GR||Y||mono||mono||-||-||micro||2.0||-||-||-||Ricoh GR|
|Sony A6500||Y||stereo||mono||Y||-||micro||2.0||Y||Y||-||Sony A6500|
|Sony A99||Y||stereo||mono||Y||Y||mini||2.0||-||-||-||Sony A99|
|Sony A77||Y||stereo||mono||Y||-||mini||2.0||-||-||-||Sony A77|
It is notable that the K-3 has a microphone port, which is missing on the GR III. Such an external microphone input can help to substantially improve the quality of audio recordings when a good external microphone is used.
Studio photographers will appreciate that the Pentax K-3 (unlike the GR III) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
The GR III is a recent model that features in the current product line-up of Ricoh. In contrast, the K-3 has been discontinued (but it can be found pre-owned on eBay). As a replacement in the same line of cameras, the K-3 was succeeded by the Pentax K-3 II. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Pentax and Ricoh websites.
So what is the bottom line? Which of the two cameras – the Pentax K-3 or the Ricoh GR III – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.
Arguments in favor of the Pentax K-3:
- 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.
- Easier framing: Has an optical viewfinder for image composition and settings control.
- 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.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (8.3 vs 4 flaps/sec) to capture the decisive moment.
- More flexible: Can take a variety of interchangeable lenses, including specialty optics.
- Longer lasting: Can take more shots (560 versus 200) on a single battery charge.
- Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- 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.
- More heavily discounted: Has been available for much longer (launched in October 2013).
Advantages of the Ricoh GR III:
- Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- Ready to shoot: Comes with an integrated lens, while the K-3 requires a separate lens.
- More compact: Is smaller (109x62mm vs 131x100mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight even though it has a lens built in (unlike the K-3).
- Easier travel charging: Can be conveniently charged via its USB port.
- 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.
- More affordable: Was introduced at a lower price, despite coming with a built-in lens.
- More modern: Reflects 5 years and 4 months of technical progress since the K-3 launch.
If the number of relative strengths (bullet points above) is taken as a guide, the K-3 is the clear winner of the match-up (14 : 10 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 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 Pentax K-3 and the Ricoh GR III place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Prime Lens Compact Camera listings whether the two cameras rank among the cream of the crop.
In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the K-3 or the GR III 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 where reviews by experts come in. 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.
Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.
Other camera comparisons
Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.
- Canon 10D vs Pentax K-3 II
- Canon 1D X Mark II vs Ricoh GR III
- Canon SX710 vs Pentax K-3
- Fujifilm X-Pro2 vs Pentax K-3 II
- Leica TL vs Pentax K-3 II
- Nikon P7800 vs Pentax K-3 II
- Olympus E-30 vs Pentax K-3
- Olympus PEN-F vs Pentax K-3 II
- Olympus XZ-1 vs Pentax K-3
- Pentax K-3 II vs Sony NEX-6
- Ricoh GR III vs Sony HX99
- Ricoh GR III vs Sony RX1R
Specifications: Pentax K-3 vs Ricoh GR 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||Pentax K-3||Ricoh GR III|
|Camera Type||Digital single lens reflex||Fixed lens compact camera|
|Camera Lens||Pentax K mount lenses||28mm f/2.8|
|Launch Date||October 2013||February 2019|
|Launch Price||USD 1299||USD 899|
|Sensor Specs||Pentax K-3||Ricoh GR III|
|Sensor Format||APS-C Sensor||APS-C Sensor|
|Sensor Size||23.5 x 15.6 mm||23.5 x 15.6 mm|
|Sensor Area||366.6 mm2||366.6 mm2|
|Sensor Diagonal||28.2 mm||28.2 mm|
|Sensor Resolution||24.1 Megapixels||24 Megapixels|
|Image Resolution||6016 x 4000 pixels||6000 x 4000 pixels|
|Pixel Pitch||3.90 μm||3.91 μm|
|Pixel Density||6.56 MP/cm2||6.55 MP/cm2|
|Moiré control||no AA filter||no AA filter|
|Movie Capability||1080/60i Video||1080/60p Video|
|ISO Setting||100-51200 ISO||100-102400 ISO|
|Image Processor||PRIME III||GR Engine VI|
|DXO Sensor Quality (score)||80||..|
|DXO Color Depth (bits)||23.7||..|
|DXO Dynamic Range (EV)||13.4||..|
|DXO Low Light (ISO)||1216||..|
|Screen Specs||Pentax K-3||Ricoh GR III|
|Viewfinder Type||Optical viewfinder||Viewfinder optional|
|Viewfinder Field of View||100%|
|Top-Level Screen||Control Panel||no Top Display|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.2 inch||3.0 inch|
|LCD Resolution||1037k dots||1037k dots|
|LCD Attachment||Fixed screen||Fixed screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Pentax K-3||Ricoh GR III|
|Focus System||Phase-detect AF||On-Sensor Phase-detect|
|Manual Focusing Aid||Focus Peaking||No Peaking Feature|
|Continuous Shooting||8.3 shutter flaps/s||4 shutter flaps/s|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||SDXC cards|
|Second Storage Option||Dual card slots||Single card slot|
|UHS card support||UHS-I||UHS-I|
|Connectivity Specs||Pentax K-3||Ricoh GR III|
|Studio Flash||PC Sync socket||no PC Sync|
|USB Connector||USB 3.0||USB 3.0|
|HDMI Port||mini HDMI||no HDMI|
|Microphone Port||External MIC port||no MIC socket|
|Headphone Socket||Headphone port||no Headphone port|
|Wifi Support||no Wifi||Wifi built-in|
|Bluetooth Support||no Bluetooth||Bluetooth built-in|
|Body Specs||Pentax K-3||Ricoh GR III|
|Environmental Sealing||Weathersealed body||Not weather sealed|
|Battery Life (CIPA)||560 shots per charge||200 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
131 x 100 x 77 mm
(5.2 x 3.9 x 3.0 in)
109 x 62 x 33 mm
(4.3 x 2.4 x 1.3 in)
|Camera Weight||800 g (28.2 oz)||257 g (9.1 oz)|
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