Canon G1 X Mark III vs Pentax 645D
The Canon PowerShot G1 X Mark III and the Pentax 645D are two digital cameras that were revealed to the public, respectively, in October 2017 and March 2010. The G1X Mark III is a fixed lens compact, while the 645D is a DSLR. The cameras are based on an APS-C (G1X Mark III) and a medium format (645D) sensor. The Canon has a resolution of 24 megapixels, whereas the Pentax provides 39.5 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 Canon PowerShot G1 X Mark III and the Pentax 645D? 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 Canon G1 X Mark III and the Pentax 645D 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 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 Pentax 645D is considerably larger (103 percent) than the Canon G1 X Mark III. In this context, it is worth noting that both cameras are splash and dust-proof and can, hence, be used in inclement weather conditions or harsh environments.
The above size and weight comparisons are to some extent incomplete and possibly misleading, as the G1X Mark III has a lens built in, whereas the 645D is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.
The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.
|1.||Canon G1 X Mark III||115 mm||78 mm||51 mm||399 g||200||Y||Oct 2017||1,299|
|2.||Pentax 645D||156 mm||117 mm||119 mm||1480 g||800||Y||Mar 2010||9,995|
|3.||Canon 6D Mark II||144 mm||111 mm||75 mm||765 g||1200||Y||Jun 2017||1,999|
|4.||Canon 80D||139 mm||105 mm||79 mm||730 g||960||Y||Feb 2016||1,199|
|5.||Canon SX540||120 mm||82 mm||92 mm||442 g||205||n||Jan 2016||399|
|6.||Canon 1D X||158 mm||168 mm||83 mm||1551 g||1120||Y||Oct 2011||6,799|
|7.||Canon 1D Mark IV||156 mm||157 mm||80 mm||1230 g||1500||Y||Oct 2009||4,999|
|8.||Fujifilm X100V||128 mm||75 mm||53 mm||478 g||420||Y||Feb 2020||1,399|
|9.||Fujifilm X-T3||133 mm||93 mm||59 mm||539 g||390||Y||Sep 2018||1,499|
|10.||Fujifilm X100F||127 mm||75 mm||52 mm||469 g||390||n||Jan 2017||1,299|
|11.||Leica S Typ 006||160 mm||120 mm||80 mm||1260 g||..||Y||Sep 2012||21,950|
|12.||Nikon D7500||136 mm||104 mm||73 mm||720 g||950||Y||Apr 2017||1,299|
|13.||Nikon D3S||160 mm||157 mm||88 mm||1240 g||4200||Y||Oct 2009||5,199|
|14.||Pentax 645Z||156 mm||117 mm||123 mm||1550 g||650||Y||Apr 2014||8,499|
|15.||Sony A6300||120 mm||67 mm||49 mm||404 g||400||Y||Feb 2016||999|
|16.||Sony A6500||120 mm||67 mm||53 mm||453 g||350||Y||Oct 2016||1,399|
|17.||Sony RX10 III||133 mm||94 mm||127 mm||1051 g||420||Y||Mar 2016||1,499|
|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 G1X Mark III was launched at a lower price than the 645D, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.
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 tend to be more expensive and lead to bigger and heavier cameras and lenses.
Of the two cameras under consideration, the Canon G1 X Mark III features an APS-C sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 337 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 0.79. The sensor in the G1X Mark III has a native 3:2 aspect ratio, while the one in the 645D offers a 4:3 aspect.
With 39.5MP, the 645D offers a higher resolution than the G1X Mark III (24MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 3.72μm for the G1X Mark III) due to its larger sensor. However, the G1X Mark III is a much more recent model (by 7 years and 7 months) than the 645D, 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 645D has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the Pentax 645D implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 645D for good quality output (200 dots per inch) amounts to 36.3 x 27.2 inches or 92.3 x 69.1 cm, for very good quality (250 dpi) 29.1 x 21.8 inches or 73.8 x 55.3 cm, and for excellent quality (300 dpi) 24.2 x 18.1 inches or 61.5 x 46.1 cm. The corresponding values for the Canon G1 X Mark III are 30 x 20 inches or 76.2 x 50.8 cm for good quality, 24 x 16 inches or 61 x 40.6 cm for very good quality, and 20 x 13.3 inches or 50.8 x 33.9 cm for excellent quality prints.
The G1X Mark III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
The Canon PowerShot G1 X Mark III has a native sensitivity range from ISO 100 to ISO 25600. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).
Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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. 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 |
|1.||Canon G1 X Mark III||APS-C||24.0||6000||4000||1080/60p||..||..||..||..|
|2.||Pentax 645D||Medium Format||39.5||7264||5440||none||24.6||12.6||1262||82|
|3.||Canon 6D Mark II||Full Frame||26.0||6240||4160||1080/60p||24.4||11.9||2862||85|
|6.||Canon 1D X||Full Frame||17.9||5184||3456||1080/30p||23.8||11.8||2786||82|
|7.||Canon 1D Mark IV||APS-H||16.0||4896||3264||1080/30p||22.8||12.0||1320||74|
|11.||Leica S Typ 006||Medium Format||37.5||7500||5000||none||23.9||12.2||824||76|
|13.||Nikon D3S||Full Frame||12.1||4256||2832||720/24p||23.5||12.0||3253||82|
|14.||Pentax 645Z||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101|
|17.||Sony RX10 III||1-inch||20.0||5472||3648||4K/30p||23.1||12.6||472||70|
Many modern cameras are not only capable of taking still images, but can also record movies. The G1X Mark III indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the G1X Mark III can use is 1080/60p.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the G1X Mark III has an electronic viewfinder (2360k dots), while the 645D 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 table below summarizes some of the other core capabilities of the Canon G1 X Mark III and Pentax 645D in connection with corresponding information for a sample of similar cameras.
|1.||Canon G1 X Mark III||2360||n||3.0||1040||swivel||Y||1/2000s||9.0||Y||Y|
|3.||Canon 6D Mark II||optical||Y||3.0||1040||swivel||Y||1/4000s||6.5||n||n|
|6.||Canon 1D X||optical||Y||3.2||1040||fixed||n||1/8000s||14.0||n||n|
|7.||Canon 1D Mark IV||optical||Y||3.0||920||fixed||n||1/8000s||10.0||n||n|
|11.||Leica S Typ 006||optical||Y||3.0||922||fixed||n||1/4000s||1.5||n||n|
|17.||Sony RX10 III||2359||Y||3.0||1229||tilting||n||1/2000s||14.0||Y||Y|
One difference between the cameras concerns the presence of an on-board flash. The G1X Mark III has one, while the 645D does not. While the built-in flash of the G1X Mark III is not very powerful, it can at times be useful as a fill-in light.The G1X Mark III has an articulated LCD that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in snapping selfies. In contrast, the 645D does not have a selfie-screen.
The Canon G1 X Mark III and the Pentax 645D 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 G1X Mark III and the 645D write their files to SDXC cards. The 645D features dual card slots, which can be very useful in case a memory card fails. In contrast, the G1X Mark III only has one slot. The G1X Mark III supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the 645D 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 Canon PowerShot G1 X Mark III and Pentax 645D and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|1.||Canon G1 X Mark III||Y||stereo||mono||-||-||micro||2.0||Y||Y||Y|
|3.||Canon 6D Mark II||Y||stereo||mono||Y||-||mini||2.0||Y||Y||Y|
|6.||Canon 1D X||Y||mono||-||Y||-||mini||2.0||-||-||-|
|7.||Canon 1D Mark IV||Y||stereo||-||Y||-||mini||2.0||-||-||-|
|11.||Leica S Typ 006||Y||-||-||-||-||mini||2.0||-||-||-|
|17.||Sony RX10 III||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the G1X Mark III offers wifi support, while the 645D does not. Wifi can be a very convenient means to transfer image data to an off-camera location.
Studio photographers will appreciate that the Pentax 645D (unlike the G1X Mark III) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
The G1X Mark III is a recent model that features in the current product line-up of Canon. In contrast, the 645D has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the 645D was succeeded by the Pentax 645Z. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Canon and Pentax websites.
So how do things add up? Is there a clear favorite between the Canon G1 X Mark III and the Pentax 645D? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.
Advantages of the Canon PowerShot G1 X Mark III:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Broader imaging potential: Can record not only still images but also 1080/60p movies.
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- More framing info: Has an electronic viewfinder that displays shooting data.
- More detailed LCD: Has a higher resolution rear screen (1040k vs 921k dots).
- More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
- Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster burst: Shoots at higher frequency (9 vs 1.1 flaps/sec) to capture the decisive moment.
- Ready to shoot: Comes with a built-in lens, while the 645D requires a separate lens.
- More compact: Is smaller (115x78mm vs 156x117mm) and thus needs less room in the bag.
- Less heavy: Is lighter even though it comes with a built-in lens (unlike the 645D).
- Sharper images: Has hand-shake reducing image stabilization built-in.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
- Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
- Easier wireless transfer: Supports Bluetooth for image sharing without cables.
- Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
- More affordable: Was introduced at a lower price, despite coming with a built-in lens.
- More modern: Reflects 7 years and 7 months of technical progress since the 645D launch.
Reasons to prefer the Pentax 645D:
- More detail: Has more megapixels (39.5 vs 24MP), which boosts linear resolution by 26%.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Easier setting verification: Features a control panel on top to check shooting parameters.
- Faster shutter: Has higher mechanical shutter speed (1/4000s vs 1/2000s) to freeze action.
- More flexible: Makes it possible to change lenses and thus to use specialty optics.
- Longer lasting: Gets more shots (800 versus 200) out of a single battery charge.
- 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 around for much longer (launched in March 2010).
If the count of relative strengths (bullet points above) is taken as a measure, the G1X Mark III is the clear winner of the match-up (20 : 10 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 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 Canon G1 X Mark III and the Pentax 645D place the cameras among the top in their class? Find out in the latest Best Travel-Zoom Camera and Best DSLR 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 G1X Mark III and the 645D 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 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 (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.||Canon G1 X Mark III||5/5||+||79/100||4.5/5||4.5/5||Oct 2017||1,299|
|2.||Pentax 645D||5/5||..||..||..||..||Mar 2010||9,995|
|3.||Canon 6D Mark II||4/5||+||80/100||4.5/5||4/5||Jun 2017||1,999|
|4.||Canon 80D||4/5||+ +||84/100||4.5/5||4.5/5||Feb 2016||1,199|
|5.||Canon SX540||..||..||..||..||..||Jan 2016||399|
|6.||Canon 1D X||5/5||..||..||4.5/5||4.5/5||Oct 2011||6,799|
|7.||Canon 1D Mark IV||5/5||..||89/100||..||..||Oct 2009||4,999|
|8.||Fujifilm X100V||5/5||+ +||86/100||5/5||4.5/5||Feb 2020||1,399|
|9.||Fujifilm X-T3||5/5||+ +||88/100||5/5||5/5||Sep 2018||1,499|
|10.||Fujifilm X100F||5/5||+||83/100||4.5/5||4.5/5||Jan 2017||1,299|
|11.||Leica S Typ 006||..||..||..||..||..||Sep 2012||21,950|
|12.||Nikon D7500||4.5/5||+ +||86/100||5/5||4.5/5||Apr 2017||1,299|
|13.||Nikon D3S||5/5||..||89/100||4.5/5||5/5||Oct 2009||5,199|
|14.||Pentax 645Z||5/5||..||..||4.5/5||5/5||Apr 2014||8,499|
|15.||Sony A6300||4.5/5||+||85/100||5/5||5/5||Feb 2016||999|
|16.||Sony A6500||5/5||+ +||85/100||4.5/5||4.5/5||Oct 2016||1,399|
|17.||Sony RX10 III||5/5||+||84/100||4.5/5||4.5/5||Mar 2016||1,499|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. 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. 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.
Specifications: Canon G1 X Mark III vs Pentax 645D
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||Canon G1 X Mark III||Pentax 645D|
|Camera Type||Fixed lens compact camera||Digital single lens reflex|
|Camera Lens||24-72mm f/2.8-5.6||Pentax 645 mount lenses|
|Launch Date||October 2017||March 2010|
|Launch Price||USD 1,299||USD 9,995|
|Sensor Specs||Canon G1 X Mark III||Pentax 645D|
|Sensor Format||APS-C Sensor||Medium Format Sensor|
|Sensor Size||22.3 x 14.9 mm||44.0 x 33.0 mm|
|Sensor Area||332.27 mm2||1452 mm2|
|Sensor Diagonal||26.8 mm||55 mm|
|Sensor Resolution||24 Megapixels||39.5 Megapixels|
|Image Resolution||6000 x 4000 pixels||7264 x 5440 pixels|
|Pixel Pitch||3.72 μm||6.06 μm|
|Pixel Density||7.22 MP/cm2||2.72 MP/cm2|
|Moiré control||Anti-Alias filter||no AA filter|
|Movie Capability||1080/60p Video||no Video|
|ISO Setting||100 - 25,600 ISO||100 - 1,600 ISO|
|Image Processor||DIGIC 7||PRIME II|
|DXO Sensor Quality (score)||..||82|
|DXO Color Depth (bits)||..||24.6|
|DXO Dynamic Range (EV)||..||12.6|
|DXO Low Light (ISO)||..||1262|
|Screen Specs||Canon G1 X Mark III||Pentax 645D|
|Viewfinder Type||Electronic viewfinder||Optical viewfinder|
|Viewfinder Field of View||100%||98%|
|Viewfinder Resolution||2360k dots|
|Top-Level Screen||no Top Display||Control Panel|
|LCD Framing||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1040k dots||921k dots|
|LCD Attachment||Swivel screen||Fixed screen|
|Touch Input||Touchscreen||no Touchscreen|
|Shooting Specs||Canon G1 X Mark III||Pentax 645D|
|Focus System||On-Sensor Phase-detect||Phase-detect AF|
|Manual Focusing Aid||Focus Peaking||no Peaking Feature|
|Continuous Shooting||9 shutter flaps/s||1.1 shutter flaps/s|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||UHS-I||no|
|Connectivity Specs||Canon G1 X Mark III||Pentax 645D|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||micro HDMI||no HDMI|
|Wifi Support||Wifi built-in||no Wifi|
|Near-Field Communication||NFC built-in||no NFC|
|Bluetooth Support||Bluetooth built-in||no Bluetooth|
|Body Specs||Canon G1 X Mark III||Pentax 645D|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||200 shots per charge||800 shots per charge|
115 x 78 x 51 mm
(4.5 x 3.1 x 2.0 in)
156 x 117 x 119 mm
(6.1 x 4.6 x 4.7 in)
|Camera Weight||399 g (14.1 oz)||1480 g (52.2 oz)|
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