Pentax 645D vs Sony RX1
The Pentax 645D and the Sony Cyber-shot DSC-RX1 are two digital cameras that were announced, respectively, in March 2010 and September 2012. The 645D is a DSLR, while the RX1 is a fixed lens compact. The cameras are based on a medium format (645D) and a full frame (RX1) sensor. The Pentax has a resolution of 39.5 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.
|Pentax 645D||Sony RX1|
|Digital single lens reflex||Fixed lens compact camera|
|Pentax 645 mount lenses||35mm f/2.0|
|39.5 MP, Medium Format Sensor||24 MP, Full Frame Sensor|
|no Video||1080/60p Video|
|ISO 100-1600||ISO 100-25600 (50-102400)|
|Optical viewfinder||Viewfinder optional|
|3.0" LCD, 921k dots||3.0" LCD, 1229k dots|
|Fixed screen (not touch-sensitive)||Fixed screen (not touch-sensitive)|
|1.1 shutter flaps per second||5 shutter flaps per second|
|Weathersealed body||Not weather sealed|
|800 shots per battery charge||270 shots per battery charge|
|156 x 117 x 119 mm, 1480 g||113 x 65 x 70 mm, 482 g|
Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax 645D and the Sony Cyber-shot DSC-RX1? 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 645D and the Sony RX1 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 RX1 is considerably smaller (60 percent) than the Pentax 645D. It is worth mentioning in this context that the 645D is splash and dust resistant, while the RX1 does not feature any corresponding weather-sealing.
The above size and weight comparisons are to some extent incomplete and possibly misleading, as the RX1 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.
Concerning battery life, the 645D gets 800 shots out of its D-LI90 battery, while the RX1 can take 270 images on a single charge of its NP-BX1 power pack. The power pack in the RX1 can be charged via the USB port, which can be very convenient when travelling.
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, just click on the right or left arrow next to the camera that you would like to inspect. Alternatively, you can also use the CAM-parator to select your camera combination among a larger number of options.
|Pentax 645D»||6.1 in||4.6 in||4.7 in||52.2 oz||800||Y||Mar 2010||9,995||Pentax 645D|
|Sony RX1«||4.4 in||2.6 in||2.8 in||17.0 oz||270||n||Sep 2012||2,799||Sony RX1|
|Canon 1D X Mark II« »||6.2 in||6.6 in||3.3 in||54.0 oz||1210||Y||Feb 2016||5,999||Canon 1D X Mark II|
|Canon 1D X« »||6.2 in||6.6 in||3.3 in||54.7 oz||1120||Y||Oct 2011||6,799||Canon 1D X|
|Canon 1D Mark IV« »||6.1 in||6.2 in||3.1 in||43.4 oz||1500||Y||Oct 2009||4,999||Canon 1D Mark IV|
|Leica S Typ 006« »||6.3 in||4.7 in||3.1 in||44.4 oz||..||Y||Sep 2012||21,950||Leica S Typ 006|
|Nikon D850« »||5.7 in||4.9 in||3.1 in||35.5 oz||1840||Y||Jul 2017||3,299||Nikon D850|
|Nikon D5« »||6.3 in||6.3 in||3.6 in||49.9 oz||3780||Y||Jan 2016||6,499||Nikon D5|
|Nikon D810« »||5.7 in||4.8 in||3.2 in||34.6 oz||1200||Y||Jun 2014||3,299||Nikon D810|
|Nikon D5300« »||4.9 in||3.9 in||3.0 in||16.9 oz||600||n||Oct 2013||799||Nikon D5300|
|Nikon D3S« »||6.3 in||6.2 in||3.5 in||43.7 oz||4200||Y||Oct 2009||5,199||Nikon D3S|
|Pentax 645Z« »||6.1 in||4.6 in||4.8 in||54.7 oz||650||Y||Apr 2014||8,499||Pentax 645Z|
|Sony RX1R II« »||4.4 in||2.6 in||2.8 in||17.9 oz||220||n||Oct 2015||3,299||Sony RX1R II|
|Sony A7R« »||5.0 in||3.7 in||1.9 in||16.4 oz||340||Y||Oct 2013||2,299||Sony A7R|
|Sony A3000« »||5.0 in||3.6 in||3.3 in||14.5 oz||470||n||Aug 2013||329||Sony A3000|
|Sony RX1R« »||4.4 in||2.6 in||2.8 in||17.0 oz||270||n||Jun 2013||2,799||Sony RX1R|
|Sony NEX-7« »||4.7 in||2.6 in||1.7 in||14.1 oz||430||n||Aug 2011||1,349||Sony NEX-7|
|Note: Measurements and pricing do not include easily detachable parts, such as interchangeable lenses or optional viewfinders.|
The price is, of course, an important factor in any camera decision. 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 RX1 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 associated with larger, more expensive camera bodies and lenses.
Of the two cameras under consideration, the Pentax 645D features a medium format sensor and the Sony RX1 a full frame sensor. The sensor area in the RX1 is 41 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 0.79 and 1.0. The sensor in the 645D has a native 4:3 aspect ratio, while the one in the RX1 offers a 3:2 aspect.
With 39.5MP, the 645D offers a higher resolution than the RX1 (24MP), but the 645D nevertheless has marginally larger individual pixels (pixel pitch of 6.06μm versus 5.96μm for the RX1) due to its larger sensor. However, the RX1 is a much more recent model (by 2 years and 6 months) than the 645D, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. 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 inch or 92.3 x 69.1 cm, for very good quality (250 dpi) 29.1 x 21.8 inch or 73.8 x 55.3 cm, and for excellent quality (300 dpi) 24.2 x 18.1 inch or 61.5 x 46.1 cm. The corresponding values for the Sony RX1 are 30 x 20 inch or 76.2 x 50.8 cm for good quality, 24 x 16 inch or 61 x 40.6 cm for very good quality, and 20 x 13.3 inch or 50.8 x 33.9 cm for excellent quality prints.
The Pentax 645D has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Sony Cyber-shot DSC-RX1 are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-102400.
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. Of the two cameras under consideration, the RX1 offers substantially better image quality than the 645D (overall score 11 points higher). The advantage is based on 0.5 bits higher color depth, 1.7 EV in additional dynamic range, and 1 stops in additional low light sensitivity. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
|Pentax 645D||Medium Format||39.5||7264||5440||none||24.6||12.6||1262||82||Pentax 645D|
|Sony RX1||Full Frame||24.0||6000||4000||1080/60p||25.1||14.3||2534||93||Sony RX1|
|Canon 1D X Mark II||Full Frame||20.0||5472||3648||4K/60p||24.1||13.5||3207||88||Canon 1D X Mark II|
|Canon 1D X||Full Frame||17.9||5184||3456||1080/30p||23.8||11.8||2786||82||Canon 1D X|
|Canon 1D Mark IV||APS-H||16.0||4896||3264||1080/30p||22.8||12.0||1320||74||Canon 1D Mark IV|
|Leica S Typ 006||Medium Format||37.5||7500||5000||none||23.9||12.2||824||76||Leica S Typ 006|
|Nikon D850||Full Frame||45.4||8256||5504||4K/30p||26.4||14.8||2660||100||Nikon D850|
|Nikon D5||Full Frame||20.7||5588||3712||4K/30p||25.1||12.3||2343||88||Nikon D5|
|Nikon D810||Full Frame||36.2||7360||4912||1080/60p||25.7||14.8||2853||97||Nikon D810|
|Nikon D5300||APS-C||24.0||6000||4000||1080/60p||24.0||13.9||1338||83||Nikon D5300|
|Nikon D3S||Full Frame||12.1||4256||2832||720/24p||23.5||12.0||3253||82||Nikon D3S|
|Pentax 645Z||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101||Pentax 645Z|
|Sony RX1R II||Full Frame||42.2||7952||5304||1080/60p||25.8||13.9||3204||97||Sony RX1R II|
|Sony A7R||Full Frame||36.2||7360||4912||1080/60p||25.6||14.1||2746||95||Sony A7R|
|Sony A3000||APS-C||19.8||5456||3632||1080/60i||23.7||12.8||1068||78||Sony A3000|
|Sony RX1R||Full Frame||24.0||6000||4000||1080/60p||25.0||13.6||2537||91||Sony RX1R|
|Sony NEX-7||APS-C||24.0||6000||4000||1080/60i||24.1||13.4||1016||81||Sony NEX-7|
Many modern cameras cannot only take still pictures, but also record videos. The RX1 indeed provides for movie recording, while the 645D does not. The highest resolution format that the RX1 can use is 1080/60p.
Apart from body and sensor, cameras can and do differ across a variety of features. For example, the 645D has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the RX1 relies on live view and the rear LCD for framing. That said, the RX1 can be equipped with an optional viewfinder – the FDA-EV1MK. The adjacent table lists some of the other core features of the Pentax 645D and Sony RX1 along with similar information for a selection of comparators.
|Pentax 645D||optical||Y||3.0||921||fixed||n||1/4000s||1.1||n||n||Pentax 645D|
|Sony RX1||optional||n||3.0||1229||fixed||n||1/4000s||5.0||Y||n||Sony RX1|
|Canon 1D X Mark II||optical||Y||3.2||1620||fixed||Y||1/8000s||16.0||n||n||Canon 1D X Mark II|
|Canon 1D X||optical||Y||3.2||1040||fixed||n||1/8000s||14.0||n||n||Canon 1D X|
|Canon 1D Mark IV||optical||Y||3.0||920||fixed||n||1/8000s||10.0||n||n||Canon 1D Mark IV|
|Leica S Typ 006||optical||Y||3.0||922||fixed||n||1/4000s||1.5||n||n||Leica S Typ 006|
|Nikon D850||optical||Y||3.2||2359||tilting||Y||1/8000s||9.0||n||n||Nikon D850|
|Nikon D5||optical||Y||3.2||2359||fixed||Y||1/8000s||14.0||n||n||Nikon D5|
|Nikon D810||optical||Y||3.2||1229||fixed||n||1/8000s||5.0||Y||n||Nikon D810|
|Nikon D5300||optical||n||3.2||1037||swivel||n||1/4000s||5.0||Y||n||Nikon D5300|
|Nikon D3S||optical||Y||3.0||921||fixed||n||1/8000s||11.0||n||n||Nikon D3S|
|Pentax 645Z||optical||Y||3.2||1037||tilting||n||1/4000s||3.0||n||n||Pentax 645Z|
|Sony RX1R II||2360||n||3.0||1229||tilting||n||1/4000s||5.0||n||n||Sony RX1R II|
|Sony A7R||2400||n||3.0||1230||tilting||n||1/8000s||4.0||n||n||Sony A7R|
|Sony A3000||202||n||3.0||230||fixed||n||1/4000s||2.5||Y||n||Sony A3000|
|Sony RX1R||optional||n||3.0||1229||fixed||n||1/4000s||5.0||Y||n||Sony RX1R|
|Sony NEX-7||2359||n||3.0||921||tilting||n||1/4000s||10.0||Y||n||Sony NEX-7|
One feature that is present on the 645D, but is missing on the RX1 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.
The Pentax 645D 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 645D writes its imaging data to SDXC cards, while the RX1 uses SDXC or Memory Stick PRO Duo cards. The 645D features dual card slots, which can be very useful in case a memory card fails. In contrast, the RX1 only has one slot.
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 645D and Sony Cyber-shot DSC-RX1 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
|Pentax 645D||Y||stereo||none||-||-||none||2.0||-||-||-||Pentax 645D|
|Sony RX1||Y||stereo||mono||Y||-||mini||2.0||-||-||-||Sony RX1|
|Canon 1D X Mark II||Y||mono||mono||Y||Y||mini||3.0||-||-||-||Canon 1D X Mark II|
|Canon 1D X||Y||mono||none||Y||-||mini||2.0||-||-||-||Canon 1D X|
|Canon 1D Mark IV||Y||stereo||none||Y||-||mini||2.0||-||-||-||Canon 1D Mark IV|
|Leica S Typ 006||Y||none||none||-||-||mini||2.0||-||-||-||Leica S Typ 006|
|Nikon D850||Y||stereo||mono||Y||Y||mini||3.0||Y||Y||Y||Nikon D850|
|Nikon D5||Y||stereo||mono||Y||Y||mini||3.0||-||-||-||Nikon D5|
|Nikon D810||Y||stereo||mono||Y||Y||mini||3.0||Y||-||-||Nikon D810|
|Nikon D5300||Y||stereo||mono||Y||-||mini||2.0||Y||-||-||Nikon D5300|
|Nikon D3S||Y||stereo||none||-||-||mini||2.0||-||-||-||Nikon D3S|
|Pentax 645Z||Y||stereo||mono||Y||-||mini||3.0||-||-||-||Pentax 645Z|
|Sony RX1R II||Y||stereo||mono||Y||-||micro||2.0||Y||Y||-||Sony RX1R II|
|Sony A7R||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-||Sony A7R|
|Sony A3000||Y||stereo||mono||-||-||mini||2.0||-||-||-||Sony A3000|
|Sony RX1R||Y||stereo||mono||Y||-||mini||2.0||-||-||-||Sony RX1R|
|Sony NEX-7||Y||stereo||mono||Y||-||mini||2.0||-||-||-||Sony NEX-7|
Studio photographers will appreciate that the Pentax 645D (unlike the RX1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the 645D and the RX1 have been discontinued, but can regularly be found used on eBay. The 645D was replaced by the Pentax 645Z, while the RX1 was followed by the Sony RX1R. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Pentax and Sony websites.
So what conclusions can be drawn? Is there a clear favorite between the Pentax 645D and the Sony RX1? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.
Arguments in favor of the Pentax 645D:
- More detail: Offers more megapixels (39.5 vs 24MP) with a 26% higher linear resolution.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- 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.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More flexible: Can take a variety of interchangeable lenses, including specialty optics.
- Longer lasting: Can take more shots (800 versus 270) on a single battery charge.
- Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
- 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 March 2010).
Advantages of the Sony Cyber-shot DSC-RX1:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better image quality: Scores substantially higher (11 points) in the DXO overall evaluation.
- More dynamic range: Captures a broader range of light and dark details (1.7 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (1 stops ISO advantage).
- Broader imaging potential: Can capture not only stills but also 1080/60p video.
- More detailed LCD: Has a higher resolution rear screen (1229k vs 921k dots).
- Faster burst: Shoots at higher frequency (5 vs 1.1 flaps/sec) to capture the decisive moment.
- Ready to shoot: Comes with an integrated lens, while the 645D requires a separate lens.
- More compact: Is smaller (113x65mm vs 156x117mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight even though it has a lens built in (unlike the 645D).
- Easier travel charging: Can be conveniently charged via its USB port.
- Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
- More affordable: Was introduced at a lower price, despite coming with a built-in lens.
- More modern: Reflects 2 years and 6 months of technical progress since the 645D launch.
If the count of individual advantages (bullet points above) is taken as a guide, the RX1 emerges as the winner of the match-up (13 : 11 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 645D and the Sony RX1 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 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 645D and the RX1 in practical situations. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable.
This is where reviews by experts come in. The adjacent summary-table relays the overall verdicts of several of the most popular 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 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. 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? If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes below. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.
Specifications: Pentax 645D vs Sony RX1
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 645D||Sony RX1|
|Camera Type||Digital single lens reflex||Fixed lens compact camera|
|Camera Lens||Pentax 645 mount lenses||35mm f/2.0|
|Launch Date||March 2010||September 2012|
|Launch Price||USD 9995||USD 2799|
|Sensor Specs||Pentax 645D||Sony RX1|
|Sensor Format||Medium Format Sensor||Full Frame Sensor|
|Sensor Size||44.0 x 33.0 mm||35.8 x 23.8 mm|
|Sensor Area||1452 mm2||852.04 mm2|
|Sensor Diagonal||55 mm||43 mm|
|Sensor Resolution||39.5 Megapixels||24 Megapixels|
|Image Resolution||7264 x 5440 pixels||6000 x 4000 pixels|
|Pixel Pitch||6.06 μm||5.96 μm|
|Pixel Density||2.72 MP/cm2||2.82 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||no Video||1080/60p Video|
|ISO Setting||100-1600 ISO||100-25600 ISO|
|ISO Boost||no Enhancement||50-102400 ISO|
|Image Processor||PRIME II||BIONZ X|
|DXO Sensor Quality (score)||82||93|
|DXO Color Depth (bits)||24.6||25.1|
|DXO Dynamic Range (EV)||12.6||14.3|
|DXO Low Light (ISO)||1262||2534|
|Screen Specs||Pentax 645D||Sony RX1|
|Viewfinder Type||Optical viewfinder||Viewfinder optional|
|Viewfinder Field of View||98%|
|Top-Level Screen||Control Panel||no Top Display|
|LCD Framing||Live View|
|Rear LCD Size||3.0 inch||3.0 inch|
|LCD Resolution||921k dots||1229k dots|
|LCD Attachment||Fixed screen||Fixed screen|
|Shooting Specs||Pentax 645D||Sony RX1|
|Focus System||Phase-detect AF||Contrast-detect AF|
|Manual Focusing Aid||No Peaking Feature||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000/s||1/4000/s|
|Continuous Shooting||1.1 shutter flaps/s||5 shutter flaps/s|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Fill Flash||no On-Board Flash||Build-in Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Dual card slots||Single card slot|
|UHS card support||no||no|
|Connectivity Specs||Pentax 645D||Sony RX1|
|Studio Flash||PC Sync socket||no PC Sync|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||no HDMI||mini HDMI|
|Microphone Port||no MIC socket||External MIC port|
|Wifi Support||no Wifi||no Wifi|
|Body Specs||Pentax 645D||Sony RX1|
|Environmental Sealing||Weathersealed body||Not weather sealed|
|Battery Life (CIPA)||800 shots per charge||270 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
156 x 117 x 119 mm
(6.1 x 4.6 x 4.7 in)
113 x 65 x 70 mm
(4.4 x 2.6 x 2.8 in)
|Camera Weight||1480 g (52.2 oz)||482 g (17.0 oz)|
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