Pentax 645D vs Sony A1
The Pentax 645D and the Sony A1 are two professional cameras that were announced, respectively, in March 2010 and January 2021. The 645D is a DSLR, while the A1 is a mirrorless interchangeable lens camera. The cameras are based on a medium format (645D) and a full frame (A1) sensor. The Pentax has a resolution of 39.5 megapixels, whereas the Sony provides 49.8 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 Pentax 645D and the Sony A1? 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 A1 are illustrated in the side-by-side display below. 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.
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A1 is considerably smaller (31 percent) than the Pentax 645D. Moreover, the A1 is substantially lighter (50 percent) than the 645D. 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 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 645D gets 800 shots out of its D-LI90 battery, while the A1 can take 530 images on a single charge of its NP-FZ100 power pack. The power pack in the A1 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 would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.
|1.||Pentax 645D||156 mm||117 mm||119 mm||1480 g||800||Y||Mar 2010||9,995|
|2.||Sony A1||129 mm||97 mm||81 mm||737 g||530||Y||Jan 2021||6,499|
|3.||Canon 1D X Mark II||158 mm||168 mm||83 mm||1530 g||1210||Y||Feb 2016||5,999|
|4.||Canon 1D X||158 mm||168 mm||83 mm||1551 g||1120||Y||Oct 2011||6,799|
|5.||Canon 1D Mark IV||156 mm||157 mm||80 mm||1230 g||1500||Y||Oct 2009||4,999|
|6.||Leica S Typ 006||160 mm||120 mm||80 mm||1260 g||..||Y||Sep 2012||21,950|
|7.||Nikon D850||146 mm||124 mm||79 mm||1005 g||1840||Y||Jul 2017||3,299|
|8.||Nikon D5||160 mm||159 mm||92 mm||1415 g||3780||Y||Jan 2016||6,499|
|9.||Nikon D810||146 mm||123 mm||82 mm||980 g||1200||Y||Jun 2014||3,299|
|10.||Nikon D3S||160 mm||157 mm||88 mm||1240 g||4200||Y||Oct 2009||5,199|
|11.||Pentax 645Z||156 mm||117 mm||123 mm||1550 g||650||Y||Apr 2014||8,499|
|12.||Sony A7S III||127 mm||97 mm||81 mm||699 g||600||Y||Jul 2020||3,499|
|13.||Sony A7R IV||129 mm||96 mm||78 mm||665 g||670||Y||Jul 2019||3,499|
|14.||Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199|
|15.||Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|16.||Sony A7R II||127 mm||96 mm||60 mm||625 g||290||Y||Jun 2015||3,199|
|17.||Sony A7R||127 mm||94 mm||48 mm||465 g||340||Y||Oct 2013||2,299|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will naturally be influenced heavily by the price. 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 A1 was launched at a markedly lower price (by 35 percent) than the 645D, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.
The size of the imaging sensor is a crucial determinant of image quality. A large sensor will generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have richer color-depth than smaller pixels in a sensor of the same technological generation. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better 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 Pentax 645D features a medium format sensor and the Sony A1 a full frame sensor. The sensor area in the A1 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 A1 offers a 3:2 aspect.
Despite having a smaller sensor, the A1 offers a higher resolution of 49.8 megapixels, compared with 39.5 MP of the 645D. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 4.16μm versus 6.06μm for the 645D). However, it should be noted that the A1 is much more recent (by 10 years and 10 months) than the 645D, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. 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 resolution advantage of the Sony A1 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A1 for good quality output (200 dots per inch) amounts to 43.2 x 28.8 inches or 109.7 x 73.2 cm, for very good quality (250 dpi) 34.6 x 23 inches or 87.8 x 58.5 cm, and for excellent quality (300 dpi) 28.8 x 19.2 inches or 73.2 x 48.8 cm. The corresponding values for the Pentax 645D are 36.3 x 27.2 inches or 92.3 x 69.1 cm for good quality, 29.1 x 21.8 inches or 73.8 x 55.3 cm for very good quality, and 24.2 x 18.1 inches or 61.5 x 46.1 cm for excellent quality prints.
The A1 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
Unlike the 645D, the A1 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 Pentax 645D has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Sony A1 are ISO 100 to ISO 32000, with the possibility to increase the ISO range to 500-102400.
For many cameras, data on sensor performance has been reported by DXO Mark. 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.
| DXO |
|1.||Pentax 645D||Medium Format||39.5||7264||5440||none||24.6||12.6||1262||82|
|2.||Sony A1||Full Frame||49.8||8640||5760||8k/30p||..||..||..||..|
|3.||Canon 1D X Mark II||Full Frame||20.0||5472||3648||4K/60p||24.1||13.5||3207||88|
|4.||Canon 1D X||Full Frame||17.9||5184||3456||1080/30p||23.8||11.8||2786||82|
|5.||Canon 1D Mark IV||APS-H||16.0||4896||3264||1080/30p||22.8||12.0||1320||74|
|6.||Leica S Typ 006||Medium Format||37.5||7500||5000||none||23.9||12.2||824||76|
|7.||Nikon D850||Full Frame||45.4||8256||5504||4K/30p||26.4||14.8||2660||100|
|8.||Nikon D5||Full Frame||20.7||5588||3712||4K/30p||25.1||12.3||2343||88|
|9.||Nikon D810||Full Frame||36.2||7360||4912||1080/60p||25.7||14.8||2853||97|
|10.||Nikon D3S||Full Frame||12.1||4256||2832||720/24p||23.5||12.0||3253||82|
|11.||Pentax 645Z||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101|
|12.||Sony A7S III||Full Frame||12.0||4240||2832||4K/120p||23.7||13.9||2520||86|
|13.||Sony A7R IV||Full Frame||60.2||9504||6336||4K/30p||26.0||14.8||3344||99|
|14.||Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|15.||Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|16.||Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|17.||Sony A7R||Full Frame||36.2||7360||4912||1080/60p||25.6||14.1||2746||95|
Many modern cameras are not only capable of taking still images, but can also record movies. The A1 indeed provides for movie recording, while the 645D does not. The highest resolution format that the A1 can use is 8k/30p.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the A1 has an electronic viewfinder (9437k 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 viewfinder in the A1 offers a wider field of view (100%) than the one in the 645D (98%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A1 has a higher magnification (0.9x vs 0.78x), 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 Pentax 645D, the Sony A1, and comparable cameras.
|3.||Canon 1D X Mark II||optical||Y||3.2||1620||fixed||Y||1/8000s||16.0||n||n|
|4.||Canon 1D X||optical||Y||3.2||1040||fixed||n||1/8000s||14.0||n||n|
|5.||Canon 1D Mark IV||optical||Y||3.0||920||fixed||n||1/8000s||10.0||n||n|
|6.||Leica S Typ 006||optical||Y||3.0||922||fixed||n||1/4000s||1.5||n||n|
|12.||Sony A7S III||9440||n||3.0||1440||swivel||Y||1/8000s||10.0||n||Y|
|13.||Sony A7R IV||5760||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|14.||Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|16.||Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
One feature that is present on the 645D, but is missing on the A1 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 reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the A1 is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).
The Pentax 645D and the Sony A1 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.
The 645D writes its imaging data to SDXC cards, while the A1 uses CFexpress or SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. The A1 supports UHS-II cards (Ultra High Speed data transfer of up to 312 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 Pentax 645D and Sony A1 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|3.||Canon 1D X Mark II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
|4.||Canon 1D X||Y||mono||-||Y||-||mini||2.0||-||-||-|
|5.||Canon 1D Mark IV||Y||stereo||-||Y||-||mini||2.0||-||-||-|
|6.||Leica S Typ 006||Y||-||-||-||-||mini||2.0||-||-||-|
|12.||Sony A7S III||Y||stereo||mono||Y||Y||full||3.2||Y||-||Y|
|13.||Sony A7R IV||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|14.||Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|16.||Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A1 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the 645D does not provide wifi capability.
Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.
The A1 is a recent model that features in the current product line-up of Sony. 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 Pentax and Sony websites.
So what is the bottom line? Is the Pentax 645D better than the Sony A1 or vice versa? The listing below highlights the relative strengths of the two models.
Arguments in favor of the Pentax 645D:
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Easier setting verification: Features an LCD display on top to control shooting parameters.
- Longer lasting: Can take more shots (800 versus 530) on a single battery charge.
- More heavily discounted: Has been available for much longer (launched in March 2010).
Reasons to prefer the Sony A1:
- More detail: Has more megapixels (49.8 vs 39.5MP), which boosts linear resolution by 14%.
- High quality composites: Can combine several shots after pixel-shifting its sensor.
- Broader imaging potential: Can capture not only stills but also 8k/30p video.
- 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 complete view: Has a viewfinder with a larger field of view (100% vs 98%).
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.9x vs 0.78x).
- More detailed LCD: Has a higher resolution rear screen (1440k vs 921k dots).
- More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
- 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 (10 vs 1.1 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- More compact: Is smaller (129x97mm vs 156x117mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight (by 743g or 50 percent) and is thus easier to take along.
- Easier travel charging: Can be conveniently charged via its USB port.
- Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
- More legacy lens friendly: Can use many non-native lenses via adapters.
- 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.
- Faster buffer clearing: Has an SD card interface that supports the UHS-II standard.
- More affordable: Was introduced into a lower priced category (35 percent cheaper at launch).
- More modern: Reflects 10 years and 10 months of technical progress since the 645D launch.
If the count of relative strengths (bullet points above) is taken as a measure, the A1 is the clear winner of the contest (24 : 4 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 Pentax 645D and the Sony A1 place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens 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 remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the 645D or the A1. 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 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], 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.||Pentax 645D||5/5||..||..||..||..||Mar 2010||9,995|
|2.||Sony A1||5/5||o||93/100||4.5/5||5/5||Jan 2021||6,499|
|3.||Canon 1D X Mark II||..||..||89/100||4.5/5||4.5/5||Feb 2016||5,999|
|4.||Canon 1D X||5/5||..||..||4.5/5||4.5/5||Oct 2011||6,799|
|5.||Canon 1D Mark IV||5/5||..||89/100||..||..||Oct 2009||4,999|
|6.||Leica S Typ 006||..||..||..||..||..||Sep 2012||21,950|
|7.||Nikon D850||4.5/5||+ +||89/100||4.5/5||5/5||Jul 2017||3,299|
|8.||Nikon D5||..||..||89/100||4.5/5||5/5||Jan 2016||6,499|
|9.||Nikon D810||5/5||..||86/100||5/5||4.5/5||Jun 2014||3,299|
|10.||Nikon D3S||5/5||..||89/100||4.5/5||5/5||Oct 2009||5,199|
|11.||Pentax 645Z||5/5||..||..||4.5/5||5/5||Apr 2014||8,499|
|12.||Sony A7S III||..||+ +||91/100||4.5/5||5/5||Jul 2020||3,499|
|13.||Sony A7R IV||5/5||+||91/100||4.5/5||5/5||Jul 2019||3,499|
|14.||Sony A7R III||..||+ +||90/100||4.5/5||5/5||Oct 2017||3,199|
|15.||Sony A9||5/5||+ +||89/100||5/5||5/5||Apr 2017||4,499|
|16.||Sony A7R II||5/5||+ +||90/100||5/5||5/5||Jun 2015||3,199|
|17.||Sony A7R||5/5||+ +||82/100||4.5/5||5/5||Oct 2013||2,299|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The above review scores should be interpreted with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. It should also be noted that some of the review sites have over time altered the way they render their verdicts.
Other camera comparisons
Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.
Specifications: Pentax 645D vs Sony A1
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 A1|
|Camera Type||Digital single lens reflex||Mirrorless system camera|
|Camera Lens||Pentax 645 mount lenses||Sony E mount lenses|
|Launch Date||March 2010||January 2021|
|Launch Price||USD 9,995||USD 6,499|
|Sensor Specs||Pentax 645D||Sony A1|
|Sensor Format||Medium Format Sensor||Full Frame Sensor|
|Sensor Size||44.0 x 33.0 mm||35.9 x 24.0 mm|
|Sensor Area||1452 mm2||861.6 mm2|
|Sensor Diagonal||55 mm||43.2 mm|
|Sensor Resolution||39.5 Megapixels||49.8 Megapixels|
|Image Resolution||7264 x 5440 pixels||8640 x 5760 pixels|
|Pixel Pitch||6.06 μm||4.16 μm|
|Pixel Density||2.72 MP/cm2||5.78 MP/cm2|
|Moiré control||no AA filter||no AA filter|
|Movie Capability||no Video||8k/30p Video|
|ISO Setting||100 - 1,600 ISO||100 - 32,000 ISO|
|ISO Boost||no Enhancement||500 - 102,400 ISO|
|Image Processor||PRIME II||Dual BIONZ XR|
|DXO Sensor Quality (score)||82||..|
|DXO Color Depth (bits)||24.6||..|
|DXO Dynamic Range (EV)||12.6||..|
|DXO Low Light (ISO)||1262||..|
|Screen Specs||Pentax 645D||Sony A1|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||98%||100%|
|Viewfinder Resolution||9437k dots|
|Top-Level Screen||Control Panel||no Top Display|
|LCD Framing||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||921k dots||1440k dots|
|LCD Attachment||Fixed screen||Tilting screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Pentax 645D||Sony A1|
|Focus System||Phase-detect AF||On-Sensor Phase-detect|
|Manual Focusing Aid||no Peaking Feature||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/8000s|
|Continuous Shooting||1.1 shutter flaps/s||10 shutter flaps/s|
|Shutter Life Expectancy||50 000 actuations||500 000 actuations|
|Electronic Shutter||no E-Shutter||up to 1/32000s|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|Image Stabilization||Lens stabilization only||In-body stabilization|
|Fill Flash||no On-Board Flash||no On-Board Flash|
|Storage Medium||SDXC cards||CFexpress or SDXC cards|
|Second Storage Option||Dual card slots||Dual card slots|
|UHS card support||no||UHS-II|
|Connectivity Specs||Pentax 645D||Sony A1|
|Studio Flash||PC Sync socket||PC Sync socket|
|USB Connector||USB 2.0||USB 3.2|
|HDMI Port||no HDMI||full 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|
|Body Specs||Pentax 645D||Sony A1|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||800 shots per charge||530 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)
129 x 97 x 81 mm
(5.1 x 3.8 x 3.2 in)
|Camera Weight||1480 g (52.2 oz)||737 g (26.0 oz)|
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