Pentax 645Z vs Sony A6100
The Pentax 645Z and the Sony Alpha A6100 are two digital cameras that were announced, respectively, in April 2014 and August 2019. The 645Z is a DSLR, while the A6100 is a mirrorless interchangeable lens camera. The cameras are based on a medium format (645Z) and an APS-C (A6100) sensor. The Pentax has a resolution of 51.1 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.
Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax 645Z and the Sony Alpha A6100? 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 Pentax 645Z and the Sony A6100 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 width, height and depth dimensions are rounded to the nearest millimeter.
The A6100 can be obtained in three different colors (black, silver, white), while the 645Z 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 Sony A6100 is considerably smaller (56 percent) than the Pentax 645Z. Moreover, the A6100 is substantially lighter (74 percent) than the 645Z. It is worth mentioning in this context that the 645Z is splash and dust resistant, while the A6100 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 645Z gets 650 shots out of its D-LI90 battery, while the A6100 can take 420 images on a single charge of its NP-FW50 power pack. The power pack in the A6100 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. 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.||Pentax 645Z||156 mm||117 mm||123 mm||1550 g||650||Y||Apr 2014||8,499|
|2.||Sony A6100||120 mm||67 mm||59 mm||396 g||420||n||Aug 2019||749|
|3.||Canon 1D X Mark II||158 mm||168 mm||83 mm||1530 g||1210||Y||Feb 2016||5,999|
|4.||Canon 5DS||152 mm||116 mm||76 mm||930 g||700||Y||Feb 2015||3,699|
|5.||Canon 5DS R||152 mm||116 mm||76 mm||930 g||700||Y||Feb 2015||3,699|
|6.||Fujifilm X-T30||118 mm||83 mm||47 mm||383 g||380||n||Feb 2019||899|
|7.||Hasselblad X1D||150 mm||98 mm||71 mm||725 g||..||Y||Jun 2016||8,995|
|8.||Leica SL||147 mm||104 mm||39 mm||847 g||400||Y||Oct 2015||7,450|
|9.||Nikon D850||146 mm||124 mm||79 mm||1005 g||1840||Y||Jul 2017||3,299|
|10.||Nikon D5||160 mm||159 mm||92 mm||1415 g||3780||Y||Jan 2016||6,499|
|11.||Nikon D7200||136 mm||107 mm||76 mm||765 g||1110||Y||Mar 2015||1,199|
|12.||Nikon D4S||160 mm||157 mm||91 mm||1350 g||3020||Y||Feb 2014||6,499|
|13.||Pentax 645D||156 mm||117 mm||119 mm||1480 g||800||Y||Mar 2010||9,995|
|14.||Sony A6400||120 mm||67 mm||50 mm||403 g||410||Y||Jan 2019||899|
|15.||Sony A6000||120 mm||67 mm||45 mm||344 g||360||n||Feb 2014||599|
|16.||Sony A3000||128 mm||91 mm||85 mm||411 g||470||n||Aug 2013||329|
|17.||Sony NEX-7||120 mm||67 mm||43 mm||400 g||430||n||Aug 2011||1,349|
|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 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 A6100 was launched at a markedly lower price (by 91 percent) than the 645Z, 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 sensor inside a digital camera is one of the key determinants 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. 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 associated with larger, more expensive camera bodies and lenses.
Of the two cameras under consideration, the Pentax 645Z features a medium format sensor and the Sony A6100 an APS-C sensor. The sensor area in the A6100 is 74 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 0.79 and 1.5. The sensor in the 645Z has a native 4:3 aspect ratio, while the one in the A6100 offers a 3:2 aspect.
With 51.1MP, the 645Z offers a higher resolution than the A6100 (24MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 3.91μm for the A6100) due to its larger sensor. However, the A6100 is a much more recent model (by 5 years and 4 months) than the 645Z, 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 645Z has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the Pentax 645Z implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 645Z for good quality output (200 dots per inch) amounts to 41.3 x 31 inches or 104.9 x 78.6 cm, for very good quality (250 dpi) 33 x 24.8 inches or 83.9 x 62.9 cm, and for excellent quality (300 dpi) 27.5 x 20.6 inches or 69.9 x 52.4 cm. The corresponding values for the Sony A6100 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 A6100 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
The Pentax 645Z has a native sensitivity range from ISO 100 to ISO 204800. The corresponding ISO settings for the Sony Alpha A6100 are ISO 100 to ISO 32000, with the possibility to increase the ISO range to 100-51200.
For many cameras, data on sensor performance has been reported by DXO Mark. 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 following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.
| DXO |
|1.||Pentax 645Z||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101|
|3.||Canon 1D X Mark II||Full Frame||20.0||5472||3648||4K/60p||24.1||13.5||3207||88|
|4.||Canon 5DS||Full Frame||50.3||8688||5792||1080/30p||24.7||12.4||2381||87|
|5.||Canon 5DS R||Full Frame||50.3||8688||5792||1080/30p||24.6||12.4||2308||86|
|7.||Hasselblad X1D||Medium Format||51.3||8272||6200||1080/25p||26.2||14.8||4489||102|
|8.||Leica SL||Full Frame||24.0||6000||4000||4K/30p||25.0||13.4||1821||88|
|9.||Nikon D850||Full Frame||45.4||8256||5504||4K/30p||26.4||14.8||2660||100|
|10.||Nikon D5||Full Frame||20.7||5588||3712||4K/30p||25.1||12.3||2343||88|
|12.||Nikon D4S||Full Frame||16.2||4928||3280||1080/60p||24.4||13.3||3074||89|
|13.||Pentax 645D||Medium Format||39.5||7264||5440||none||24.6||12.6||1262||82|
Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A6100 provides a better video resolution than the 645Z. It can shoot movie footage at 4K/30p, 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 A6100 has an electronic viewfinder (1440k dots), while the 645Z 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 A6100 offers a wider field of view (100%) than the one in the 645Z (98%), so that a larger proportion of the captured image is visible in the finder. On the other hand, the viewfinder of the 645Z has a higher magnification (0.78x vs 0.70x), 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 645Z, the Sony A6100, and comparable cameras.
|3.||Canon 1D X Mark II||optical||Y||3.2||1620||fixed||Y||1/8000s||16.0||n||n|
|5.||Canon 5DS R||optical||Y||3.2||1040||fixed||n||1/8000s||5.0||n||n|
One feature that is present on the 645Z, but is missing on the A6100 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 A6100 has an articulated screen that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in taking selfies. In contrast, the 645Z does not have a selfie-screen.
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 A6100 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 645Z and the Sony A6100 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 645Z writes its imaging data to SDXC cards, while the A6100 uses SDXC or Memory Stick PRO Duo cards. The 645Z features dual card slots, which can be very useful in case a memory card fails. In contrast, the A6100 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 645Z and Sony Alpha A6100 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||-||-||-|
|5.||Canon 5DS R||Y||mono||mono||Y||-||mini||3.0||-||-||-|
It is notable that the A6100 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the 645Z does not provide wifi capability.
Studio photographers will appreciate that the Pentax 645Z (unlike the A6100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the 645Z and the A6100 are recent models that are part of the current product line-up. The 645Z replaced the earlier Pentax 645D, while the A6100 followed on from the Sony A6000. 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? Which of the two cameras – the Pentax 645Z or the Sony A6100 – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.
Arguments in favor of the Pentax 645Z:
- More detail: Offers more megapixels (51.1 vs 24MP) with a 43% higher linear resolution.
- 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.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.70x).
- 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.
- More detailed LCD: Has a higher resolution rear screen (1037k vs 922k dots).
- Longer lasting: Can take more shots (650 versus 420) on a single battery charge.
- Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
- Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
- 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 April 2014).
Reasons to prefer the Sony Alpha A6100:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
- 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%).
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster burst: Shoots at higher frequency (11 vs 3 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- More compact: Is smaller (120x67mm vs 156x117mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight (by 1154g or 74 percent) and is thus easier to take along.
- Easier travel charging: Can be conveniently charged via its USB port.
- More legacy lens friendly: Can use many non-native lenses via adapters.
- Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
- 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.
- More affordable: Was introduced into a lower priced category (91 percent cheaper at launch).
- More modern: Reflects 5 years and 4 months of technical progress since the 645Z launch.
If the number of relative strengths (bullet points above) is taken as a guide, the A6100 is the clear winner of the contest (19 : 13 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 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 Pentax 645Z and the Sony A6100 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 says little about, for example, the shooting experience and imaging performance of the 645Z and the A6100 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 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 645Z||5/5||..||..||4.5/5||5/5||Apr 2014||8,499|
|2.||Sony A6100||..||..||82/100||4/5||5/5||Aug 2019||749|
|3.||Canon 1D X Mark II||..||..||89/100||4.5/5||4.5/5||Feb 2016||5,999|
|4.||Canon 5DS||..||+||83/100||4.5/5||4.5/5||Feb 2015||3,699|
|5.||Canon 5DS R||5/5||+||83/100||5/5||4.5/5||Feb 2015||3,699|
|6.||Fujifilm X-T30||5/5||+ +||84/100||4.5/5||4.5/5||Feb 2019||899|
|7.||Hasselblad X1D||..||o||81/100||..||4/5||Jun 2016||8,995|
|8.||Leica SL||4/5||..||84/100||4.5/5||4/5||Oct 2015||7,450|
|9.||Nikon D850||4.5/5||+ +||89/100||4.5/5||5/5||Jul 2017||3,299|
|10.||Nikon D5||..||..||89/100||4.5/5||5/5||Jan 2016||6,499|
|11.||Nikon D7200||4/5||+ +||84/100||4.5/5||4.5/5||Mar 2015||1,199|
|12.||Nikon D4S||5/5||..||..||4.5/5||4.5/5||Feb 2014||6,499|
|13.||Pentax 645D||5/5||..||..||..||..||Mar 2010||9,995|
|14.||Sony A6400||4/5||+||85/100||4.5/5||4/5||Jan 2019||899|
|15.||Sony A6000||5/5||+||80/100||4.5/5||5/5||Feb 2014||599|
|16.||Sony A3000||3/5||+||..||4/5||4/5||Aug 2013||329|
|17.||Sony NEX-7||5/5||+ +||81/100||4.5/5||5/5||Aug 2011||1,349|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The review scores listed above should be treated 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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. Also, please note that some of the review sites have changed their methodology and reporting over time.
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.
Specifications: Pentax 645Z vs Sony A6100
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 645Z||Sony A6100|
|Camera Type||Digital single lens reflex||Mirrorless system camera|
|Camera Lens||Pentax 645 mount lenses||Sony E mount lenses|
|Launch Date||April 2014||August 2019|
|Launch Price||USD 8,499||USD 749|
|Sensor Specs||Pentax 645Z||Sony A6100|
|Sensor Format||Medium Format Sensor||APS-C Sensor|
|Sensor Size||43.8 x 32.8 mm||23.5 x 15.6 mm|
|Sensor Area||1436.64 mm2||366.6 mm2|
|Sensor Diagonal||54.7 mm||28.2 mm|
|Sensor Resolution||51.1 Megapixels||24 Megapixels|
|Image Resolution||8256 x 6192 pixels||6000 x 4000 pixels|
|Pixel Pitch||5.30 μm||3.91 μm|
|Pixel Density||3.56 MP/cm2||6.55 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||1080/60i Video||4K/30p Video|
|ISO Setting||100 - 204,800 ISO||100 - 32,000 ISO|
|ISO Boost||no Enhancement||100 - 51,200 ISO|
|Image Processor||PRIME III||BIONZ X|
|DXO Sensor Quality (score)||101||..|
|DXO Color Depth (bits)||26.0||..|
|DXO Dynamic Range (EV)||14.7||..|
|DXO Low Light (ISO)||4505||..|
|Screen Specs||Pentax 645Z||Sony A6100|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||98%||100%|
|Viewfinder Resolution||1440k dots|
|Top-Level Screen||Control Panel||no Top Display|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.2inch||3.0inch|
|LCD Resolution||1037k dots||922k dots|
|LCD Attachment||Tilting screen||Tilting screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Pentax 645Z||Sony A6100|
|Focus System||Phase-detect AF||On-Sensor Phase-detect|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/4000s|
|Continuous Shooting||3 shutter flaps/s||11 shutter flaps/s|
|Shutter Life Expectancy||100 000 actuations||100 000 actuations|
|Electronic Shutter||no E-Shutter||YES|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|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||UHS-I||UHS-I|
|Connectivity Specs||Pentax 645Z||Sony A6100|
|Studio Flash||PC Sync socket||no PC Sync|
|USB Connector||USB 3.0||USB 2.0|
|HDMI Port||mini HDMI||micro HDMI|
|Microphone Port||External MIC port||External MIC port|
|Wifi Support||no Wifi||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Bluetooth Support||no Bluetooth||Bluetooth built-in|
|Body Specs||Pentax 645Z||Sony A6100|
|Environmental Sealing||Weathersealed body||not weather sealed|
|Battery Life (CIPA)||650 shots per charge||420 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
156 x 117 x 123 mm
(6.1 x 4.6 x 4.8 in)
120 x 67 x 59 mm
(4.7 x 2.6 x 2.3 in)
|Camera Weight||1550 g (54.7 oz)||396 g (14.0 oz)|
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