Pentax 645D vs Sony A99 II
The Pentax 645D and the Sony Alpha ALT-A99 II are two professional cameras that were announced, respectively, in March 2010 and September 2016. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a medium format (645D) and a full frame (A99 II) sensor. The Pentax has a resolution of 39.5 megapixels, whereas the Sony provides 42.2 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 Alpha ALT-A99 II? 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 645D and the Sony A99 II 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 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 A99 II is notably smaller (19 percent) than the Pentax 645D. Moreover, the A99 II is substantially lighter (43 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.
The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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.
|Pentax 645D||6.1 in||4.6 in||4.7 in||52.2 oz||800||Y||Mar 2010||9,995|
|Sony A99 II||5.6 in||4.1 in||3.0 in||29.9 oz||490||Y||Sep 2016||3,199|
|Canon 1D X Mark II||6.2 in||6.6 in||3.3 in||54.0 oz||1210||Y||Feb 2016||5,999|
|Canon 5DS R||6.0 in||4.6 in||3.0 in||32.8 oz||700||Y||Feb 2015||3,699|
|Canon 1D X||6.2 in||6.6 in||3.3 in||54.7 oz||1120||Y||Oct 2011||6,799|
|Canon 1D Mark IV||6.1 in||6.2 in||3.1 in||43.4 oz||1500||Y||Oct 2009||4,999|
|Leica S Typ 006||6.3 in||4.7 in||3.1 in||44.4 oz||..||Y||Sep 2012||21,950|
|Nikon D850||5.7 in||4.9 in||3.1 in||35.5 oz||1840||Y||Jul 2017||3,299|
|Nikon D5||6.3 in||6.3 in||3.6 in||49.9 oz||3780||Y||Jan 2016||6,499|
|Nikon D810||5.7 in||4.8 in||3.2 in||34.6 oz||1200||Y||Jun 2014||3,299|
|Nikon D3S||6.3 in||6.2 in||3.5 in||43.7 oz||4200||Y||Oct 2009||5,199|
|Pentax 645Z||6.1 in||4.6 in||4.8 in||54.7 oz||650||Y||Apr 2014||8,499|
|Sony A7R II||5.0 in||3.8 in||2.4 in||22.0 oz||290||Y||Jun 2015||3,199|
|Sony A7S II||5.0 in||3.8 in||2.4 in||22.1 oz||370||Y||Sep 2015||2,999|
|Sony A7R||5.0 in||3.7 in||1.9 in||16.4 oz||340||Y||Oct 2013||2,299|
|Sony A99||5.8 in||4.4 in||3.1 in||28.6 oz||500||Y||Sep 2012||2,799|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
The price is, of course, an important factor in any camera decision. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The A99 II was launched at a markedly lower price (by 68 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 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. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its background. On the downside, larger sensors are more costly to manufacture and tend to 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 A99 II a full frame sensor. The sensor area in the A99 II 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 A99 II offers a 3:2 aspect.
Despite having a smaller sensor, the A99 II offers a slightly higher resolution of 42.2 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 4.52μm versus 6.06μm for the 645D). However, it should be noted that the A99 II is much more recent (by 6 years and 6 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 A99 II implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A99 II for good quality output (200 dots per inch) amounts to 39.8 x 26.5 inches or 101 x 67.4 cm, for very good quality (250 dpi) 31.8 x 21.2 inches or 80.8 x 53.9 cm, and for excellent quality (300 dpi) 26.5 x 17.7 inches or 67.3 x 44.9 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 A99 II has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
The Pentax 645D has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Sony Alpha ALT-A99 II are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-25600.
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"). Of the two cameras under consideration, the A99 II has a markedly higher DXO score than the 645D (overall score 10 points higher), which will translate into better image quality. The advantage is based on 0.8 bits higher color depth, 0.8 EV in additional dynamic range, and 0.9 stops in additional low light sensitivity. The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.
| DXO |
|Pentax 645D||Medium Format||39.5||7264||5440||none||24.6||12.6||1262||82|
|Sony A99 II||Full Frame||42.2||7952||5304||4K/30p||25.4||13.4||2317||92|
|Canon 1D X Mark II||Full Frame||20.0||5472||3648||4K/60p||24.1||13.5||3207||88|
|Canon 5DS R||Full Frame||50.3||8688||5792||1080/30p||24.6||12.4||2308||86|
|Canon 1D X||Full Frame||17.9||5184||3456||1080/30p||23.8||11.8||2786||82|
|Canon 1D Mark IV||APS-H||16.0||4896||3264||1080/30p||22.8||12.0||1320||74|
|Leica S Typ 006||Medium Format||37.5||7500||5000||none||23.9||12.2||824||76|
|Nikon D850||Full Frame||45.4||8256||5504||4K/30p||26.4||14.8||2660||100|
|Nikon D5||Full Frame||20.7||5588||3712||4K/30p||25.1||12.3||2343||88|
|Nikon D810||Full Frame||36.2||7360||4912||1080/60p||25.7||14.8||2853||97|
|Nikon D3S||Full Frame||12.1||4256||2832||720/24p||23.5||12.0||3253||82|
|Pentax 645Z||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101|
|Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
|Sony A7R||Full Frame||36.2||7360||4912||1080/60p||25.6||14.1||2746||95|
|Sony A99||Full Frame||24.0||6000||4000||1080/60p||25.0||14.0||1555||89|
Many modern cameras cannot only take still pictures, but also record videos. The A99 II indeed provides for movie recording, while the 645D does not. The highest resolution format that the A99 II can use is 4K/30p.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the A99 II has an electronic viewfinder (2400k 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 viewfinders of both cameras offer the same magnification (0.78x), but the one in the A99 II has a wider field of view (100%) than the finder in the 645D (98%), so that a larger proportion of the captured image is visible. The table below summarizes some of the other core capabilities of the Pentax 645D and Sony A99 II in connection with corresponding information for a sample of similar cameras.
|Sony A99 II||2400||Y||3.0||1229||full-flex||n||1/8000s||12.0||n||Y|
|Canon 1D X Mark II||optical||Y||3.2||1620||fixed||Y||1/8000s||16.0||n||n|
|Canon 5DS R||optical||Y||3.2||1040||fixed||n||1/8000s||5.0||n||n|
|Canon 1D X||optical||Y||3.2||1040||fixed||n||1/8000s||14.0||n||n|
|Canon 1D Mark IV||optical||Y||3.0||920||fixed||n||1/8000s||10.0||n||n|
|Leica S Typ 006||optical||Y||3.0||922||fixed||n||1/4000s||1.5||n||n|
|Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|Sony A7S II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
One feature that differentiates the A99 II and the 645D is in-body image stabilization (IBIS). The A99 II reduces the risk of handshake-induced blur with all attached lenses, while the 645D offers no blur reduction with lenses that themselves do not provide optical image stabilization.The A99 II 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 645D does not have a selfie-screen.
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 A99 II uses SDXC or Memory Stick PRO Duo cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. The A99 II 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 Pentax 645D and Sony Alpha ALT-A99 II and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|Sony A99 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||Y|
|Canon 1D X Mark II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
|Canon 5DS R||Y||mono||mono||Y||-||mini||3.0||-||-||-|
|Canon 1D X||Y||mono||-||Y||-||mini||2.0||-||-||-|
|Canon 1D Mark IV||Y||stereo||-||Y||-||mini||2.0||-||-||-|
|Leica S Typ 006||Y||-||-||-||-||mini||2.0||-||-||-|
|Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|Sony A7S II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A99 II 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 A99 II 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 conclusions can be drawn? Is the Pentax 645D better than the Sony A99 II or vice versa? Below is a summary of the relative strengths of each of the two contestants.
Advantages of the Pentax 645D:
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- Longer lasting: Can take more shots (800 versus 490) on a single battery charge.
- More heavily discounted: Has been available for much longer (launched in March 2010).
Reasons to prefer the Sony Alpha ALT-A99 II:
- More detail: Has more megapixels (42.2 vs 39.5MP), which boosts linear resolution by 5%.
- Better image quality: Scores markedly higher (10 points) in the DXO overall evaluation.
- More dynamic range: Captures a broader range of light and dark details (0.8 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (0.9 stops ISO advantage).
- Broader imaging potential: Can capture not only stills but also 4K/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%).
- More detailed LCD: Has a higher resolution rear screen (1229k vs 921k dots).
- More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (12 vs 1.1 flaps/sec) to capture the decisive moment.
- More compact: Is smaller (143x104mm vs 156x117mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight (by 631g or 43 percent) and is thus easier to take along.
- Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
- 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 into a lower priced category (68 percent cheaper at launch).
- More modern: Reflects 6 years and 6 months of technical progress since the 645D launch.
If the count of relative strengths (bullet points above) is taken as a measure, the A99 II is the clear winner of the contest (23 : 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 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 645D and the Sony A99 II place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing 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 remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the 645D or the A99 II. 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 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.
|Pentax 645D||..||..||..||4.5/5||..||Mar 2010||9,995|
|Sony A99 II||..||85/100||4.5/5||4.5/5||4.5/5||Sep 2016||3,199|
|Canon 1D X Mark II||..||89/100||4.5/5||5/5||4.5/5||Feb 2016||5,999|
|Canon 5DS R||+||83/100||5/5||5/5||4.5/5||Feb 2015||3,699|
|Canon 1D X||..||..||4.5/5||4.5/5||4.5/5||Oct 2011||6,799|
|Canon 1D Mark IV||..||89/100||..||5/5||..||Oct 2009||4,999|
|Leica S Typ 006||..||..||..||..||..||Sep 2012||21,950|
|Nikon D850||+ +||89/100||4.5/5||5/5||5/5||Jul 2017||3,299|
|Nikon D5||..||89/100||4.5/5||5/5||5/5||Jan 2016||6,499|
|Nikon D810||..||86/100||5/5||4.5/5||4.5/5||Jun 2014||3,299|
|Nikon D3S||..||89/100||4.5/5||5/5||5/5||Oct 2009||5,199|
|Pentax 645Z||..||..||4.5/5||5/5||5/5||Apr 2014||8,499|
|Sony A7R II||+ +||90/100||5/5||4.5/5||5/5||Jun 2015||3,199|
|Sony A7S II||+||..||4.5/5||5/5||5/5||Sep 2015||2,999|
|Sony A7R||+ +||82/100||4.5/5||5/5||5/5||Oct 2013||2,299|
|Sony A99||..||84/100||4.5/5||o||4.5/5||Sep 2012||2,799|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
Care should be taken when interpreting the review scores above, 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, 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? 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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.
Specifications: Pentax 645D vs Sony A99 II
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 A99 II|
|Camera Type||Digital single lens reflex||Digital single lens reflex|
|Camera Lens||Pentax 645 mount lenses||Sony A mount lenses|
|Launch Date||March 2010||September 2016|
|Launch Price||USD 9,995||USD 3,199|
|Sensor Specs||Pentax 645D||Sony A99 II|
|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||42.2 Megapixels|
|Image Resolution||7264 x 5440 pixels||7952 x 5304 pixels|
|Pixel Pitch||6.06 μm||4.52 μm|
|Pixel Density||2.72 MP/cm2||4.90 MP/cm2|
|Moiré control||no AA filter||no AA filter|
|Movie Capability||no Video||4K/30p Video|
|ISO Setting||100 - 1,600 ISO||100 - 25,600 ISO|
|ISO Boost||no Enhancement||50 - 25,600 ISO|
|Image Processor||PRIME II||BIONZ X|
|DXO Sensor Quality (score)||82||92|
|DXO Color Depth (bits)||24.6||25.4|
|DXO Dynamic Range (EV)||12.6||13.4|
|DXO Low Light (ISO)||1262||2317|
|Screen Specs||Pentax 645D||Sony A99 II|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||98%||100%|
|Viewfinder Resolution||2400k dots|
|Top-Level Screen||Control Panel||Control Panel|
|LCD Framing||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||921k dots||1229k dots|
|LCD Attachment||Fixed screen||Fully flexible screen|
|Shooting Specs||Pentax 645D||Sony A99 II|
|Focus System||Phase-detect AF||Phase-detect AF|
|Manual Focusing Aid||no Peaking Feature||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/8000s|
|Continuous Shooting||1.1 shutter flaps/s||12 shutter flaps/s|
|Shutter Life Expectancy||50 000 actuations||300 000 actuations|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||Lens stabilization only||In-body stabilization|
|Fill Flash||no On-Board Flash||no On-Board Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Dual card slots||Dual card slots|
|UHS card support||no||UHS-I|
|Connectivity Specs||Pentax 645D||Sony A99 II|
|Studio Flash||PC Sync socket||PC Sync socket|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||no HDMI||micro HDMI|
|Microphone Port||no MIC socket||External MIC port|
|Headphone Socket||no Headphone port||Headphone 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 645D||Sony A99 II|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||800 shots per charge||490 shots per charge|
156 x 117 x 119 mm
(6.1 x 4.6 x 4.7 in)
143 x 104 x 76 mm
(5.6 x 4.1 x 3.0 in)
|Camera Weight||1480 g (52.2 oz)||849 g (29.9 oz)|
Did you notice an error on this page? If so, please get in touch, so that we can correct the information.