Canon XT vs Pentax 645D
The Canon EOS Rebel XT (called Canon 350D in some regions) and the Pentax 645D are two digital cameras that were announced, respectively, in February 2005 and March 2010. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (XT) and a medium format (645D) sensor. The Canon has a resolution of 8 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 EOS Rebel XT 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 XT 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.
The XT can be obtained in two different colors (black, silver), while the 645D 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 Pentax 645D is considerably larger (53 percent) than the Canon XT. Moreover, the 645D is substantially heavier (174 percent) than the XT. It is noteworthy in this context that the 645D is splash and dust-proof, while the XT 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.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.
|1.||Canon XT||127 mm||94 mm||64 mm||540 g||400||n||Feb 2005||899|
|2.||Pentax 645D||156 mm||117 mm||119 mm||1480 g||800||Y||Mar 2010||9,995|
|3.||Canon 77D||131 mm||100 mm||76 mm||540 g||600||n||Feb 2017||899|
|4.||Canon T6i||132 mm||101 mm||78 mm||555 g||440||n||Feb 2015||749|
|5.||Canon T6s||132 mm||101 mm||78 mm||565 g||440||n||Feb 2015||649|
|6.||Canon T4i||133 mm||100 mm||79 mm||575 g||440||n||Jun 2012||849|
|7.||Canon 1D X||158 mm||168 mm||83 mm||1551 g||1120||Y||Oct 2011||6,799|
|8.||Canon 1D Mark IV||156 mm||157 mm||80 mm||1230 g||1500||Y||Oct 2009||4,999|
|9.||Canon T1i||129 mm||98 mm||62 mm||520 g||400||n||Mar 2009||799|
|10.||Canon XSi||129 mm||98 mm||62 mm||524 g||500||n||Jan 2008||799|
|11.||Canon 30D||144 mm||106 mm||74 mm||785 g||750||n||Feb 2006||1,399|
|12.||Canon XTi||127 mm||84 mm||65 mm||556 g||370||n||Aug 2006||799|
|13.||Canon 20D||144 mm||106 mm||72 mm||770 g||700||n||Aug 2004||1,499|
|14.||Canon Rebel||142 mm||99 mm||72 mm||649 g||400||n||Aug 2003||899|
|15.||Leica S Typ 006||160 mm||120 mm||80 mm||1260 g||..||Y||Sep 2012||21,950|
|16.||Nikon D3S||160 mm||157 mm||88 mm||1240 g||4200||Y||Oct 2009||5,199|
|17.||Pentax 645Z||156 mm||117 mm||123 mm||1550 g||650||Y||Apr 2014||8,499|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will naturally be influenced heavily by the price. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The XT was launched at a markedly lower price (by 91 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. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixels 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 Canon XT features an APS-C sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 341 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.6 and 0.79. The sensor in the XT 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 XT (8MP), but the 645D has smaller individual pixels (pixel pitch of 6.06μm versus 6.41μm for the XT). Yet, the 645D is a much more recent model (by 5 years) than the XT, 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 XT are 17.3 x 11.5 inches or 43.9 x 29.3 cm for good quality, 13.8 x 9.2 inches or 35.1 x 23.4 cm for very good quality, and 11.5 x 7.7 inches or 29.3 x 19.5 cm for excellent quality prints.
The Canon EOS Rebel XT has a native sensitivity range from ISO 100 to ISO 1600. The Pentax 645D offers exactly the same ISO settings.
Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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"). Of the two cameras under consideration, the 645D offers substantially better image quality than the XT (overall score 22 points higher). The advantage is based on 2.8 bits higher color depth, 1.8 EV in additional dynamic range, and 1 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 |
|2.||Pentax 645D||Medium Format||39.5||7264||5440||none||24.6||12.6||1262||82|
|7.||Canon 1D X||Full Frame||17.9||5184||3456||1080/30p||23.8||11.8||2786||82|
|8.||Canon 1D Mark IV||APS-H||16.0||4896||3264||1080/30p||22.8||12.0||1320||74|
|15.||Leica S Typ 006||Medium Format||37.5||7500||5000||none||23.9||12.2||824||76|
|16.||Nikon D3S||Full Frame||12.1||4256||2832||720/24p||23.5||12.0||3253||82|
|17.||Pentax 645Z||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101|
Beyond body and sensor, cameras can and do differ across a range of features. The XT and the 645D are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The viewfinder in the 645D offers a wider field of view (98%) than the one in the XT (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the 645D has a higher magnification (0.78x vs 0.49x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Canon XT and Pentax 645D in connection with corresponding information for a sample of similar cameras.
|7.||Canon 1D X||optical||Y||3.2||1040||fixed||n||1/8000s||14.0||n||n|
|8.||Canon 1D Mark IV||optical||Y||3.0||920||fixed||n||1/8000s||10.0||n||n|
|15.||Leica S Typ 006||optical||Y||3.0||922||fixed||n||1/4000s||1.5||n||n|
One difference between the cameras concerns the presence of an on-board flash. The XT has one, while the 645D does not. While the built-in flash of the XT is not very powerful, it can at times be useful as a fill-in light.
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 XT writes its imaging data to Compact Flash cards, while the 645D uses SDXC cards. The 645D features dual card slots, which can be very useful in case a memory card fails. In contrast, the XT 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 Canon EOS Rebel XT and Pentax 645D and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|7.||Canon 1D X||Y||mono||-||Y||-||mini||2.0||-||-||-|
|8.||Canon 1D Mark IV||Y||stereo||-||Y||-||mini||2.0||-||-||-|
|15.||Leica S Typ 006||Y||-||-||-||-||mini||2.0||-||-||-|
Studio photographers will appreciate that the Pentax 645D (unlike the XT) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the XT and the 645D have been discontinued, but can regularly be found used on eBay. The XT was replaced by the Canon Xti, while the 645D was followed 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 what conclusions can be drawn? Which of the two cameras – the Canon XT or the Pentax 645D – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.
Reasons to prefer the Canon EOS Rebel XT:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Faster burst: Shoots at higher frequency (3 vs 1.1 flaps/sec) to capture the decisive moment.
- More compact: Is smaller (127x94mm vs 156x117mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 940g or 64 percent) and hence easier to carry around.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- More affordable: Was introduced into a lower priced category (91 percent cheaper at launch).
- More heavily discounted: Has been available for much longer (launched in February 2005).
Advantages of the Pentax 645D:
- More detail: Has more megapixels (39.5 vs 8MP), which boosts linear resolution by 118%.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- Better image quality: Scores substantially higher (22 points) in the DXO overall evaluation.
- Richer colors: Generates noticeably more natural colors (2.8 bits more color depth).
- More dynamic range: Captures a broader range of light and dark details (1.8 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (1 stops ISO advantage).
- More complete view: Has a viewfinder with a larger field of view (98% vs 95%).
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.49x).
- Easier setting verification: Features a control panel on top to check shooting parameters.
- Larger screen: Has a bigger rear LCD (3.0" vs 1.8") for image review and settings control.
- More detailed LCD: Has a higher resolution rear screen (921k vs 115k dots).
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- Longer lasting: Gets more shots (800 versus 400) out of a single battery charge.
- Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
- 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 modern: Reflects 5 years of technical progress since the XT launch.
If the count of individual advantages (bullet points above) is taken as a guide, the 645D is the clear winner of the contest (17 : 7 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 XT and the Pentax 645D 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 says little about, for example, the shooting experience and imaging performance of the XT and the 645D in practical situations. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.
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 XT||..||80/100||+ +||o||..||Feb 2005||899|
|2.||Pentax 645D||5/5||..||..||..||..||Mar 2010||9,995|
|3.||Canon 77D||4.5/5||..||82/100||4.5/5||4/5||Feb 2017||899|
|4.||Canon T6i||5/5||..||75/100||4.5/5||4.5/5||Feb 2015||749|
|5.||Canon T6s||5/5||+||77/100||4.5/5||4.5/5||Feb 2015||649|
|6.||Canon T4i||4/5||+ +||77/100||4.5/5||4.5/5||Jun 2012||849|
|7.||Canon 1D X||5/5||..||..||4.5/5||4.5/5||Oct 2011||6,799|
|8.||Canon 1D Mark IV||5/5||..||89/100||..||..||Oct 2009||4,999|
|9.||Canon T1i||..||+ +||74/100||4.5/5||4.5/5||Mar 2009||799|
|10.||Canon XSi||..||+ +||+ +||4/5||4.5/5||Jan 2008||799|
|11.||Canon 30D||..||+ +||+ +||o||..||Feb 2006||1,399|
|12.||Canon XTi||..||+ +||+ +||o||4/5||Aug 2006||799|
|13.||Canon 20D||..||..||+ +||..||..||Aug 2004||1,499|
|14.||Canon Rebel||..||..||+ +||..||..||Aug 2003||899|
|15.||Leica S Typ 006||..||..||..||..||..||Sep 2012||21,950|
|16.||Nikon D3S||5/5||..||89/100||4.5/5||5/5||Oct 2009||5,199|
|17.||Pentax 645Z||5/5||..||..||4.5/5||5/5||Apr 2014||8,499|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. A score, therefore, has to be seen in close connection to the price and market introduction time 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. 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 make a corresponding selection in the search boxes below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.
Specifications: Canon XT 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 XT||Pentax 645D|
|Camera Type||Digital single lens reflex||Digital single lens reflex|
|Camera Lens||Canon EF mount lenses||Pentax 645 mount lenses|
|Launch Date||February 2005||March 2010|
|Launch Price||USD 899||USD 9,995|
|Sensor Specs||Canon XT||Pentax 645D|
|Sensor Format||APS-C Sensor||Medium Format Sensor|
|Sensor Size||22.2 x 14.8 mm||44.0 x 33.0 mm|
|Sensor Area||328.56 mm2||1452 mm2|
|Sensor Diagonal||26.7 mm||55 mm|
|Sensor Resolution||8 Megapixels||39.5 Megapixels|
|Image Resolution||3456 x 2304 pixels||7264 x 5440 pixels|
|Pixel Pitch||6.41 μm||6.06 μm|
|Pixel Density||2.42 MP/cm2||2.72 MP/cm2|
|Moiré control||Anti-Alias filter||no AA filter|
|Movie Capability||no Video||no Video|
|ISO Setting||100 - 1,600 ISO||100 - 1,600 ISO|
|Image Processor||DIGIC II||PRIME II|
|DXO Sensor Quality (score)||60||82|
|DXO Color Depth (bits)||21.8||24.6|
|DXO Dynamic Range (EV)||10.8||12.6|
|DXO Low Light (ISO)||637||1262|
|Screen Specs||Canon XT||Pentax 645D|
|Viewfinder Type||Optical viewfinder||Optical viewfinder|
|Viewfinder Field of View||95%||98%|
|Top-Level Screen||no Top Display||Control Panel|
|Rear LCD Size||1.8inch||3.0inch|
|LCD Resolution||115k dots||921k dots|
|LCD Attachment||Fixed screen||Fixed screen|
|Shooting Specs||Canon XT||Pentax 645D|
|Focus System||Phase-detect AF||Phase-detect AF|
|Continuous Shooting||3 shutter flaps/s||1.1 shutter flaps/s|
|Shutter Life Expectancy||50 000 actuations||50 000 actuations|
|Time-Lapse Photography||no Intervalometer||Intervalometer built-in|
|Fill Flash||Built-in Flash||no On-Board Flash|
|Storage Medium||CF cards||SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|Connectivity Specs||Canon XT||Pentax 645D|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||no HDMI||no HDMI|
|Wifi Support||no Wifi||no Wifi|
|Body Specs||Canon XT||Pentax 645D|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||400 shots per charge||800 shots per charge|
127 x 94 x 64 mm
(5.0 x 3.7 x 2.5 in)
156 x 117 x 119 mm
(6.1 x 4.6 x 4.7 in)
|Camera Weight||540 g (19.0 oz)||1480 g (52.2 oz)|
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