Pentax 645Z vs Canon 5D Mark III

The Pentax 645Z and the Canon EOS 5D Mark III are two professional cameras that were officially introduced, respectively, in April 2014 and March 2012. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a medium format (645Z) and a full frame (5D Mark III) sensor. The Pentax has a resolution of 51.1 megapixels, whereas the Canon provides 22.1 MP.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Pentax 645Z		Canon 5D Mark III
Digital single lens reflex		Digital single lens reflex
Pentax 645 mount lenses		Canon EF mount lenses
51.1 MP – Medium Format sensor		22.1 MP – Full Frame sensor
1080/60i Video		1080/30p Video
ISO 100-204,800		ISO 100-25,600 (50 - 102,400)
Optical viewfinder		Optical viewfinder
3.2" LCD – 1037k dots		3.2" LCD – 1040k dots
Tilting screen (no touchscreen)		Fixed screen (not touch-sensitive)
3 shutter flaps per second		6 shutter flaps per second
Weathersealed body		Weathersealed body
650 shots per battery charge		950 shots per battery charge
156 x 117 x 123 mm, 1550 g		152 x 116 x 76 mm, 950 g

Check 645Z offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax 645Z and the Canon EOS 5D Mark III? 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.

Body comparison

The physical size and weight of the Pentax 645Z and the Canon 5D Mark III 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 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 Canon 5D Mark III is somewhat smaller (3 percent) than the Pentax 645Z. Moreover, the 5D Mark III is substantially lighter (39 percent) than the 645Z. 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 645Z gets 650 shots out of its Pentax D-LI90 battery, while the 5D Mark III can take 950 images on a single charge of its Canon LP-E6 power pack.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price (USD)	Street Price
1.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	8,499	ebay.com
2.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
3.		Canon 1D X Mark II	158 mm	168 mm	83 mm	1530 g	1210	Y	Feb 2016	5,999	ebay.com
4.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
5.		Canon 5D Mark IV	151 mm	116 mm	76 mm	890 g	900	Y	Aug 2016	3,499	amazon.com
6.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
7.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
8.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	8,995	ebay.com
9.		Leica M11	139 mm	80 mm	39 mm	640 g	700	Y	Jan 2022	8,995	amazon.com
10.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	7,450	ebay.com
11.		Nikon D4S	160 mm	157 mm	91 mm	1350 g	3020	Y	Feb 2014	6,499	ebay.com
12.		Nikon D5	160 mm	159 mm	92 mm	1415 g	3780	Y	Jan 2016	6,499	ebay.com
13.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
14.		Nikon D7200	136 mm	107 mm	76 mm	765 g	1110	Y	Mar 2015	1,199	ebay.com
15.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
Convert to Imperial

Any camera decision will obviously take relative prices into account. 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 5D Mark III was launched at a markedly lower price (by 59 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.

Sensor comparison

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 645Z features a medium format sensor and the Canon 5D Mark III a full frame sensor. The sensor area in the 5D Mark III is 40 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 645Z has a native 4:3 aspect ratio, while the one in the 5D Mark III offers a 3:2 aspect.

With 51.1MP, the 645Z offers a higher resolution than the 5D Mark III (22.1MP), but the 645Z has smaller individual pixels (pixel pitch of 5.30μm versus 6.25μm for the 5D Mark III). However, the 645Z is a much more recent model (by 2 years and 1 month) than the 5D Mark III, and its sensor will have benefitted from technological advances during this time that 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 Canon 5D Mark III are 28.8 x 19.2 inches or 73.2 x 48.8 cm for good quality, 23 x 15.4 inches or 58.5 x 39 cm for very good quality, and 19.2 x 12.8 inches or 48.8 x 32.5 cm for excellent quality prints.

The Pentax 645Z has a native sensitivity range from ISO 100 to ISO 204800. The corresponding ISO settings for the Canon EOS 5D Mark III are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-102400.

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 review, the 645Z provides substantially higher image quality than the 5D Mark III, with an overall score that is 20 points higher. This advantage is based on 2 bits higher color depth, 3 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.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
2.		Canon 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
3.		Canon 1D X Mark II	Full Frame	20.0	5472	3648	4K/60p	24.1	13.5	3207	88
4.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
5.		Canon 5D Mark IV	Full Frame	30.1	6720	4480	4K/30p	24.8	13.6	2995	91
6.		Canon 5DS	Full Frame	50.3	8688	5792	1080/30p	24.7	12.4	2381	87
7.		Canon 5DS R	Full Frame	50.3	8688	5792	1080/30p	24.6	12.4	2308	86
8.		Hasselblad X1D	Medium Format	51.3	8272	6200	1080/25p	26.2	14.8	4489	102
9.		Leica M11	Full Frame	60.3	9528	6328	none	26.3	14.8	3376	100
10.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
11.		Nikon D4S	Full Frame	16.2	4928	3280	1080/60p	24.4	13.3	3074	89
12.		Nikon D5	Full Frame	20.7	5588	3712	4K/30p	25.1	12.3	2343	88
13.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
14.		Nikon D7200	APS-C	24.0	6000	4000	1080/60p	24.5	14.6	1333	87
15.		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. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the 645Z provides a higher frame rate than the 5D Mark III. It can shoot video footage at 1080/60i, while the Canon is limited to 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The 645Z and the 5D Mark III 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 5D Mark III 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 0.71x), 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 Pentax 645Z and Canon 5D Mark III in connection with corresponding information for a sample of similar cameras.

Core Features

		Camera Model	Viewfinder (Type or 000 dots)	Control Panel (yes/no)	LCD Specifications (inch/000 dots)	LCD Attach- ment	Touch Screen (yes/no)	Max Shutter Speed *	Max Shutter Flaps *	Built-in Flash (yes/no)	Built-in Image Stab
1.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
2.		Canon 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
3.		Canon 1D X Mark II	optical	Y	3.2 / 1620	fixed	Y	1/8000s	16.0/s	n	n
4.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
5.		Canon 5D Mark IV	optical	Y	3.2 / 1620	fixed	Y	1/8000s	7.0/s	n	n
6.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
7.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
8.		Hasselblad X1D	2360	n	3.0 / 920	fixed	Y	1/2000s	2.3/s	n	n
9.		Leica M11	optical	n	3.0 / 2333	fixed	Y	1/4000s	4.5/s	n	n
10.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
11.		Nikon D4S	optical	Y	3.2 / 921	fixed	n	1/8000s	11.0/s	n	n
12.		Nikon D5	optical	Y	3.2 / 2359	fixed	Y	1/8000s	14.0/s	n	n
13.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
14.		Nikon D7200	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
15.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

The Pentax 645Z 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 645Z writes its imaging data to SDXC cards, while the 5D Mark III uses Compact Flash or SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. The 645Z supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the 5D Mark III cannot take advantage of Ultra High Speed SD cards.

Connectivity comparison

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 Canon EOS 5D Mark III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

Input-Output Connections

		Camera Model	Hotshoe Port	Internal Mic / Speaker	Microphone Port	Headphone Port	HDMI Port	USB Port	WiFi Support	NFC Support	Bluetooth Support
1.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-
2.		Canon 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
3.		Canon 1D X Mark II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
4.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
5.		Canon 5D Mark IV	Y	mono / mono	Y	Y	mini	3.0	Y	Y	-
6.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
7.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
8.		Hasselblad X1D	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
9.		Leica M11	Y	- / -	-	-	-	3.2	Y	-	Y
10.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
11.		Nikon D4S	Y	mono / mono	Y	Y	mini	2.0	-	-	-
12.		Nikon D5	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
13.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
14.		Nikon D7200	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
15.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-

It is notable that the 5D Mark III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The 645Z lacks such a headphone port.

Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.

Both the 645Z and the 5D Mark III have been discontinued, but can regularly be found used on ebay. The 5D Mark III was replaced by the Canon 5D Mark IV, while the 645Z does not have a direct successor. Further information on the features and operation of the 645Z and 5D Mark III can be found, respectively, in the Pentax 645Z Manual (free pdf) or the online Canon 5D Mark III Manual.

Review summary

So what is the bottom line? Is there a clear favorite between the Pentax 645Z and the Canon 5D Mark III? Which camera is better? The listing below highlights the relative strengths of the two models.

Advantages of the Pentax 645Z:

• More detail: Offers more megapixels (51.1 vs 22.1MP) with a 49% higher linear resolution.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (20 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (2 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (3 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (1 stops ISO advantage).
• Better video: Provides higher movie framerates (1080/60i versus 1080/30p).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.71x).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Reflects 2 years and 1 month of technical progress since the 5D Mark III launch.

Reasons to prefer the Canon EOS 5D Mark III:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• More complete view: Has a viewfinder with a larger field of view (100% vs 98%).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (6 vs 3 flaps/sec) to capture the decisive moment.
• Less heavy: Has a lower weight (by 600g or 39 percent) and is thus easier to take along.
• Longer lasting: Gets more shots (950 versus 650) out of a single battery charge.
• More affordable: Was introduced into a lower priced category (59 percent cheaper at launch).
• More heavily discounted: Has been around for much longer (launched in March 2012).

If the count of individual advantages (bullet points above) is taken as a guide, the 645Z is the clear winner of the match-up (13 : 9 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. 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 645Z and the Canon 5D Mark III 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 incomplete and does no justice, for example, to the way the 645Z or the 5D Mark III perform in practice. 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.

Expert reviews

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 (amateurphotographer [AP], cameralabs [CL], digitalcameraworld [DCW], 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.

Expert Camera Reviews

		Camera   Model	AP   score	CL   score	DCW   score	DPR   score	EPZ   score	PB   score	Camera Launch	Launch Price (USD)	Street Price
1.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	ebay.com
2.		Canon 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
3.		Canon 1D X Mark II	..	..	4.5/5	89/100	4.5/5	4.5/5	Feb 2016	5,999	ebay.com
4.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
5.		Canon 5D Mark IV	4.5/5	+ +	4/5	87/100	4.5/5	4.5/5	Aug 2016	3,499	amazon.com
6.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	3,699	ebay.com
7.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	3,699	ebay.com
8.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	8,995	ebay.com
9.		Leica M11	4.5/5	..	4.5/5	..	4.5/5	4.5/5	Jan 2022	8,995	amazon.com
10.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	7,450	ebay.com
11.		Nikon D4S	5/5	..	..	..	4.5/5	4.5/5	Feb 2014	6,499	ebay.com
12.		Nikon D5	..	..	4/5	89/100	4.5/5	5/5	Jan 2016	6,499	ebay.com
13.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
14.		Nikon D7200	4/5	+ +	..	84/100	4.5/5	4.5/5	Mar 2015	1,199	ebay.com
15.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
Note: (+ +) 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. Hence, a score should always be seen in the context of the camera's market launch date and its price, 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.

Check 645Z offers at
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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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.

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