Canon 5D Mark III vs Pentax 645Z

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

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

Headline Specifications

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

Check 5D Mark III offers at
ebay.com
Check 645Z price at
amazon.com

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

An illustration of the physical size and weight of the Canon 5D Mark III and the Pentax 645Z is provided in the side-by-side display below. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth 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 Pentax 645Z is somewhat larger (4 percent) than the Canon 5D Mark III. Moreover, the 645Z is substantially heavier (63 percent) than the 5D Mark III. 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 5D Mark III gets 950 shots out of its LP-E6 battery, while the 645Z can take 650 images on a single charge of its D-LI90 power pack.

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

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price (USD)	Street Price
1.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
2.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	8,499	amazon.com
3.		Canon 5D Mark IV	151 mm	116 mm	76 mm	890 g	900	Y	Aug 2016	3,499	amazon.com
4.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
5.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
6.		Canon 6D	145 mm	111 mm	71 mm	770 g	1090	Y	Sep 2012	2,099	ebay.com
7.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
8.		Canon 5D	152 mm	113 mm	75 mm	895 g	400	Y	Aug 2005	3,299	ebay.com
9.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	8,995	ebay.com
10.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	7,450	ebay.com
11.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
12.		Nikon D600	141 mm	113 mm	82 mm	850 g	900	Y	Sep 2012	2,099	ebay.com
13.		Nikon D800	146 mm	123 mm	82 mm	1000 g	900	Y	Feb 2012	2,999	ebay.com
14.		Nikon D800E	146 mm	123 mm	82 mm	1000 g	900	Y	Feb 2012	3,299	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

The price is, of course, an important factor in any camera decision. 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. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 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. 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 tend to be associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Canon 5D Mark III features a full frame sensor and the Pentax 645Z a medium format sensor. The sensor area in the 645Z is 66 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 0.79. The sensor in the 5D Mark III has a native 3:2 aspect ratio, while the one in the 645Z offers a 4:3 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). Yet, 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 pixel-units. 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 Canon EOS 5D Mark III has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 50-102400. The corresponding ISO settings for the Pentax 645Z are ISO 100 to ISO 204800 (no boost).

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.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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. Of the two cameras under consideration, the 645Z offers substantially better image quality than the 5D Mark III (overall score 20 points higher). The 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.		Canon 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
2.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
3.		Canon 5D Mark IV	Full Frame	30.1	6720	4480	4K/30p	24.8	13.6	2995	91
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
6.		Canon 6D	Full Frame	20.0	5472	3648	1080/30p	23.8	12.1	2340	82
7.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
8.		Canon 5D	Full Frame	12.7	4368	2912	none	22.9	11.1	1368	71
9.		Hasselblad X1D	Medium Format	51.3	8272	6200	1080/25p	26.2	14.8	4489	102
10.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
11.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
12.		Nikon D600	Full Frame	24.2	6016	4016	1080/30p	25.1	14.2	2980	94
13.		Nikon D800	Full Frame	36.2	7360	4912	1080/30p	25.3	14.4	2853	95
14.		Nikon D800E	Full Frame	36.2	7360	4912	1080/30p	25.6	14.3	2979	96
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. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the 645Z provides a faster frame rate than the 5D Mark III. It can shoot movie 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 range of features. The 5D Mark III and the 645Z 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 following table reports on some other key feature differences and similarities of the Canon 5D Mark III, the Pentax 645Z, and comparable 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.		Canon 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
2.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
3.		Canon 5D Mark IV	optical	Y	3.2 / 1620	fixed	Y	1/8000s	7.0/s	n	n
4.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
5.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
6.		Canon 6D	optical	Y	3.0 / 1040	fixed	n	1/4000s	4.5/s	n	n
7.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
8.		Canon 5D	optical	Y	2.5 / 230	fixed	n	1/8000s	3.0/s	n	n
9.		Hasselblad X1D	2360	n	3.0 / 920	fixed	Y	1/2000s	2.3/s	n	n
10.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
11.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
12.		Nikon D600	optical	Y	3.0 / 921	fixed	n	1/4000s	5.5/s	Y	n
13.		Nikon D800	optical	Y	3.2 / 921	fixed	n	1/8000s	4.0/s	Y	n
14.		Nikon D800E	optical	Y	3.2 / 921	fixed	n	1/8000s	4.0/s	Y	n
15.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
Notes: *) 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 5D Mark III writes its imaging data to Compact Flash or SDXC cards, while the 645Z uses 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 Canon EOS 5D Mark III and Pentax 645Z 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.		Canon 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
2.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-
3.		Canon 5D Mark IV	Y	mono / mono	Y	Y	mini	3.0	Y	Y	-
4.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
5.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
6.		Canon 6D	Y	mono / mono	Y	-	mini	2.0	Y	-	-
7.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
8.		Canon 5D	Y	- / -	-	-	-	2.0	-	-	-
9.		Hasselblad X1D	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
10.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
11.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
12.		Nikon D600	Y	mono / mono	Y	Y	mini	2.0	-	-	-
13.		Nikon D800	Y	mono / mono	Y	Y	mini	3.0	-	-	-
14.		Nikon D800E	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-

It is notable that the 5D Mark III has a headphone jack, which is not present on the 645Z This port makes it possible to attach external headphones and monitor the quality of sound during the recording process.

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

The 645Z is a recent model that features in the current product line-up of Pentax. In contrast, the 5D Mark III has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the 5D Mark III was succeeded by the Canon 5D Mark IV. Further information on the features and operation of the 5D Mark III and 645Z can be found, respectively, in the Canon 5D Mark III Manual (free pdf) or the online Pentax 645Z Manual.

Review summary

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

Arguments in favor of 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: Is lighter (by 600g or 39 percent) and hence easier to carry around.
• Longer lasting: Can take more shots (950 versus 650) on a single battery charge.
• More affordable: Was introduced into a lower priced category (59 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in March 2012).

Reasons to prefer the Pentax 645Z:

• More detail: Has more megapixels (51.1 vs 22.1MP), which boosts linear resolution by 49%.
• 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 evaluation.
• Richer colors: Generates noticeably more natural colors (2 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (3 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (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.

If the count of individual advantages (bullet points above) is taken as a guide, the 645Z is the clear winner of the contest (13 : 9 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 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 5D Mark III and the Pentax 645Z 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 technical specifications can provide a useful overview of the capabilities of different cameras, it remains incomplete and does no justice, for example, to the way the 5D Mark III or the 645Z perform in practice. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.

Expert reviews

This is where reviews by experts come in. The table below provides a synthesis of the camera assessments of some of the best known photo-gear 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.		Canon 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
2.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	amazon.com
3.		Canon 5D Mark IV	4.5/5	+ +	4/5	87/100	4.5/5	4.5/5	Aug 2016	3,499	amazon.com
4.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	3,699	ebay.com
5.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	3,699	ebay.com
6.		Canon 6D	5/5	+ +	..	83/100	4.5/5	4.5/5	Sep 2012	2,099	ebay.com
7.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
8.		Canon 5D	..	88/100	..	+ +	o	..	Aug 2005	3,299	ebay.com
9.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	8,995	ebay.com
10.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	7,450	ebay.com
11.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
12.		Nikon D600	4/5	+ +	..	87/100	5/5	4.5/5	Sep 2012	2,099	ebay.com
13.		Nikon D800	5/5	+ +	..	82/100	5/5	5/5	Feb 2012	2,999	ebay.com
14.		Nikon D800E	..	..	..	84/100	5/5	5/5	Feb 2012	3,299	ebay.com
15.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
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. A score, therefore, has to be seen in close connection to the price and market introduction time 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.

Check 5D Mark III offers at
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Check 645Z price at
amazon.com

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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