Pentax 645D vs 645Z

The Pentax 645D and the Pentax 645Z are two professional cameras that were revealed to the public, respectively, in March 2010 and April 2014. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with a medium format sensor. The 645D has a resolution of 39.5 megapixels, whereas the 645Z 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

Pentax 645D		Pentax 645Z
Digital single lens reflex		Digital single lens reflex
Pentax 645 mount lenses		Pentax 645 mount lenses
39.5 MP – Medium Format sensor		51.1 MP – Medium Format sensor
no Video		1080/60i Video
ISO 100-1,600		ISO 100-204,800
Optical viewfinder		Optical viewfinder
3.0" LCD – 921k dots		3.2" LCD – 1037k dots
Fixed screen (not touch-sensitive)		Tilting screen (no touchscreen)
1.1 shutter flaps per second		3 shutter flaps per second
Weathersealed body		Weathersealed body
800 shots per battery charge		650 shots per battery charge
156 x 117 x 119 mm, 1480 g		156 x 117 x 123 mm, 1550 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax 645D 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

The side-by-side display below illustrates the physical size and weight of the Pentax 645D and the Pentax 645Z. 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 width, height and depth dimensions are rounded to the nearest millimeter.

In this particular case, the Pentax 645D and the Pentax 645Z have exactly the same width and height, and, thus, have identically-sized bodies. However, the 645Z is markedly heavier (5 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 table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price	Street Price
1.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	US$ 9 995	ebay.com
2.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	US$ 8 499	ebay.com
3.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	US$ 4 999	ebay.com
4.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	US$ 6 799	ebay.com
5.		Canon 1D X Mark II	158 mm	168 mm	83 mm	1530 g	1210	Y	Feb 2016	US$ 5 999	ebay.com
6.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	US$ 3 699	ebay.com
7.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	US$ 3 699	ebay.com
8.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	US$ 8 995	ebay.com
9.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	US$ 21 949	ebay.com
10.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	US$ 7 449	ebay.com
11.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	US$ 5 199	ebay.com
12.		Nikon D5	160 mm	159 mm	92 mm	1415 g	3780	Y	Jan 2016	US$ 6 499	ebay.com
13.		Nikon D810	146 mm	123 mm	82 mm	980 g	1200	Y	Jun 2014	US$ 3 299	ebay.com
14.		Nikon D850	146 mm	124 mm	79 mm	1005 g	1840	Y	Jul 2017	US$ 3 299	amazon.com
15.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	US$ 2 299	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The 645Z was launched at a somewhat lower price (by 15 percent) than the 645D, which makes it more attractive for photographers on a tight budget. 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 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. 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.

Both cameras under consideration feature a medium format sensor, but their sensors differ slightly in size. The sensor area in the 645Z is 1 percent smaller. They nevertheless have the same format factor of 0.79. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.

Technology-wise, the 645Z uses a more advanced image processing engine (PRIME III) than the 645D (PRIME II), with benefits for noise reduction, color accuracy, and processing speed.

Despite having a slightly smaller sensor, the 645Z offers a higher resolution of 51.1 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 5.30μm versus 6.06μm for the 645D). However, it should be noted that the 645Z is much more recent (by 4 years and 1 month) 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 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 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 Pentax 645D has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Pentax 645Z are ISO 100 to ISO 204800 (no boost).

In terms of underlying technology, the 645D is build around a CCD sensor, while the 645Z uses a CMOS imager. 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 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 645D (overall score 19 points higher). The advantage is based on 1.4 bits higher color depth, 2.1 EV in additional dynamic range, and 1.8 stops in additional low light sensitivity. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
2.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
3.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
4.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
5.		Canon 1D X Mark II	Full Frame	20.0	5472	3648	4K/60p	24.1	13.5	3207	88
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 S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
10.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
11.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
12.		Nikon D5	Full Frame	20.7	5588	3712	4K/30p	25.1	12.3	2343	88
13.		Nikon D810	Full Frame	36.2	7360	4912	1080/60p	25.7	14.8	2853	97
14.		Nikon D850	Full Frame	45.4	8256	5504	4K/30p	26.4	14.8	2660	100
15.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95

Many modern cameras cannot only take still pictures, but also record videos. The 645Z indeed provides for movie recording, while the 645D does not. The highest resolution format that the 645Z can use is 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The 645D 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 viewfinders of both cameras offer the same field of view (98%), as well as the same magnification (0.78x). The adjacent table lists some of the other core features of the Pentax 645D and Pentax 645Z along with similar information for a selection of comparators.

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 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
2.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
3.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
4.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
5.		Canon 1D X Mark II	optical	Y	3.2 / 1620	fixed	Y	1/8000s	16.0/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 S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
10.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
11.		Nikon D3S	optical	Y	3.0 / 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 D810	optical	Y	3.2 / 1229	fixed	n	1/8000s	5.0/s	Y	n
14.		Nikon D850	optical	Y	3.2 / 2359	tilting	Y	1/8000s	9.0/s	n	n
15.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

The Pentax 645D and the Pentax 645Z 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.

Concerning the storage of imaging data, both the 645D and the 645Z write their files to 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 645D 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 645D 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.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
2.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-
3.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
4.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
5.		Canon 1D X Mark II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
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 S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
10.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
11.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
12.		Nikon D5	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
13.		Nikon D810	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
14.		Nikon D850	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
15.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-

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

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

Review summary

So what conclusions can be drawn? Is the Pentax 645D better than the Pentax 645Z or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Pentax 645D:

• Longer lasting: Can take more shots (800 versus 650) on a single battery charge.
• More heavily discounted: Has been available for much longer (launched in March 2010).

Advantages of the Pentax 645Z:

• More detail: Has more megapixels (51.1 vs 39.5MP), which boosts linear resolution by 14%.
• Better image quality: Scores substantially higher (19 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (1.4 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.1 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (1.8 stops ISO advantage).
• Better jpgs: Has a more modern image processing engine (PRIME III vs PRIME II).
• Broader imaging potential: Can capture not only stills but also 1080/60i video.
• 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 921k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Faster burst: Shoots at higher frequency (3 vs 1.1 flaps/sec) to capture the decisive moment.
• 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 affordable: Was released into a lower priced segment (15 percent cheaper at launch).
• More modern: Reflects 4 years and 1 month of technical progress since the 645D launch.

If the count of individual advantages (bullet points above) is taken as a guide, the 645Z is the clear winner of the contest (15 : 2 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 645D 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 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 645Z. 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.

Expert reviews

This is why hands-on reviews by experts 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], 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	Street Price
1.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	US$ 9 995	ebay.com
2.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	US$ 8 499	ebay.com
3.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	US$ 4 999	ebay.com
4.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	US$ 6 799	ebay.com
5.		Canon 1D X Mark II	..	..	4.5/5	89/100	4.5/5	4.5/5	Feb 2016	US$ 5 999	ebay.com
6.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	US$ 3 699	ebay.com
7.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	US$ 3 699	ebay.com
8.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	US$ 8 995	ebay.com
9.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	US$ 21 949	ebay.com
10.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	US$ 7 449	ebay.com
11.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	US$ 5 199	ebay.com
12.		Nikon D5	..	..	4/5	89/100	4.5/5	5/5	Jan 2016	US$ 6 499	ebay.com
13.		Nikon D810	5/5	..	5/5	86/100	5/5	4.5/5	Jun 2014	US$ 3 299	ebay.com
14.		Nikon D850	4.5/5	+ +	5/5	89/100	4.5/5	5/5	Jul 2017	US$ 3 299	amazon.com
15.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	US$ 2 299	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted 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 comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

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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.

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