Pentax 645Z vs Sony RX1R II

The Pentax 645Z and the Sony Cyber-shot DSC-RX1R II are two digital cameras that were officially introduced, respectively, in April 2014 and October 2015. The 645Z is a DSLR, while the RX1R II is a fixed lens compact. The cameras are based on a medium format (645Z) and a full frame (RX1R II) sensor. The Pentax has a resolution of 51.1 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.

Headline Specifications

Pentax 645Z		Sony RX1R II
Digital single lens reflex		Fixed lens compact camera
Pentax 645 mount lenses		35mm f/2.0
51.1 MP – Medium Format sensor		42.2 MP – Full Frame sensor
1080/60i Video		1080/60p Video
ISO 100-204,800		ISO 100-25,600 (50 - 102,400)
Optical viewfinder		Electronic viewfinder (2360k dots)
3.2" LCD – 1037k dots		3.0" LCD – 1229k dots
Tilting screen (no touchscreen)		Tilting screen (no touchscreen)
3 shutter flaps per second		5 shutter flaps per second
Weathersealed body		not weather sealed
650 shots per battery charge		220 shots per battery charge
156 x 117 x 123 mm, 1550 g		113 x 65 x 72 mm, 507 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 Sony Cyber-shot DSC-RX1R 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.

Body comparison

The physical size and weight of the Pentax 645Z and the Sony RX1R II are illustrated 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 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 RX1R II is considerably smaller (60 percent) than the Pentax 645Z. It is worth mentioning in this context that the 645Z is splash and dust resistant, while the RX1R II does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the RX1R II has a lens built in, whereas the 645Z is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.

Concerning battery life, the 645Z gets 650 shots out of its Pentax D-LI90 battery, while the RX1R II can take 220 images on a single charge of its Sony NP-BX1 power pack. The power pack in the RX1R II can be charged via the USB port, which can be very convenient when travelling.

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 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	US$ 8 499	ebay.com
2.		Sony RX1R II	113 mm	65 mm	72 mm	507 g	220	n	Oct 2015	US$ 3 299	ebay.com
3.		Canon 1D X Mark II	158 mm	168 mm	83 mm	1530 g	1210	Y	Feb 2016	US$ 5 999	ebay.com
4.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	US$ 3 699	ebay.com
5.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	US$ 3 699	ebay.com
6.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	US$ 8 995	ebay.com
7.		Leica M11	139 mm	80 mm	39 mm	640 g	700	Y	Jan 2022	US$ 8 999	amazon.com
8.		Leica Q Typ 116	130 mm	80 mm	93 mm	640 g	300	n	Jun 2015	US$ 4 249	ebay.com
9.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	US$ 7 449	ebay.com
10.		Nikon D4S	160 mm	157 mm	91 mm	1350 g	3020	Y	Feb 2014	US$ 6 499	ebay.com
11.		Nikon D5	160 mm	159 mm	92 mm	1415 g	3780	Y	Jan 2016	US$ 6 499	ebay.com
12.		Nikon D7200	136 mm	107 mm	76 mm	765 g	1110	Y	Mar 2015	US$ 1 199	ebay.com
13.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	US$ 9 995	ebay.com
14.		Sony RX1	113 mm	65 mm	70 mm	482 g	270	n	Sep 2012	US$ 2 799	ebay.com
15.		Sony RX1R	113 mm	65 mm	70 mm	482 g	270	n	Jun 2013	US$ 2 799	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 RX1R II was launched at a lower price than the 645Z, despite having a lens built in. 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 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. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to 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 Sony RX1R II a full frame sensor. The sensor area in the RX1R II 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 RX1R II offers a 3:2 aspect.

With 51.1MP, the 645Z offers a higher resolution than the RX1R II (42.2MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 4.50μm for the RX1R II) due to its larger sensor. However, the RX1R II is a somewhat more recent model (by 1 year and 5 months) than the 645Z, and its sensor might 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 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 Sony RX1R II are 39.8 x 26.5 inches or 101 x 67.4 cm for good quality, 31.8 x 21.2 inches or 80.8 x 53.9 cm for very good quality, and 26.5 x 17.7 inches or 67.3 x 44.9 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 Sony Cyber-shot DSC-RX1R II are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-102400.

In terms of underlying technology, the 645Z is build around a CMOS sensor, while the RX1R II uses a BSI-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.

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 review, the 645Z has a notably higher overall DXO score than the RX1R II (overall score 4 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.2 bits higher color depth, 0.8 EV in additional dynamic range, and 0.5 stops in additional low light sensitivity. The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar 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 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
2.		Sony RX1R II	Full Frame	42.2	7952	5304	1080/60p	25.8	13.9	3204	97
3.		Canon 1D X Mark II	Full Frame	20.0	5472	3648	4K/60p	24.1	13.5	3207	88
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.		Hasselblad X1D	Medium Format	51.3	8272	6200	1080/25p	26.2	14.8	4489	102
7.		Leica M11	Full Frame	60.3	9528	6328	none	26.3	14.8	3376	100
8.		Leica Q Typ 116	Full Frame	24.0	6000	4000	1080/60p	24.3	12.7	2221	85
9.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
10.		Nikon D4S	Full Frame	16.2	4928	3280	1080/60p	24.4	13.3	3074	89
11.		Nikon D5	Full Frame	20.7	5588	3712	4K/30p	25.1	12.3	2343	88
12.		Nikon D7200	APS-C	24.0	6000	4000	1080/60p	24.5	14.6	1333	87
13.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
14.		Sony RX1	Full Frame	24.0	6000	4000	1080/60p	25.1	14.3	2534	93
15.		Sony RX1R	Full Frame	24.0	6000	4000	1080/60p	25.0	13.6	2537	91

Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the RX1R II provides a faster frame rate than the 645Z. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the RX1R II has an electronic viewfinder (2360k dots), while the 645Z 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 viewfinder in the RX1R II 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 0.74x), 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 Sony RX1R II 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.		Sony RX1R II	2360	n	3.0 / 1229	tilting	n	1/4000s	5.0/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 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.		Hasselblad X1D	2360	n	3.0 / 920	fixed	Y	1/2000s	2.3/s	n	n
7.		Leica M11	optical	n	3.0 / 2333	fixed	Y	1/4000s	4.5/s	n	n
8.		Leica Q Typ 116	3680	n	3.0 / 1040	fixed	Y	1/2000s	10.0/s	n	Y
9.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
10.		Nikon D4S	optical	Y	3.2 / 921	fixed	n	1/8000s	11.0/s	n	n
11.		Nikon D5	optical	Y	3.2 / 2359	fixed	Y	1/8000s	14.0/s	n	n
12.		Nikon D7200	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
13.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
14.		Sony RX1	optional	n	3.0 / 1229	fixed	n	1/4000s	5.0/s	Y	n
15.		Sony RX1R	optional	n	3.0 / 1229	fixed	n	1/4000s	5.0/s	Y	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the 645Z, but is missing on the RX1R II is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

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 RX1R II uses SDXC or Memory Stick PRO Duo cards. The 645Z features dual card slots, which can be very useful in case a memory card fails. In contrast, the RX1R II only has one slot. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.

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 Sony Cyber-shot DSC-RX1R II 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.		Sony RX1R II	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
3.		Canon 1D X Mark II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
4.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
5.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
6.		Hasselblad X1D	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
7.		Leica M11	Y	- / -	-	-	-	3.2	Y	-	Y
8.		Leica Q Typ 116	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
9.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
10.		Nikon D4S	Y	mono / mono	Y	Y	mini	2.0	-	-	-
11.		Nikon D5	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
12.		Nikon D7200	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
13.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
14.		Sony RX1	Y	stereo / mono	Y	-	mini	2.0	-	-	-
15.		Sony RX1R	Y	stereo / mono	Y	-	mini	2.0	-	-	-

It is notable that the RX1R II offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the 645Z does not provide wifi capability.

Studio photographers will appreciate that the Pentax 645Z (unlike the RX1R II) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 645Z and the RX1R II have been discontinued, but can regularly be found used on ebay. Neither of the two has a direct successor, so they represent the end of the respective camera lines from Pentax and Sony. Further information on the features and operation of the 645Z and RX1R II can be found, respectively, in the Pentax 645Z Manual (free pdf) or the online Sony RX1R II Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Pentax 645Z or the Sony RX1R II – 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 Pentax 645Z:

• More detail: Offers more megapixels (51.1 vs 42.2MP) with a 8% higher linear resolution.
• Better image quality: Scores markedly higher (4 points) in the DXO overall assessment.
• More dynamic range: Captures a larger spectrum of light and dark details (0.8 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (0.5 stops ISO advantage).
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.74x).
• Easier setting verification: Features an LCD display on top to control shooting parameters.
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More flexible: Can take a variety of interchangeable lenses, including specialty optics.
• Longer lasting: Can take more shots (650 versus 220) on a single battery charge.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
• 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 heavily discounted: Has been on the market for longer (launched in April 2014).

Advantages of the Sony Cyber-shot DSC-RX1R II:

• Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
• 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 1037k dots).
• Faster burst: Shoots at higher frequency (5 vs 3 flaps/sec) to capture the decisive moment.
• Ready to shoot: Comes with an integrated lens, while the 645Z requires a separate lens.
• More compact: Is smaller (113x65mm vs 156x117mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight even though it has a lens built in (unlike the 645Z).
• Easier travel charging: Can be conveniently charged via its USB port.
• 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.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More modern: Was introduced somewhat (1 year and 5 months) more recently.

If the number of relative strengths (bullet points above) is taken as a guide, the 645Z emerges as the winner of the contest (16 : 13 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 Pentax 645Z and the Sony RX1R II place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Prime Lens Compact Camera listings whether the two cameras rank among the cream of the crop.

In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the 645Z or the RX1R II 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 why expert reviews are important. The following table reports the overall ratings of the cameras as published by some of the major 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	Street Price
1.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	US$ 8 499	ebay.com
2.		Sony RX1R II	5/5	..	..	82/100	..	4.5/5	Oct 2015	US$ 3 299	ebay.com
3.		Canon 1D X Mark II	..	..	4.5/5	89/100	4.5/5	4.5/5	Feb 2016	US$ 5 999	ebay.com
4.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	US$ 3 699	ebay.com
5.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	US$ 3 699	ebay.com
6.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	US$ 8 995	ebay.com
7.		Leica M11	4.5/5	..	4.5/5	..	4.5/5	4.5/5	Jan 2022	US$ 8 999	amazon.com
8.		Leica Q Typ 116	5/5	..	..	80/100	4.5/5	4.5/5	Jun 2015	US$ 4 249	ebay.com
9.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	US$ 7 449	ebay.com
10.		Nikon D4S	5/5	..	..	..	4.5/5	4.5/5	Feb 2014	US$ 6 499	ebay.com
11.		Nikon D5	..	..	4/5	89/100	4.5/5	5/5	Jan 2016	US$ 6 499	ebay.com
12.		Nikon D7200	4/5	+ +	..	84/100	4.5/5	4.5/5	Mar 2015	US$ 1 199	ebay.com
13.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	US$ 9 995	ebay.com
14.		Sony RX1	5/5	..	..	79/100	4/5	4.5/5	Sep 2012	US$ 2 799	ebay.com
15.		Sony RX1R	5/5	..	..	..	4/5	4.5/5	Jun 2013	US$ 2 799	ebay.com
Note: (+ +) 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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

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Other camera comparisons

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