Pentax 645Z vs Sony RX1

The Pentax 645Z and the Sony Cyber-shot DSC-RX1 are two digital cameras that were revealed to the public, respectively, in April 2014 and September 2012. The 645Z is a DSLR, while the RX1 is a fixed lens compact. The cameras are based on a medium format (645Z) and a full frame (RX1) sensor. The Pentax has a resolution of 51.1 megapixels, whereas the Sony provides 24 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 RX1
Digital single lens reflex		Fixed lens compact camera
Pentax 645 mount lenses		35mm f/2.0
51.1 MP – Medium Format sensor		24 MP – Full Frame sensor
1080/60i Video		1080/60p Video
ISO 100-204,800		ISO 100-25,600 (50 - 102,400)
Optical viewfinder		Viewfinder optional
3.2" LCD – 1037k dots		3.0" LCD – 1229k dots
Tilting screen (no touchscreen)		Fixed screen (not touch-sensitive)
3 shutter flaps per second		5 shutter flaps per second
Weathersealed body		not weather sealed
650 shots per battery charge		270 shots per battery charge
156 x 117 x 123 mm, 1550 g		113 x 65 x 70 mm, 482 g

Check 645Z offers at
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Check RX1 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-RX1? 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 Pentax 645Z and the Sony RX1 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 Sony RX1 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 RX1 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the RX1 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 RX1 can take 270 images on a single charge of its Sony NP-BX1 power pack. The power pack in the RX1 can be charged via the USB port, which can be very convenient when travelling.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.		Sony RX1	113 mm	65 mm	70 mm	482 g	270	n	Sep 2012	2,799	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 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.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	8,995	ebay.com
7.		Leica M11	139 mm	80 mm	39 mm	640 g	700	Y	Jan 2022	8,995	amazon.com
8.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	7,450	ebay.com
9.		Nikon D4S	160 mm	157 mm	91 mm	1350 g	3020	Y	Feb 2014	6,499	ebay.com
10.		Nikon D5	160 mm	159 mm	92 mm	1415 g	3780	Y	Jan 2016	6,499	ebay.com
11.		Nikon D5300	125 mm	98 mm	76 mm	480 g	600	n	Oct 2013	799	ebay.com
12.		Nikon D7200	136 mm	107 mm	76 mm	765 g	1110	Y	Mar 2015	1,199	ebay.com
13.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
14.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	329	ebay.com
15.		Sony NEX-7	120 mm	67 mm	43 mm	400 g	430	n	Aug 2011	1,349	ebay.com
16.		Sony RX1R	113 mm	65 mm	70 mm	482 g	270	n	Jun 2013	2,799	ebay.com
17.		Sony RX1R II	113 mm	65 mm	72 mm	507 g	220	n	Oct 2015	3,299	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 manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The RX1 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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 Sony RX1 a full frame sensor. The sensor area in the RX1 is 41 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 RX1 offers a 3:2 aspect.

With 51.1MP, the 645Z offers a higher resolution than the RX1 (24MP), but the 645Z has smaller individual pixels (pixel pitch of 5.30μm versus 5.96μm for the RX1). However, the 645Z is a somewhat more recent model (by 1 year and 7 months) than the RX1, 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 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 Sony RX1 are 30 x 20 inches or 76.2 x 50.8 cm for good quality, 24 x 16 inches or 61 x 40.6 cm for very good quality, and 20 x 13.3 inches or 50.8 x 33.9 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-RX1 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 has a notably higher overall DXO score than the RX1 (overall score 8 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.9 bits higher color depth, 0.4 EV in additional dynamic range, and 0.8 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.		Sony RX1	Full Frame	24.0	6000	4000	1080/60p	25.1	14.3	2534	93
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 SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
9.		Nikon D4S	Full Frame	16.2	4928	3280	1080/60p	24.4	13.3	3074	89
10.		Nikon D5	Full Frame	20.7	5588	3712	4K/30p	25.1	12.3	2343	88
11.		Nikon D5300	APS-C	24.0	6000	4000	1080/60p	24.0	13.9	1338	83
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 A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
15.		Sony NEX-7	APS-C	24.0	6000	4000	1080/60i	24.1	13.4	1016	81
16.		Sony RX1R	Full Frame	24.0	6000	4000	1080/60p	25.0	13.6	2537	91
17.		Sony RX1R II	Full Frame	42.2	7952	5304	1080/60p	25.8	13.9	3204	97

Many modern cameras are not only capable of taking still images, but can also record movies. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the RX1 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 645Z has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the RX1 relies on live view and the rear LCD for framing. That said, the RX1 can be equipped with an optional viewfinder – the FDA-EV1MK. The adjacent table lists some of the other core features of the Pentax 645Z and Sony RX1 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 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
2.		Sony RX1	optional	n	3.0 / 1229	fixed	n	1/4000s	5.0/s	Y	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 SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
9.		Nikon D4S	optical	Y	3.2 / 921	fixed	n	1/8000s	11.0/s	n	n
10.		Nikon D5	optical	Y	3.2 / 2359	fixed	Y	1/8000s	14.0/s	n	n
11.		Nikon D5300	optical	n	3.2 / 1037	swivel	n	1/4000s	5.0/s	Y	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 A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
15.		Sony NEX-7	2359	n	3.0 / 921	tilting	n	1/4000s	10.0/s	Y	n
16.		Sony RX1R	optional	n	3.0 / 1229	fixed	n	1/4000s	5.0/s	Y	n
17.		Sony RX1R II	2360	n	3.0 / 1229	tilting	n	1/4000s	5.0/s	n	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 RX1 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 RX1 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 RX1 only has one slot. The 645Z supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the RX1 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 Sony Cyber-shot DSC-RX1 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 RX1	Y	stereo / mono	Y	-	mini	2.0	-	-	-
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 SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
9.		Nikon D4S	Y	mono / mono	Y	Y	mini	2.0	-	-	-
10.		Nikon D5	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
11.		Nikon D5300	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
12.		Nikon D7200	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
13.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
14.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
15.		Sony NEX-7	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Sony RX1R	Y	stereo / mono	Y	-	mini	2.0	-	-	-
17.		Sony RX1R II	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-

Studio photographers will appreciate that the Pentax 645Z (unlike the RX1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 645Z and the RX1 have been discontinued, but can regularly be found used on ebay. The RX1 was replaced by the Sony RX1R, while the 645Z does not have a direct successor. Further information on the features and operation of the 645Z and RX1 can be found, respectively, in the Pentax 645Z Manual (free pdf) or the online Sony RX1 Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Pentax 645Z or the Sony RX1 – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Pentax 645Z:

• More detail: Offers more megapixels (51.1 vs 24MP) with a 43% higher linear resolution.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores markedly higher (8 points) in the DXO overall assessment.
• Better low-light sensitivity: Requires less light for good images (0.8 stops ISO advantage).
• Easier framing: Has an optical viewfinder for image composition and settings control.
• 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.
• 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.
• More flexible: Can take a variety of interchangeable lenses, including specialty optics.
• Longer lasting: Can take more shots (650 versus 270) 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.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Is somewhat more recent (announced 1 year and 7 months after the RX1).

Arguments in favor of the Sony Cyber-shot DSC-RX1:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
• 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 fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More heavily discounted: Has been on the market for longer (launched in September 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 (17 : 11 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 RX1 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 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 645Z or the RX1 perform in practice. 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 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.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	ebay.com
2.		Sony RX1	5/5	..	..	79/100	4/5	4.5/5	Sep 2012	2,799	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 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.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	8,995	ebay.com
7.		Leica M11	4.5/5	..	4.5/5	..	4.5/5	4.5/5	Jan 2022	8,995	amazon.com
8.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	7,450	ebay.com
9.		Nikon D4S	5/5	..	..	..	4.5/5	4.5/5	Feb 2014	6,499	ebay.com
10.		Nikon D5	..	..	4/5	89/100	4.5/5	5/5	Jan 2016	6,499	ebay.com
11.		Nikon D5300	4/5	+ +	..	79/100	4.5/5	4.5/5	Oct 2013	799	ebay.com
12.		Nikon D7200	4/5	+ +	..	84/100	4.5/5	4.5/5	Mar 2015	1,199	ebay.com
13.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
14.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	329	ebay.com
15.		Sony NEX-7	5/5	+ +	..	81/100	4.5/5	5/5	Aug 2011	1,349	ebay.com
16.		Sony RX1R	5/5	..	..	..	4/5	4.5/5	Jun 2013	2,799	ebay.com
17.		Sony RX1R II	5/5	..	..	82/100	..	4.5/5	Oct 2015	3,299	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, 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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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? In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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