Pentax Q vs 645Z

The Pentax Q and the Pentax 645Z are two digital cameras that were announced, respectively, in June 2011 and April 2014. The Pentax Q is a mirrorless interchangeable lens camera, while the 645Z is a DSLR. The cameras are based on a 1/2.3-inch (Pentax Q) and a medium format (645Z) sensor. The Pentax Q has a resolution of 12 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 Q		Pentax 645Z
Mirrorless system camera		Digital single lens reflex
Pentax Q mount lenses		Pentax 645 mount lenses
12 MP – 1/2.3" sensor		51.1 MP – Medium Format sensor
1080/30p Video		1080/60i Video
ISO 125-6,400		ISO 100-204,800
Viewfinder optional		Optical viewfinder
3.0" LCD – 460k dots		3.2" LCD – 1037k dots
Fixed screen (not touch-sensitive)		Tilting screen (no touchscreen)
1.5 shutter flaps per second		3 shutter flaps per second
In-body stabilization		Lens stabilization only
not weather sealed		Weathersealed body
230 shots per battery charge		650 shots per battery charge
98 x 57 x 31 mm, 180 g		156 x 117 x 123 mm, 1550 g

Check Pentax Q offers at
ebay.com
Check 645Z offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax Q 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 Pentax Q and the Pentax 645Z is provided 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 width, height and depth measures are rounded to the nearest millimeter.

The Pentax Q can be obtained in two different colors (black, white), while the 645Z is only available in black.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax 645Z is considerably larger (227 percent) than the Pentax Q. Moreover, the 645Z is substantially heavier (761 percent) than the Pentax Q. It is noteworthy in this context that the 645Z is splash and dust-proof, while the Pentax Q does not feature any corresponding weather-sealing.

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 following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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 (USD)	Street Price
1.		Pentax Q	98 mm	57 mm	31 mm	180 g	230	n	Jun 2011	649	ebay.com
2.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	8,499	ebay.com
3.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
4.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
5.		Fujifilm X10	117 mm	70 mm	57 mm	350 g	270	n	Sep 2011	599	ebay.com
6.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	8,995	ebay.com
7.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	7,450	ebay.com
8.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	699	ebay.com
9.		Olympus E-P3	122 mm	69 mm	34 mm	369 g	330	n	Jun 2011	799	ebay.com
10.		Olympus E-PL1	115 mm	72 mm	42 mm	334 g	290	n	Feb 2010	599	ebay.com
11.		Olympus E-PL2	114 mm	72 mm	42 mm	362 g	280	n	Jan 2011	599	ebay.com
12.		Olympus E-PL3	110 mm	64 mm	37 mm	313 g	300	n	Jun 2011	599	ebay.com
13.		Olympus XZ-2	113 mm	65 mm	48 mm	346 g	340	n	Sep 2012	599	ebay.com
14.		Panasonic G2	124 mm	84 mm	74 mm	428 g	360	n	Mar 2010	599	ebay.com
15.		Panasonic GF2	113 mm	68 mm	33 mm	310 g	300	n	Nov 2010	549	ebay.com
16.		Panasonic GF3	108 mm	67 mm	32 mm	264 g	300	n	Jun 2011	549	ebay.com
17.		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 retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. The Pentax Q was launched at a markedly lower price (by 92 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. 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 more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Pentax Q features a 1/2.3-inch sensor and the Pentax 645Z a medium format sensor. The sensor area in the 645Z is 5032 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 5.6 and 0.79. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.

With 51.1MP, the 645Z offers a higher resolution than the Pentax Q (12MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 1.53μm for the Pentax Q) due to its larger sensor. Moreover, the 645Z is a much more recent model (by 2 years and 9 months) than the Pentax Q, and its sensor will have benefitted from technological advances during this time that further 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 Pentax Q are 20 x 15 inches or 50.8 x 38.1 cm for good quality, 16 x 12 inches or 40.6 x 30.5 cm for very good quality, and 13.3 x 10 inches or 33.9 x 25.4 cm for excellent quality prints.

The Pentax Q has a native sensitivity range from ISO 125 to ISO 6400. 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 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 consideration, the 645Z offers substantially better image quality than the Pentax Q (overall score 54 points higher). The advantage is based on 5.8 bits higher color depth, 3.6 EV in additional dynamic range, and 4.6 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 Q	1/2.3	12.0	4000	3000	1080/30p	20.2	11.1	189	47
2.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
3.		Canon 5DS	Full Frame	50.3	8688	5792	1080/30p	24.7	12.4	2381	87
4.		Canon 5DS R	Full Frame	50.3	8688	5792	1080/30p	24.6	12.4	2308	86
5.		Fujifilm X10	2/3	12.0	4000	3000	1080/30p	20.5	11.3	245	50
6.		Hasselblad X1D	Medium Format	51.3	8272	6200	1080/25p	26.2	14.8	4489	102
7.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
8.		Olympus E-620	Four Thirds	12.2	4032	3024	none	21.3	10.3	536	55
9.		Olympus E-P3	Four Thirds	12.2	4032	3024	1080/60i	20.8	10.1	536	51
10.		Olympus E-PL1	Four Thirds	12.2	4032	3024	720/30p	21.5	10.1	487	54
11.		Olympus E-PL2	Four Thirds	12.2	4032	3024	720/30p	21.4	10.2	573	55
12.		Olympus E-PL3	Four Thirds	12.2	4032	3024	1080/60i	20.9	10.3	499	52
13.		Olympus XZ-2	1/1.7	11.8	3968	2976	1080/30p	20.4	11.3	216	49
14.		Panasonic G2	Four Thirds	12.0	4000	3000	720/30p	21.2	10.3	493	53
15.		Panasonic GF2	Four Thirds	12.0	4000	3000	1080/60i	21.2	10.3	506	54
16.		Panasonic GF3	Four Thirds	12.0	4000	3000	1080/60i	20.6	10.1	459	50
17.		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 faster frame rate than the Pentax Q. It can shoot movie footage at 1080/60i, while the Pentax Q is limited to 1080/30p.

Feature comparison

Apart from 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 Pentax Q relies on live view and the rear LCD for framing. That said, the Pentax Q can be equipped with an optional viewfinder – the O-VF1. The table below summarizes some of the other core capabilities of the Pentax Q and Pentax 645Z 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 Q	optional	n	3.0 / 460	fixed	n	1/2000s	1.5/s	Y	Y
2.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
3.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
4.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
5.		Fujifilm X10	optical	n	2.8 / 460	fixed	n	1/4000s	10.0/s	Y	Y
6.		Hasselblad X1D	2360	n	3.0 / 920	fixed	Y	1/2000s	2.3/s	n	n
7.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
8.		Olympus E-620	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
9.		Olympus E-P3	optional	n	3.0 / 614	fixed	Y	1/4000s	3.0/s	Y	Y
10.		Olympus E-PL1	optional	n	2.7 / 230	fixed	n	1/2000s	3.0/s	Y	Y
11.		Olympus E-PL2	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	Y
12.		Olympus E-PL3	optional	n	3.0 / 460	tilting	n	1/4000s	5.5/s	n	Y
13.		Olympus XZ-2	optional	n	3.0 / 920	tilting	Y	1/2000s	5.0/s	Y	Y
14.		Panasonic G2	1440	n	3.0 / 460	swivel	Y	1/4000s	2.6/s	Y	n
15.		Panasonic GF2	optional	n	3.0 / 460	fixed	Y	1/4000s	2.6/s	Y	n
16.		Panasonic GF3	none	n	3.0 / 460	fixed	Y	1/4000s	3.2/s	Y	n
17.		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.

One difference between the cameras concerns the presence of an on-board flash. The Pentax Q has one, while the 645Z does not. While the built-in flash of the Pentax Q is not very powerful, it can at times be useful as a fill-in light.

The Pentax Q 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 Pentax Q and the 645Z write their files to SDXC cards. The 645Z features dual card slots, which can be very useful in case a memory card fails. In contrast, the Pentax Q only has one slot. The 645Z supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the Pentax Q 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 Q 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 Q	Y	mono / mono	-	-	mini	2.0	-	-	-
2.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-
3.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
4.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
5.		Fujifilm X10	Y	stereo / mono	-	-	mini	2.0	-	-	-
6.		Hasselblad X1D	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
7.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
8.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
9.		Olympus E-P3	Y	stereo / -	-	-	mini	2.0	-	-	-
10.		Olympus E-PL1	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Olympus E-PL2	Y	stereo / -	-	-	mini	2.0	-	-	-
12.		Olympus E-PL3	Y	stereo / -	-	-	mini	2.0	-	-	-
13.		Olympus XZ-2	Y	stereo / mono	-	-	mini	2.0	-	-	-
14.		Panasonic G2	Y	stereo / mono	-	-	mini	2.0	-	-	-
15.		Panasonic GF2	Y	stereo / mono	-	-	mini	2.0	-	-	-
16.		Panasonic GF3	-	stereo / mono	-	-	mini	2.0	-	-	-
17.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-

It is notable that the 645Z has a microphone port, which can help to improve the quality of audio recordings by attaching an external microphone. The Pentax Q does not feature such a mic input.

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

Both the Pentax Q and the 645Z have been discontinued, but can regularly be found used on ebay. The Pentax Q was replaced by the Pentax Q10, while the 645Z does not have a direct successor. Further information on the features and operation of the Pentax Q and 645Z can be found, respectively, in the Pentax Q Manual (free pdf) or the online Pentax 645Z Manual.

Review summary

So how do things add up? Is there a clear favorite between the Pentax Q and the Pentax 645Z? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer the Pentax Q:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• More compact: Is smaller (98x57mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 1370g or 88 percent) and hence easier to carry around.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (92 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in June 2011).

Advantages of the Pentax 645Z:

• More detail: Has more megapixels (51.1 vs 12MP), which boosts linear resolution by 106%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (54 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (5.8 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (3.6 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (4.6 stops ISO advantage).
• Better video: Provides higher movie framerates (1080/60i versus 1080/30p).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• 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 460k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Faster shutter: Has higher mechanical shutter speed (1/4000s vs 1/2000s) to freeze action.
• Faster burst: Shoots at higher frequency (3 vs 1.5 flaps/sec) to capture the decisive moment.
• Longer lasting: Gets more shots (650 versus 230) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• 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: Reflects 2 years and 9 months of technical progress since the Pentax Q launch.

If the count of individual advantages (bullet points above) is taken as a guide, the 645Z is the clear winner of the contest (22 : 8 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 wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro 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 Q and the Pentax 645Z place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best DSLR 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 partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the Pentax Q or the 645Z. 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 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 (USD)	Street Price
1.		Pentax Q	3/5	..	..	..	4/5	3.5/5	Jun 2011	649	ebay.com
2.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	ebay.com
3.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	3,699	ebay.com
4.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	3,699	ebay.com
5.		Fujifilm X10	..	..	..	76/100	4/5	4.5/5	Sep 2011	599	ebay.com
6.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	8,995	ebay.com
7.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	7,450	ebay.com
8.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	699	ebay.com
9.		Olympus E-P3	..	83/100	..	74/100	4.5/5	4.5/5	Jun 2011	799	ebay.com
10.		Olympus E-PL1	..	86/100	..	69/100	4/5	4.5/5	Feb 2010	599	ebay.com
11.		Olympus E-PL2	3/5	83/100	..	71/100	4.5/5	4.5/5	Jan 2011	599	ebay.com
12.		Olympus E-PL3	3/5	+ +	..	72/100	4.5/5	4/5	Jun 2011	599	ebay.com
13.		Olympus XZ-2	4/5	+	..	..	4.5/5	4.5/5	Sep 2012	599	ebay.com
14.		Panasonic G2	..	..	..	72/100	4/5	4.5/5	Mar 2010	599	ebay.com
15.		Panasonic GF2	3/5	82/100	..	70/100	4.5/5	4.5/5	Nov 2010	549	ebay.com
16.		Panasonic GF3	3/5	82/100	..	71/100	4.5/5	4/5	Jun 2011	549	ebay.com
17.		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 ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Thus, a score needs to be put into the context of the launch date and the launch price 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.

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Other camera comparisons

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