Canon G7 X vs Pentax 645Z

The Canon PowerShot G7 X and the Pentax 645Z are two digital cameras that were revealed to the public, respectively, in September 2014 and April 2014. The G7X is a fixed lens compact, while the 645Z is a DSLR. The cameras are based on an one-inch (G7X) and a medium format (645Z) sensor. The Canon has a resolution of 20 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 G7 X		Pentax 645Z
Fixed lens compact camera		Digital single lens reflex
24-100mm f/1.8-2.8		Pentax 645 mount lenses
20 MP – 1" sensor		51.1 MP – Medium Format sensor
1080/60p Video		1080/60i Video
ISO 125-12,800		ISO 100-204,800
No viewfinder, LCD framing		Optical viewfinder
3.0" LCD – 1040k dots		3.2" LCD – 1037k dots
Tilting touchscreen		Tilting screen (no touchscreen)
6.5 shutter flaps per second		3 shutter flaps per second
not weather sealed		Weathersealed body
210 shots per battery charge		650 shots per battery charge
103 x 60 x 40 mm, 304 g		156 x 117 x 123 mm, 1550 g

Check G7X offers at
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Check 645Z offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon PowerShot G7 X 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 Canon G7 X 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.

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 (195 percent) than the Canon G7 X. It is noteworthy in this context that the 645Z is splash and dust-proof, while the G7X does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the G7X 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 G7X gets 210 shots out of its Canon NB-13L battery, while the 645Z can take 650 images on a single charge of its Pentax D-LI90 power pack.

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 (USD)	Street Price
1.		Canon G7 X	103 mm	60 mm	40 mm	304 g	210	n	Sep 2014	699	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.		Canon G5 X	112 mm	76 mm	44 mm	353 g	210	n	Oct 2015	799	ebay.com
6.		Canon G7 X Mark II	106 mm	61 mm	42 mm	319 g	265	n	Feb 2016	699	ebay.com
7.		Canon G7 X Mark III	105 mm	61 mm	41 mm	304 g	235	n	Jul 2019	749	amazon.com
8.		Canon G9 X	98 mm	58 mm	31 mm	209 g	220	n	Oct 2015	529	ebay.com
9.		Canon M3	111 mm	68 mm	44 mm	366 g	250	n	Feb 2015	679	ebay.com
10.		Canon M10	108 mm	67 mm	35 mm	301 g	255	n	Oct 2015	499	ebay.com
11.		Canon T6i	132 mm	101 mm	78 mm	555 g	440	n	Feb 2015	749	ebay.com
12.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	8,995	ebay.com
13.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	7,450	ebay.com
14.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
15.		Sony RX100 II	102 mm	58 mm	38 mm	281 g	350	n	Jun 2013	749	ebay.com
16.		Sony RX100 III	102 mm	58 mm	41 mm	290 g	320	n	May 2014	799	ebay.com
17.		Sony RX100 IV	102 mm	58 mm	41 mm	298 g	280	n	Jun 2015	999	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 naturally be influenced heavily by the price. 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 G7X was launched at a lower price than the 645Z, despite having a lens built in. 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 imaging sensor is a crucial determinant of image quality. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixels 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 Canon G7 X features an one-inch sensor and the Pentax 645Z a medium format sensor. The sensor area in the 645Z is 1139 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.7 and 0.79. The sensor in the G7X 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 G7X (20MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 2.41μm for the G7X) due to its larger sensor. However, the G7X is a somewhat more recent model (by 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 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 G7 X are 27.4 x 18.2 inches or 69.5 x 46.3 cm for good quality, 21.9 x 14.6 inches or 55.6 x 37.1 cm for very good quality, and 18.2 x 12.2 inches or 46.3 x 30.9 cm for excellent quality prints.

The Canon PowerShot G7 X has a native sensitivity range from ISO 125 to ISO 12800. The corresponding ISO settings for the Pentax 645Z are ISO 100 to ISO 204800 (no boost).

In terms of underlying technology, the G7X is build around a BSI-CMOS 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.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. This service is based on lab testing and assigns an overall score to each camera sensor, as well as ratings for dynamic range ("DXO Landscape"), color depth ("DXO Portrait"), and low-light sensitivity ("DXO Sports"). Of the two cameras under consideration, the 645Z offers substantially better image quality than the G7X (overall score 30 points higher). The advantage is based on 3 bits higher color depth, 2 EV in additional dynamic range, and 3 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.		Canon G7 X	1-inch	20.0	5472	3648	1080/60p	23.0	12.7	556	71
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.		Canon G5 X	1-inch	20.0	5472	3648	1080/60p	21.4	12.3	471	62
6.		Canon G7 X Mark II	1-inch	20.0	5472	3648	1080/60p	21.8	11.9	260	62
7.		Canon G7 X Mark III	1-inch	20.0	5472	3648	4K/30p	22.2	12.4	583	65
8.		Canon G9 X	1-inch	20.0	5472	3648	1080/60p	21.5	12.3	495	63
9.		Canon M3	APS-C	24.0	6000	4000	1080/30p	22.8	11.8	1169	72
10.		Canon M10	APS-C	17.9	5184	3456	1080/30p	22.2	11.4	753	65
11.		Canon T6i	APS-C	24.0	6000	4000	1080/30p	22.7	12.0	919	71
12.		Hasselblad X1D	Medium Format	51.3	8272	6200	1080/25p	26.2	14.8	4489	102
13.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
14.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
15.		Sony RX100 II	1-inch	20.0	5472	3648	1080/60p	22.5	12.4	483	67
16.		Sony RX100 III	1-inch	20.0	5472	3648	1080/60p	22.4	12.3	495	67
17.		Sony RX100 IV	1-inch	20.0	5472	3648	4K/30p	22.8	12.6	591	70
Note: DXO values in italics represent estimates based on sensor size and age.

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 G7X provides a higher frame rate than the 645Z. It can shoot video footage at 1080/60p, while the Pentax is limited to 1080/60i.

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 G7X relies on live view and the rear LCD for framing. The adjacent table lists some of the other core features of the Canon G7 X 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.		Canon G7 X	none	n	3.0 / 1040	tilting	Y	1/2000s	6.5/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.		Canon G5 X	2360	n	3.0 / 1040	swivel	Y	1/2000s	5.9/s	Y	Y
6.		Canon G7 X Mark II	none	n	3.0 / 1040	tilting	Y	1/2000s	8.0/s	Y	Y
7.		Canon G7 X Mark III	none	n	3.0 / 1040	tilting	Y	1/2000s	30/s	Y	Y
8.		Canon G9 X	none	n	3.0 / 1040	fixed	Y	1/2000s	6.0/s	Y	Y
9.		Canon M3	optional	n	3.0 / 1040	tilting	Y	1/4000s	4.2/s	Y	n
10.		Canon M10	none	n	3.0 / 1040	tilting	Y	1/4000s	4.6/s	Y	n
11.		Canon T6i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
12.		Hasselblad X1D	2360	n	3.0 / 920	fixed	Y	1/2000s	2.3/s	n	n
13.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
14.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
15.		Sony RX100 II	optional	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
16.		Sony RX100 III	1440	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
17.		Sony RX100 IV	2359	n	3.0 / 1228	tilting	n	1/2000s	16.0/s	Y	Y
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 G7X has one, while the 645Z does not. While the built-in flash of the G7X is not very powerful, it can at times be useful as a fill-in light.

The Canon G7 X 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 G7X 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 G7X 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 Canon PowerShot G7 X 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 G7 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
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.		Canon G5 X	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
6.		Canon G7 X Mark II	-	stereo / mono	-	-	micro	2.0	Y	Y	-
7.		Canon G7 X Mark III	-	stereo / mono	Y	-	micro	3.1	Y	-	Y
8.		Canon G9 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
9.		Canon M3	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
10.		Canon M10	-	stereo / mono	-	-	mini	2.0	Y	Y	-
11.		Canon T6i	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
12.		Hasselblad X1D	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
13.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
14.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
15.		Sony RX100 II	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
16.		Sony RX100 III	-	stereo / mono	-	-	micro	2.0	Y	Y	-
17.		Sony RX100 IV	-	stereo / mono	-	-	micro	2.0	Y	Y	-

It is notable that the G7X offers wifi support, while the 645Z does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Studio photographers will appreciate that the Pentax 645Z (unlike the G7X) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the G7X and the 645Z have been discontinued, but can regularly be found used on ebay. The G7X was replaced by the Canon G7 X Mark II, while the 645Z does not have a direct successor. Further information on the features and operation of the G7X and 645Z can be found, respectively, in the Canon G7 X Manual (free pdf) or the online Pentax 645Z Manual.

Review summary

So what conclusions can be drawn? Is the Canon G7 X better than the Pentax 645Z or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Canon PowerShot G7 X:

• 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).
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster burst: Shoots at higher frequency (6.5 vs 3 flaps/sec) to capture the decisive moment.
• Ready to shoot: Comes with a built-in lens, while the 645Z requires a separate lens.
• More compact: Is smaller (103x60mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter even though it comes with a built-in lens (unlike the 645Z).
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• 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: Is somewhat more recent (announced 5 months after the 645Z).

Arguments in favor of the Pentax 645Z:

• More detail: Has more megapixels (51.1 vs 20MP), which boosts linear resolution by 57%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (30 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (3 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (3 stops ISO advantage).
• 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.
• Faster shutter: Has higher mechanical shutter speed (1/4000s vs 1/2000s) to freeze action.
• More flexible: Makes it possible to change lenses and thus to use specialty optics.
• Longer lasting: Gets more shots (650 versus 210) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• 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).

If the count of individual advantages (bullet points above) is taken as a guide, the 645Z is the clear winner of the contest (19 : 14 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 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 Canon G7 X and the Pentax 645Z place the cameras among the top in their class? Find out in the latest Best Travel-Zoom Camera and Best DSLR Camera listings 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 incomplete and does no justice, for example, to the way the G7X 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 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 (USD)	Street Price
1.		Canon G7 X	4/5	+ +	..	77/100	4.5/5	4.5/5	Sep 2014	699	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.		Canon G5 X	5/5	+ +	..	78/100	4.5/5	4.5/5	Oct 2015	799	ebay.com
6.		Canon G7 X Mark II	4.5/5	+ +	..	81/100	4.5/5	4.5/5	Feb 2016	699	ebay.com
7.		Canon G7 X Mark III	..	+ +	4/5	81/100	4/5	..	Jul 2019	749	amazon.com
8.		Canon G9 X	3.5/5	+ +	..	..	4.5/5	4.5/5	Oct 2015	529	ebay.com
9.		Canon M3	4/5	o	..	75/100	4.5/5	4/5	Feb 2015	679	ebay.com
10.		Canon M10	..	..	..	..	..	4/5	Oct 2015	499	ebay.com
11.		Canon T6i	5/5	..	..	75/100	4.5/5	4.5/5	Feb 2015	749	ebay.com
12.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	8,995	ebay.com
13.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	7,450	ebay.com
14.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
15.		Sony RX100 II	5/5	+ +	..	79/100	4.5/5	4.5/5	Jun 2013	749	ebay.com
16.		Sony RX100 III	5/5	+ +	..	82/100	4.5/5	5/5	May 2014	799	ebay.com
17.		Sony RX100 IV	4.5/5	+ +	..	85/100	4/5	4.5/5	Jun 2015	999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. 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. 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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