Canon G1 X vs Pentax 645D

The Canon PowerShot G1 X and the Pentax 645D are two digital cameras that were officially introduced, respectively, in January 2012 and March 2010. The G1X is a fixed lens compact, while the 645D is a DSLR. The cameras are based on an 1.5-inch (G1X) and a medium format (645D) sensor. The Canon has a resolution of 14.2 megapixels, whereas the Pentax provides 39.5 MP.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Canon G1 X		Pentax 645D
Fixed lens compact camera		Digital single lens reflex
28-112mm f/2.8-5.8		Pentax 645 mount lenses
14.2 MP – 1.5" sensor		39.5 MP – Medium Format sensor
1080/24p Video		no Video
ISO 100-12,800		ISO 100-1,600
Optical viewfinder		Optical viewfinder
3.0" LCD – 922k dots		3.0" LCD – 921k dots
Swivel screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
1.9 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
250 shots per battery charge		800 shots per battery charge
117 x 81 x 65 mm, 534 g		156 x 117 x 119 mm, 1480 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon PowerShot G1 X and the Pentax 645D? 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 G1 X and the Pentax 645D. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All size 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 645D is considerably larger (93 percent) than the Canon G1 X. It is noteworthy in this context that the 645D is splash and dust-proof, while the G1X does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the G1X has a lens built in, whereas the 645D 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 G1X gets 250 shots out of its Canon NB-10L battery, while the 645D can take 800 images on a single charge of its Pentax D-LI90 power pack.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price	Street Price
1.		Canon G1 X	117 mm	81 mm	65 mm	534 g	250	n	Jan 2012	US$ 799	ebay.com
2.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	US$ 9 995	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 G1 X Mark II	116 mm	74 mm	66 mm	553 g	240	n	Feb 2014	US$ 799	ebay.com
6.		Canon G16	109 mm	76 mm	40 mm	356 g	360	n	Aug 2013	US$ 549	ebay.com
7.		Canon S120	100 mm	59 mm	29 mm	217 g	230	n	Aug 2013	US$ 449	ebay.com
8.		Canon SX50	123 mm	87 mm	106 mm	595 g	315	n	Sep 2012	US$ 429	ebay.com
9.		Canon T1i	129 mm	98 mm	62 mm	520 g	400	n	Mar 2009	US$ 799	ebay.com
10.		Canon T3	130 mm	100 mm	78 mm	495 g	700	n	Feb 2011	US$ 449	ebay.com
11.		Canon T4i	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	US$ 849	ebay.com
12.		Canon XSi	129 mm	98 mm	62 mm	524 g	500	n	Jan 2008	US$ 799	ebay.com
13.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	US$ 21 949	ebay.com
14.		Leica V-LUX 3	124 mm	81 mm	95 mm	540 g	410	n	Dec 2011	US$ 949	ebay.com
15.		Leica V-LUX 4	125 mm	87 mm	110 mm	588 g	540	n	Sep 2012	US$ 949	ebay.com
16.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	US$ 5 199	ebay.com
17.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	US$ 8 499	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 G1X was launched at a lower price than the 645D, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

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 G1 X features an 1.5-inch sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 454 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.85 and 0.79. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.

With 39.5MP, the 645D offers a higher resolution than the G1X (14.2MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 4.30μm for the G1X) due to its larger sensor. However, the G1X is a somewhat more recent model (by 1 year and 10 months) than the 645D, 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 645D has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax 645D implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 645D for good quality output (200 dots per inch) amounts to 36.3 x 27.2 inches or 92.3 x 69.1 cm, for very good quality (250 dpi) 29.1 x 21.8 inches or 73.8 x 55.3 cm, and for excellent quality (300 dpi) 24.2 x 18.1 inches or 61.5 x 46.1 cm. The corresponding values for the Canon G1 X are 21.8 x 16.3 inches or 55.3 x 41.5 cm for good quality, 17.4 x 13.1 inches or 44.2 x 33.2 cm for very good quality, and 14.5 x 10.9 inches or 36.8 x 27.6 cm for excellent quality prints.

The Canon PowerShot G1 X has a native sensitivity range from ISO 100 to ISO 12800. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).

In terms of underlying technology, the G1X is build around a CMOS sensor, while the 645D uses a CCD 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 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 645D offers substantially better image quality than the G1X (overall score 22 points higher). The advantage is based on 2.9 bits higher color depth, 1.8 EV in additional dynamic range, and 1 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.		Canon G1 X	1.5-inch	14.2	4352	3264	1080/24p	21.7	10.8	644	60
2.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
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 G1 X Mark II	1.5-inch	13.0	4160	3120	1080/30p	21.5	10.8	581	58
6.		Canon G16	1/1.7	12.0	4000	3000	1080/60p	21.0	11.7	230	54
7.		Canon S120	1/1.7	12.0	4000	3000	1080/60p	21.3	11.9	246	56
8.		Canon SX50	1/2.3	12.0	4000	3000	1080/24p	20.3	11.2	179	47
9.		Canon T1i	APS-C	15.1	4752	3168	1080/20p	21.7	11.5	663	63
10.		Canon T3	APS-C	12.2	4272	2848	720/30p	21.9	11.0	755	62
11.		Canon T4i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
12.		Canon XSi	APS-C	12.2	4272	2848	none	21.9	10.8	692	61
13.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
14.		Leica V-LUX 3	1/2.3	12.0	4000	3000	1080/60p	19.7	11.0	430	42
15.		Leica V-LUX 4	1/2.3	12.0	4000	3000	1080/60p	19.8	11.1	501	43
16.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
17.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
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 also of capturing video footage. The G1X indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the G1X can use is 1080/24p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The G1X and the 645D 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 table below summarizes some of the other core capabilities of the Canon G1 X and Pentax 645D 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.		Canon G1 X	optical	n	3.0 / 922	swivel	n	1/4000s	1.9/s	Y	Y
2.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/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 G1 X Mark II	optional	n	3.0 / 1040	tilting	Y	1/4000s	5.2/s	Y	Y
6.		Canon G16	optical	n	3.0 / 922	fixed	n	1/4000s	2.2/s	Y	Y
7.		Canon S120	none	n	3.0 / 922	fixed	Y	1/2000s	12.1/s	Y	Y
8.		Canon SX50	202	n	3.0 / 461	swivel	n	1/2000s	2.2/s	Y	Y
9.		Canon T1i	optical	n	3.0 / 920	fixed	n	1/4000s	3.4/s	Y	n
10.		Canon T3	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
11.		Canon T4i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
12.		Canon XSi	optical	n	3.0 / 230	fixed	n	1/4000s	3.5/s	Y	n
13.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
14.		Leica V-LUX 3	202	n	3.0 / 460	swivel	n	1/2000s	12.0/s	Y	Y
15.		Leica V-LUX 4	1312	n	3.0 / 460	swivel	n	1/4000s	12.0/s	Y	Y
16.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
17.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/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 G1X has one, while the 645D does not. While the built-in flash of the G1X is not very powerful, it can at times be useful as a fill-in light.

The Pentax 645D 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.

Concerning the storage of imaging data, both the G1X and the 645D write their files to SDXC cards. The 645D features dual card slots, which can be very useful in case a memory card fails. In contrast, the G1X only has one slot.

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 G1 X and Pentax 645D 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 G1 X	Y	stereo / mono	-	-	mini	2.0	-	-	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
4.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
5.		Canon G1 X Mark II	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
6.		Canon G16	Y	stereo / mono	-	-	mini	2.0	Y	-	-
7.		Canon S120	-	stereo / mono	-	-	mini	2.0	Y	-	-
8.		Canon SX50	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Canon T1i	Y	mono / mono	-	-	mini	2.0	-	-	-
10.		Canon T3	Y	stereo / mono	-	-	mini	2.0	-	-	-
11.		Canon T4i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
12.		Canon XSi	Y	- / -	-	-	mini	2.0	-	-	-
13.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
14.		Leica V-LUX 3	Y	stereo / -	-	-	mini	2.0	-	-	-
15.		Leica V-LUX 4	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
17.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

Studio photographers will appreciate that the Pentax 645D (unlike the G1X) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the G1X and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the G1X was followed by the Canon G1X Mark II. Further information on the features and operation of the G1X and 645D can be found, respectively, in the Canon G1 X Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So how do things add up? Is the Canon G1 X better than the Pentax 645D or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Canon PowerShot G1 X:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Broader imaging potential: Can record not only still images but also 1080/24p movies.
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster burst: Shoots at higher frequency (1.9 vs 1.1 flaps/sec) to capture the decisive moment.
• Ready to shoot: Comes with a built-in lens, while the 645D requires a separate lens.
• More compact: Is smaller (117x81mm 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 645D).
• 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.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More modern: Is somewhat more recent (announced 1 year and 10 months after the 645D).

Reasons to prefer the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 14.2MP), which boosts linear resolution by 67%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (22 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.9 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1.8 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (1 stops ISO advantage).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More flexible: Makes it possible to change lenses and thus to use specialty optics.
• Longer lasting: Gets more shots (800 versus 250) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• 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 March 2010).

If the count of relative strengths (bullet points above) is taken as a measure, the 645D emerges as the winner of the match-up (14 : 12 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 Canon G1 X and the Pentax 645D 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 partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the G1X or the 645D. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.

Expert reviews

This is why hands-on reviews by experts are important. The adjacent summary-table relays the overall verdicts of several of the most popular 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.		Canon G1 X	5/5	+	..	76/100	4/5	4.5/5	Jan 2012	US$ 799	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	US$ 9 995	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 G1 X Mark II	3/5	+	..	77/100	4/5	4.5/5	Feb 2014	US$ 799	ebay.com
6.		Canon G16	4/5	+	..	..	4.5/5	4.5/5	Aug 2013	US$ 549	ebay.com
7.		Canon S120	..	+ +	..	..	4.5/5	4.5/5	Aug 2013	US$ 449	ebay.com
8.		Canon SX50	3/5	+ +	..	72/100	4.5/5	4.5/5	Sep 2012	US$ 429	ebay.com
9.		Canon T1i	..	+ +	..	74/100	4.5/5	4.5/5	Mar 2009	US$ 799	ebay.com
10.		Canon T3	..	80/100	..	69/100	4/5	4.5/5	Feb 2011	US$ 449	ebay.com
11.		Canon T4i	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	US$ 849	ebay.com
12.		Canon XSi	..	+ +	..	+ +	4/5	4.5/5	Jan 2008	US$ 799	ebay.com
13.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	US$ 21 949	ebay.com
14.		Leica V-LUX 3	..	..	..	..	..	..	Dec 2011	US$ 949	ebay.com
15.		Leica V-LUX 4	..	..	..	..	..	..	Sep 2012	US$ 949	ebay.com
16.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	US$ 5 199	ebay.com
17.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	US$ 8 499	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 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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