Canon G12 vs Pentax 645D

The Canon PowerShot G12 and the Pentax 645D are two digital cameras that were announced, respectively, in September 2010 and March 2010. The G12 is a fixed lens compact, while the 645D is a DSLR. The cameras are based on a 1/1.7-inch (G12) and a medium format (645D) sensor. The Canon has a resolution of 10 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 G12		Pentax 645D
Fixed lens compact camera		Digital single lens reflex
28-140mm f/2.8-4.5		Pentax 645 mount lenses
10 MP – 1/1.7" sensor		39.5 MP – Medium Format sensor
720/24p Video		no Video
ISO 80-3,200 (80 - 12,800)		ISO 100-1,600
Optical viewfinder		Optical viewfinder
2.8" LCD – 461k dots		3.0" LCD – 921k dots
Swivel screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
1.1 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
370 shots per battery charge		800 shots per battery charge
112 x 76 x 48 mm, 401 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 G12 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 physical size and weight of the Canon G12 and the Pentax 645D are illustrated 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 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 (114 percent) than the Canon G12. It is noteworthy in this context that the 645D is splash and dust-proof, while the G12 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the G12 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 G12 gets 370 shots out of its Canon NB-7L 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 (USD)	Street Price
1.		Canon G12	112 mm	76 mm	48 mm	401 g	370	n	Sep 2010	499	ebay.com
2.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
3.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
4.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
5.		Canon G15	107 mm	76 mm	40 mm	352 g	350	n	Sep 2012	499	ebay.com
6.		Canon G16	109 mm	76 mm	40 mm	356 g	360	n	Aug 2013	549	ebay.com
7.		Canon SX50	123 mm	87 mm	106 mm	595 g	315	n	Sep 2012	429	ebay.com
8.		Fujifilm X10	117 mm	70 mm	57 mm	350 g	270	n	Sep 2011	599	ebay.com
9.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
10.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
11.		Nikon P7800	119 mm	78 mm	50 mm	399 g	350	n	Sep 2013	549	ebay.com
12.		Olympus E-450	130 mm	91 mm	53 mm	440 g	500	n	Mar 2009	499	ebay.com
13.		Panasonic FZ150	124 mm	82 mm	92 mm	528 g	410	n	Aug 2011	499	ebay.com
14.		Panasonic G2	124 mm	84 mm	74 mm	428 g	360	n	Mar 2010	599	ebay.com
15.		Panasonic G10	124 mm	84 mm	74 mm	388 g	380	n	Mar 2010	499	ebay.com
16.		Panasonic LX5	110 mm	65 mm	43 mm	271 g	400	n	Jul 2010	499	ebay.com
17.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The G12 was launched at a lower price than the 645D, 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 sensor inside a digital camera is one of the key determinants 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. 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 Canon G12 features a 1/1.7-inch sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 3277 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 4.6 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 G12 (10MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 2.07μm for the G12) due to its larger sensor. However, the G12 is a somewhat more recent model (by 6 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 G12 are 18.2 x 13.7 inches or 46.3 x 34.7 cm for good quality, 14.6 x 10.9 inches or 37.1 x 27.8 cm for very good quality, and 12.2 x 9.1 inches or 30.9 x 23.2 cm for excellent quality prints.

The Canon PowerShot G12 has a native sensitivity range from ISO 80 to ISO 3200, which can be extended to ISO 80-12800. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).

Technology-wise, both cameras are equipped with CCD (Charged Coupled Device) 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 assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. Of the two cameras under consideration, the 645D offers substantially better image quality than the G12 (overall score 35 points higher). The advantage is based on 4.2 bits higher color depth, 1.4 EV in additional dynamic range, and 3 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 G12	1/1.7	10.0	3648	2736	720/24p	20.4	11.2	161	47
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 G15	1/1.7	12.0	4000	3000	1080/24p	19.9	11.5	165	46
6.		Canon G16	1/1.7	12.0	4000	3000	1080/60p	21.0	11.7	230	54
7.		Canon SX50	1/2.3	12.0	4000	3000	1080/24p	20.3	11.2	179	47
8.		Fujifilm X10	2/3	12.0	4000	3000	1080/30p	20.5	11.3	245	50
9.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
10.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
11.		Nikon P7800	1/1.7	12.0	4000	3000	1080/30p	21.2	11.7	200	54
12.		Olympus E-450	Four Thirds	10.0	3648	2736	none	21.5	10.5	512	56
13.		Panasonic FZ150	1/2.3	12.0	4000	3000	1080/60p	19.4	10.9	132	40
14.		Panasonic G2	Four Thirds	12.0	4000	3000	720/30p	21.2	10.3	493	53
15.		Panasonic G10	Four Thirds	12.0	4000	3000	720/30p	21.2	10.1	411	52
16.		Panasonic LX5	1/1.7	10.0	3648	2736	720/60p	19.6	10.8	132	41
17.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101

Many modern cameras cannot only take still pictures, but also record videos. The G12 indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the G12 can use is 720/24p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The G12 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 adjacent table lists some of the other core features of the Canon G12 and Pentax 645D 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 G12	optical	n	2.8 / 461	swivel	n	1/4000s	1.1/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 G15	optical	n	3.0 / 922	fixed	n	1/4000s	2.1/s	Y	Y
6.		Canon G16	optical	n	3.0 / 922	fixed	n	1/4000s	2.2/s	Y	Y
7.		Canon SX50	202	n	3.0 / 461	swivel	n	1/2000s	2.2/s	Y	Y
8.		Fujifilm X10	optical	n	2.8 / 460	fixed	n	1/4000s	10.0/s	Y	Y
9.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
10.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
11.		Nikon P7800	921	n	3.0 / 921	swivel	n	1/4000s	8.0/s	Y	Y
12.		Olympus E-450	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
13.		Panasonic FZ150	202	n	3.0 / 460	swivel	n	1/2000s	12.0/s	Y	Y
14.		Panasonic G2	1440	n	3.0 / 460	swivel	Y	1/4000s	2.6/s	Y	n
15.		Panasonic G10	202	n	3.0 / 460	fixed	n	1/4000s	2.6/s	Y	n
16.		Panasonic LX5	optional	n	3.0 / 460	fixed	n	1/4000s	2.5/s	Y	Y
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 G12 has one, while the 645D does not. While the built-in flash of the G12 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 G12 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 G12 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 G12 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 G12	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 G15	Y	stereo / mono	-	-	mini	2.0	-	-	-
6.		Canon G16	Y	stereo / mono	-	-	mini	2.0	Y	-	-
7.		Canon SX50	Y	stereo / mono	-	-	mini	2.0	-	-	-
8.		Fujifilm X10	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
10.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Nikon P7800	Y	stereo / mono	Y	-	mini	2.0	-	-	-
12.		Olympus E-450	Y	- / -	-	-	-	2.0	-	-	-
13.		Panasonic FZ150	Y	stereo / -	-	-	mini	2.0	-	-	-
14.		Panasonic G2	Y	stereo / mono	-	-	mini	2.0	-	-	-
15.		Panasonic G10	Y	mono / -	-	-	mini	2.0	-	-	-
16.		Panasonic LX5	Y	mono / mono	-	-	mini	2.0	-	-	-
17.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

Studio photographers will appreciate that the Pentax 645D (unlike the G12) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the G12 and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the G12 was followed by the Canon G15. Further information on the features and operation of the G12 and 645D can be found, respectively, in the Canon G12 Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So what is the bottom line? Is the Canon G12 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 G12:

• 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 720/24p movies.
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• Ready to shoot: Comes with a built-in lens, while the 645D requires a separate lens.
• More compact: Is smaller (112x76mm 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 6 months after the 645D).

Arguments in favor of the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 10MP), which boosts linear resolution by 99%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (35 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (4.2 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1.4 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (3 stops ISO advantage).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.0" vs 2.8") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 461k dots).
• 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 370) 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 individual advantages (bullet points above) is taken as a guide, the 645D is the clear winner of the contest (16 : 10 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 Canon G12 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 specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it says little about, for example, the shooting experience and imaging performance of the G12 and the 645D in practical situations. 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 (USD)	Street Price
1.		Canon G12	4/5	+	..	73/100	4.5/5	4.5/5	Sep 2010	499	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
3.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
4.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
5.		Canon G15	4/5	+	..	76/100	4.5/5	4.5/5	Sep 2012	499	ebay.com
6.		Canon G16	4/5	+	..	..	4.5/5	4.5/5	Aug 2013	549	ebay.com
7.		Canon SX50	3/5	+ +	..	72/100	4.5/5	4.5/5	Sep 2012	429	ebay.com
8.		Fujifilm X10	..	..	..	76/100	4/5	4.5/5	Sep 2011	599	ebay.com
9.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
10.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
11.		Nikon P7800	3/5	..	..	..	4/5	4.5/5	Sep 2013	549	ebay.com
12.		Olympus E-450	..	..	..	..	4/5	4/5	Mar 2009	499	ebay.com
13.		Panasonic FZ150	3/5	+ +	..	76/100	4/5	4.5/5	Aug 2011	499	ebay.com
14.		Panasonic G2	..	..	..	72/100	4/5	4.5/5	Mar 2010	599	ebay.com
15.		Panasonic G10	3/5	..	..	70/100	4/5	4/5	Mar 2010	499	ebay.com
16.		Panasonic LX5	4/5	+	..	73/100	4.5/5	4.5/5	Jul 2010	499	ebay.com
17.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The assessments were made in relation to similar cameras of the same technological generation. 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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