Canon T6i vs Pentax 645D

The Canon EOS Rebel T6i (called Canon 750D in some regions) and the Pentax 645D are two digital cameras that were officially introduced, respectively, in February 2015 and March 2010. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (T6i) and a medium format (645D) sensor. The Canon has a resolution of 24 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 T6i		Pentax 645D
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Pentax 645 mount lenses
24 MP – APS-C sensor		39.5 MP – Medium Format sensor
1080/30p Video		no Video
ISO 100-12,800 (100 - 25,600)		ISO 100-1,600
Optical viewfinder		Optical viewfinder
3.0" LCD – 1040k dots		3.0" LCD – 921k dots
Swivel touchscreen		Fixed screen (not touch-sensitive)
5 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
440 shots per battery charge		800 shots per battery charge
132 x 101 x 78 mm, 555 g		156 x 117 x 119 mm, 1480 g

Check T6i offers at
ebay.com
Check 645D offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS Rebel T6i 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 T6i 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 perspectives from the front, the top, and the back are available. 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 notably larger (37 percent) than the Canon T6i. Moreover, the 645D is substantially heavier (167 percent) than the T6i. It is noteworthy in this context that the 645D is splash and dust-proof, while the T6i 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.

Concerning battery life, the T6i gets 440 shots out of its LP-E17 battery, while the 645D can take 800 images on a single charge of its D-LI90 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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.		Canon T6i	132 mm	101 mm	78 mm	555 g	440	n	Feb 2015	749	ebay.com
2.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
3.		Canon 77D	131 mm	100 mm	76 mm	540 g	600	n	Feb 2017	899	ebay.com
4.		Canon T7i	131 mm	100 mm	76 mm	532 g	600	n	Feb 2017	749	ebay.com
5.		Canon T6s	132 mm	101 mm	78 mm	565 g	440	n	Feb 2015	649	ebay.com
6.		Canon T5	130 mm	100 mm	78 mm	480 g	500	n	Feb 2014	449	ebay.com
7.		Canon T5i	133 mm	100 mm	79 mm	580 g	440	n	Mar 2013	649	ebay.com
8.		Canon T4i	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	849	ebay.com
9.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
10.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
11.		Canon T1i	129 mm	98 mm	62 mm	520 g	400	n	Mar 2009	799	ebay.com
12.		Canon XSi	129 mm	98 mm	62 mm	524 g	500	n	Jan 2008	799	ebay.com
13.		Canon XTi	127 mm	84 mm	65 mm	556 g	370	n	Aug 2006	799	ebay.com
14.		Canon XT	127 mm	94 mm	64 mm	540 g	400	n	Feb 2005	899	ebay.com
15.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
16.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
17.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	8,499	amazon.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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The T6i was launched at a markedly lower price (by 93 percent) than the 645D, which puts it into a different market segment. 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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. 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Canon T6i features an APS-C sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 337 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.6 and 0.79. The sensor in the T6i has a native 3:2 aspect ratio, while the one in the 645D offers a 4:3 aspect.

With 39.5MP, the 645D offers a higher resolution than the T6i (24MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 3.72μm for the T6i) due to its larger sensor. However, the T6i is a much more recent model (by 4 years and 10 months) than the 645D, and its sensor will 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 T6i 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 T6i has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Canon EOS Rebel T6i has a native sensitivity range from ISO 100 to ISO 12800, which can be extended to ISO 100-25600. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).

In terms of underlying technology, the T6i 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.

For many cameras, data on sensor performance has been reported by DXO Mark. 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 T6i (overall score 11 points higher). The advantage is based on 1.9 bits higher color depth, 0.6 EV in additional dynamic range, and 0.5 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.		Canon T6i	APS-C	24.0	6000	4000	1080/30p	22.7	12.0	919	71
2.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
3.		Canon 77D	APS-C	24.0	6000	4000	1080/60p	23.6	13.3	971	78
4.		Canon T7i	APS-C	24.0	6000	4000	1080/60p	23.7	13.1	1586	80
5.		Canon T6s	APS-C	24.0	6000	4000	1080/30p	22.6	12.0	915	70
6.		Canon T5	APS-C	17.9	5184	3456	1080/30p	21.9	11.3	724	63
7.		Canon T5i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	681	61
8.		Canon T4i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
9.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
10.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
11.		Canon T1i	APS-C	15.1	4752	3168	1080/20p	21.7	11.5	663	63
12.		Canon XSi	APS-C	12.2	4272	2848	none	21.9	10.8	692	61
13.		Canon XTi	APS-C	10.1	3888	2592	none	22.1	11.0	664	62
14.		Canon XT	APS-C	8.0	3456	2304	none	21.8	10.8	637	60
15.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
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 can also record movies. The T6i indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the T6i can use is 1080/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The T6i 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 viewfinder in the 645D offers a wider field of view (98%) than the one in the T6i (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the 645D has a higher magnification (0.78x vs 0.51x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The following table reports on some other key feature differences and similarities of the Canon T6i, the Pentax 645D, and comparable 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 T6i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
2.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
3.		Canon 77D	optical	Y	3.0 / 1040	swivel	Y	1/4000s	6.0/s	Y	n
4.		Canon T7i	optical	n	3.0 / 1040	swivel	Y	1/4000s	6.0/s	Y	n
5.		Canon T6s	optical	Y	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
6.		Canon T5	optical	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	n
7.		Canon T5i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
8.		Canon T4i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
9.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
10.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
11.		Canon T1i	optical	n	3.0 / 920	fixed	n	1/4000s	3.4/s	Y	n
12.		Canon XSi	optical	n	3.0 / 230	fixed	n	1/4000s	3.5/s	Y	n
13.		Canon XTi	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
14.		Canon XT	optical	n	1.8 / 115	fixed	n	1/4000s	3.0/s	Y	n
15.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
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
Notes: *) 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 T6i has one, while the 645D does not. While the built-in flash of the T6i 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 T6i 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 T6i only has one slot. The T6i supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the 645D 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 Canon EOS Rebel T6i 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 T6i	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 77D	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
4.		Canon T7i	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
5.		Canon T6s	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
6.		Canon T5	Y	mono / mono	-	-	mini	2.0	-	-	-
7.		Canon T5i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
8.		Canon T4i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
9.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
10.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
11.		Canon T1i	Y	mono / mono	-	-	mini	2.0	-	-	-
12.		Canon XSi	Y	- / -	-	-	mini	2.0	-	-	-
13.		Canon XTi	Y	- / -	-	-	-	2.0	-	-	-
14.		Canon XT	Y	- / -	-	-	-	2.0	-	-	-
15.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
16.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
17.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

It is notable that the T6i offers wifi support, while the 645D 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 645D (unlike the T6i) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the T6i and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the T6i was followed by the Canon T7i. Further information on the features and operation of the T6i and 645D can be found, respectively, in the Canon T6i Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So what is the bottom line? Is there a clear favorite between the Canon T6i and the Pentax 645D? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer the Canon EOS Rebel T6i:

• 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 1080/30p movies.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• More detailed LCD: Has a higher resolution rear screen (1040k vs 921k dots).
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• 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 (5 vs 1.1 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (132x101mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 925g or 62 percent) and hence easier to carry around.
• 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.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More affordable: Was introduced into a lower priced category (93 percent cheaper at launch).
• More modern: Reflects 4 years and 10 months of technical progress since the 645D launch.

Arguments in favor of the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 24MP), which boosts linear resolution by 26%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (11 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (1.9 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (0.6 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (0.5 stops ISO advantage).
• More complete view: Has a viewfinder with a larger field of view (98% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.51x).
• 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.
• Longer lasting: Gets more shots (800 versus 440) 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 around for much longer (launched in March 2010).

If the count of relative strengths (bullet points above) is taken as a measure, the T6i comes out slightly ahead of the 645D (16 : 15 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 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 T6i and the Pentax 645D place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing 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 T6i 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 where reviews by experts come in. 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 T6i	5/5	..	..	75/100	4.5/5	4.5/5	Feb 2015	749	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
3.		Canon 77D	4.5/5	..	4/5	82/100	4.5/5	4/5	Feb 2017	899	ebay.com
4.		Canon T7i	4.5/5	..	3.5/5	80/100	4.5/5	4/5	Feb 2017	749	ebay.com
5.		Canon T6s	5/5	+	..	77/100	4.5/5	4.5/5	Feb 2015	649	ebay.com
6.		Canon T5	3/5	+	..	..	4/5	4.5/5	Feb 2014	449	ebay.com
7.		Canon T5i	..	..	..	76/100	4.5/5	4.5/5	Mar 2013	649	ebay.com
8.		Canon T4i	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	849	ebay.com
9.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
10.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
11.		Canon T1i	..	+ +	..	74/100	4.5/5	4.5/5	Mar 2009	799	ebay.com
12.		Canon XSi	..	+ +	..	+ +	4/5	4.5/5	Jan 2008	799	ebay.com
13.		Canon XTi	..	+ +	..	+ +	o	4/5	Aug 2006	799	ebay.com
14.		Canon XT	..	80/100	..	+ +	o	..	Feb 2005	899	ebay.com
15.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
16.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
17.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	amazon.com
Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, 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 comparing ratings of very distinct cameras or ones that are far apart in terms of their release date 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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Other camera comparisons

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