Canon 100D vs Pentax 645D

The Canon EOS 100D (called Canon SL1 in some regions) and the Pentax 645D are two digital cameras that were officially introduced, respectively, in March 2013 and March 2010. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (100D) and a medium format (645D) sensor. The Canon has a resolution of 17.9 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 100D		Pentax 645D
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Pentax 645 mount lenses
17.9 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
Fixed touchscreen		Fixed screen (not touch-sensitive)
4.9 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
380 shots per battery charge		800 shots per battery charge
117 x 91 x 69 mm, 407 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 EOS 100D 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

An illustration of the physical size and weight of the Canon 100D and the Pentax 645D is provided 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 measures are rounded to the nearest millimeter.

The 100D can be obtained in two different colors (black, white), while the 645D 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 645D is considerably larger (71 percent) than the Canon 100D. Moreover, the 645D is substantially heavier (264 percent) than the 100D. It is noteworthy in this context that the 645D is splash and dust-proof, while the 100D 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 100D gets 380 shots out of its Canon LP-E12 battery, while the 645D can take 800 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 100D	117 mm	91 mm	69 mm	407 g	380	n	Mar 2013	549	ebay.com
2.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
3.		Canon 4000D	129 mm	102 mm	77 mm	436 g	500	n	Feb 2018	399	amazon.com
4.		Canon 200D	122 mm	93 mm	70 mm	453 g	650	n	Jun 2017	549	ebay.com
5.		Canon 1300D	129 mm	101 mm	78 mm	485 g	500	n	Mar 2016	449	ebay.com
6.		Canon 1200D	130 mm	100 mm	78 mm	480 g	500	n	Feb 2014	449	ebay.com
7.		Canon 700D	133 mm	100 mm	79 mm	580 g	440	n	Mar 2013	649	ebay.com
8.		Canon G16	109 mm	76 mm	40 mm	356 g	360	n	Aug 2013	549	ebay.com
9.		Canon 650D	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	849	ebay.com
10.		Canon M	109 mm	66 mm	32 mm	298 g	230	n	Jul 2012	599	ebay.com
11.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
12.		Canon 600D	133 mm	100 mm	80 mm	570 g	440	n	Feb 2011	599	ebay.com
13.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
14.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
15.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
16.		Panasonic G6	122 mm	85 mm	71 mm	390 g	340	n	Apr 2013	599	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

Any camera decision will naturally be influenced heavily by the price. 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 100D was launched at a markedly lower price (by 95 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 size of the imaging sensor is a crucial determinant of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Canon 100D 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 100D 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 100D (17.9MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 4.31μm for the 100D) due to its larger sensor. However, the 100D is a much more recent model (by 3 years) 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 100D are 25.9 x 17.3 inches or 65.8 x 43.9 cm for good quality, 20.7 x 13.8 inches or 52.7 x 35.1 cm for very good quality, and 17.3 x 11.5 inches or 43.9 x 29.3 cm for excellent quality prints.

The 100D has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Canon EOS 100D 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 100D 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.

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 645D offers substantially better image quality than the 100D (overall score 19 points higher). The advantage is based on 2.8 bits higher color depth, 1.3 EV in additional dynamic range, and 0.6 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.		Canon 100D	APS-C	17.9	5184	3456	1080/30p	21.8	11.3	843	63
2.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
3.		Canon 4000D	APS-C	17.9	5184	3456	1080/30p	21.9	11.4	695	63
4.		Canon 200D	APS-C	24.0	6000	4000	1080/60p	23.6	13.4	1041	79
5.		Canon 1300D	APS-C	17.9	5184	3456	1080/30p	22.0	11.7	781	66
6.		Canon 1200D	APS-C	17.9	5184	3456	1080/30p	21.9	11.3	724	63
7.		Canon 700D	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	681	61
8.		Canon G16	1/1.7	12.0	4000	3000	1080/60p	21.0	11.7	230	54
9.		Canon 650D	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
10.		Canon M	APS-C	17.9	5184	3456	1080/30p	22.1	11.2	827	65
11.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
12.		Canon 600D	APS-C	17.9	5184	3456	1080/30p	22.1	11.5	793	65
13.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
14.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
15.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
16.		Panasonic G6	Four Thirds	15.9	4608	3456	1080/60p	21.3	11.5	639	61
17.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The 100D indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the 100D can use is 1080/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The 100D 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 100D (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 0.54x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Canon 100D 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 100D	optical	n	3.0 / 1040	fixed	Y	1/4000s	4.9/s	Y	n
2.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
3.		Canon 4000D	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
4.		Canon 200D	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
5.		Canon 1300D	optical	n	3.0 / 920	fixed	n	1/4000s	3.0/s	Y	n
6.		Canon 1200D	optical	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	n
7.		Canon 700D	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
8.		Canon G16	optical	n	3.0 / 922	fixed	n	1/4000s	2.2/s	Y	Y
9.		Canon 650D	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
10.		Canon M	none	n	3.0 / 1040	fixed	Y	1/4000s	4.3/s	n	n
11.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
12.		Canon 600D	optical	n	3.0 / 1040	swivel	n	1/4000s	3.7/s	Y	n
13.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
14.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
15.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
16.		Panasonic G6	1440	n	3.0 / 1036	swivel	Y	1/4000s	7.0/s	Y	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 100D has one, while the 645D does not. While the built-in flash of the 100D 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 100D 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 100D only has one slot. The 100D 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 100D 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 100D	Y	mono / mono	Y	-	mini	2.0	-	-	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 4000D	Y	mono / mono	-	-	mini	2.0	Y	Y	-
4.		Canon 200D	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
5.		Canon 1300D	Y	mono / mono	-	-	mini	2.0	Y	Y	-
6.		Canon 1200D	Y	mono / mono	-	-	mini	2.0	-	-	-
7.		Canon 700D	Y	stereo / mono	Y	-	mini	2.0	-	-	-
8.		Canon G16	Y	stereo / mono	-	-	mini	2.0	Y	-	-
9.		Canon 650D	Y	stereo / mono	Y	-	mini	2.0	-	-	-
10.		Canon M	Y	stereo / mono	Y	-	mini	2.0	-	-	-
11.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
12.		Canon 600D	Y	mono / mono	Y	-	mini	2.0	-	-	-
13.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
14.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
15.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
16.		Panasonic G6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
17.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

Studio photographers will appreciate that the Pentax 645D (unlike the 100D) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 100D and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the 100D was followed by the Canon 200D. Further information on the features and operation of the 100D and 645D can be found, respectively, in the Canon 100D Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So what conclusions can be drawn? Is the Canon 100D 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 EOS 100D:

• 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).
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• Faster burst: Shoots at higher frequency (4.9 vs 1.1 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (117x91mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 1073g or 72 percent) and hence easier to carry around.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More affordable: Was introduced into a lower priced category (95 percent cheaper at launch).
• More modern: Reflects 3 years of technical progress since the 645D launch.

Reasons to prefer the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 17.9MP), which boosts linear resolution by 46%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (19 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.8 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1.3 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (0.6 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 0.54x).
• 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 380) 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 individual advantages (bullet points above) is taken as a guide, the 645D emerges as the winner of the match-up (15 : 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 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 100D 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 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 100D and the 645D in practical situations. 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 table below provides a synthesis of the camera assessments of some of the best known photo-gear 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 100D	4/5	+	..	78/100	4/5	4/5	Mar 2013	549	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
3.		Canon 4000D	2.5/5	o	3/5	..	3.5/5	3.5/5	Feb 2018	399	amazon.com
4.		Canon 200D	4/5	+ +	4/5	78/100	4.5/5	4.5/5	Jun 2017	549	ebay.com
5.		Canon 1300D	4/5	o	4/5	73/100	4/5	4/5	Mar 2016	449	ebay.com
6.		Canon 1200D	3/5	+	..	..	4/5	4.5/5	Feb 2014	449	ebay.com
7.		Canon 700D	..	..	..	76/100	4.5/5	4.5/5	Mar 2013	649	ebay.com
8.		Canon G16	4/5	+	..	..	4.5/5	4.5/5	Aug 2013	549	ebay.com
9.		Canon 650D	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	849	ebay.com
10.		Canon M	3/5	+	..	..	4/5	4/5	Jul 2012	599	ebay.com
11.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
12.		Canon 600D	3/5	o	..	77/100	4.5/5	4.5/5	Feb 2011	599	ebay.com
13.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
14.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
15.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
16.		Panasonic G6	4/5	+ +	..	..	5/5	4.5/5	Apr 2013	599	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 ratings are only valid when referring to cameras in the same category and of the same age. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

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Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just use the search menu below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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