Canon T100 vs Pentax 645D

The Canon EOS Rebel T100 (called Canon 4000D in some regions) and the Pentax 645D are two digital cameras that were announced, respectively, in February 2018 and March 2010. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (T100) 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 T100		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 100-6,400 (100 - 12,800)		ISO 100-1,600
Optical viewfinder		Optical viewfinder
2.7" LCD – 230k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
3 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
500 shots per battery charge		800 shots per battery charge
129 x 102 x 77 mm, 436 g		156 x 117 x 119 mm, 1480 g

Check T100 price at
amazon.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 T100 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 T100 and the Pentax 645D. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth measures 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 (39 percent) than the Canon T100. Moreover, the 645D is substantially heavier (239 percent) than the T100. It is noteworthy in this context that the 645D is splash and dust-proof, while the T100 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 T100 gets 500 shots out of its Canon LP-E10 battery, while the 645D can take 800 images on a single charge of its Pentax 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 T100	129 mm	102 mm	77 mm	436 g	500	n	Feb 2018	399	amazon.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 SL1	117 mm	91 mm	69 mm	407 g	380	n	Mar 2013	549	ebay.com
6.		Canon SL2	122 mm	93 mm	70 mm	453 g	650	n	Jun 2017	549	ebay.com
7.		Canon T1i	129 mm	98 mm	62 mm	520 g	400	n	Mar 2009	799	ebay.com
8.		Canon T2i	129 mm	98 mm	62 mm	530 g	440	n	Feb 2010	699	ebay.com
9.		Canon T3	130 mm	100 mm	78 mm	495 g	700	n	Feb 2011	449	ebay.com
10.		Canon T5	130 mm	100 mm	78 mm	480 g	500	n	Feb 2014	449	ebay.com
11.		Canon T5i	133 mm	100 mm	79 mm	580 g	440	n	Mar 2013	649	ebay.com
12.		Canon T6	129 mm	101 mm	78 mm	485 g	500	n	Mar 2016	449	ebay.com
13.		Canon T7	129 mm	101 mm	78 mm	475 g	500	n	Feb 2018	449	amazon.com
14.		Canon XS	126 mm	98 mm	65 mm	502 g	500	n	Jun 2008	449	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	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 T100 was launched at a markedly lower price (by 96 percent) than the 645D, which puts it into a different market segment. 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. 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. 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Canon T100 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 T100 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 T100 (17.9MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 4.31μm for the T100) due to its larger sensor. However, the T100 is a much more recent model (by 7 years and 11 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 T100 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 Canon EOS Rebel T100 has a native sensitivity range from ISO 100 to ISO 6400, which can be extended to ISO 100-12800. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).

In terms of underlying technology, the T100 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 T100 (overall score 19 points higher). The advantage is based on 2.7 bits higher color depth, 1.2 EV in additional dynamic range, and 0.9 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 T100	APS-C	17.9	5184	3456	1080/30p	21.9	11.4	695	63
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 SL1	APS-C	17.9	5184	3456	1080/30p	21.8	11.3	843	63
6.		Canon SL2	APS-C	24.0	6000	4000	1080/60p	23.6	13.4	1041	79
7.		Canon T1i	APS-C	15.1	4752	3168	1080/20p	21.7	11.5	663	63
8.		Canon T2i	APS-C	17.9	5184	3456	1080/30p	22.1	11.5	784	66
9.		Canon T3	APS-C	12.2	4272	2848	720/30p	21.9	11.0	755	62
10.		Canon T5	APS-C	17.9	5184	3456	1080/30p	21.9	11.3	724	63
11.		Canon T5i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	681	61
12.		Canon T6	APS-C	17.9	5184	3456	1080/30p	22.0	11.7	781	66
13.		Canon T7	APS-C	24.0	6000	4000	1080/30p	23.8	13.3	1684	81
14.		Canon XS	APS-C	10.1	3888	2592	none	22.0	10.9	719	62
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 also of capturing video footage. The T100 indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the T100 can use is 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The T100 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 T100 (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 0.50x), 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 T100, 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 T100	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
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 SL1	optical	n	3.0 / 1040	fixed	Y	1/4000s	4.9/s	Y	n
6.		Canon SL2	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
7.		Canon T1i	optical	n	3.0 / 920	fixed	n	1/4000s	3.4/s	Y	n
8.		Canon T2i	optical	n	3.0 / 1040	fixed	n	1/4000s	3.7/s	Y	n
9.		Canon T3	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
10.		Canon T5	optical	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	n
11.		Canon T5i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
12.		Canon T6	optical	n	3.0 / 920	fixed	n	1/4000s	3.0/s	Y	n
13.		Canon T7	optical	n	3.0 / 920	fixed	n	1/4000s	3.0/s	Y	n
14.		Canon XS	optical	n	2.5 / 230	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
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 T100 has one, while the 645D does not. While the built-in flash of the T100 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 T100 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 T100 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 EOS Rebel T100 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 T100	Y	mono / mono	-	-	mini	2.0	Y	Y	-
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 SL1	Y	mono / mono	Y	-	mini	2.0	-	-	-
6.		Canon SL2	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
7.		Canon T1i	Y	mono / mono	-	-	mini	2.0	-	-	-
8.		Canon T2i	Y	stereo / -	Y	-	mini	2.0	-	-	-
9.		Canon T3	Y	stereo / mono	-	-	mini	2.0	-	-	-
10.		Canon T5	Y	mono / mono	-	-	mini	2.0	-	-	-
11.		Canon T5i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
12.		Canon T6	Y	mono / mono	-	-	mini	2.0	Y	Y	-
13.		Canon T7	Y	mono / mono	-	-	mini	2.0	Y	Y	-
14.		Canon XS	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 T100 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 T100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

The T100 is a recent model that features in the current product line-up of Canon. In contrast, the 645D has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the 645D was succeeded by the Pentax 645Z. Further information on the features and operation of the T100 and 645D can be found, respectively, in the Canon T100 Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So how do things add up? Is the Canon T100 better than the Pentax 645D or vice versa? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Canon EOS Rebel T100:

• 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.
• Faster burst: Shoots at higher frequency (3 vs 1.1 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (129x102mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 1044g or 71 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.
• More affordable: Was introduced into a lower priced category (96 percent cheaper at launch).
• More modern: Reflects 7 years and 11 months of technical progress since the 645D launch.

Arguments in favor of 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 (2.7 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1.2 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (0.9 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 0.50x).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.0" vs 2.7") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 230k dots).
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Gets more shots (800 versus 500) 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 645D is the clear winner of the contest (17 : 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 T100 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 remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the T100 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 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 T100	..	o	3/5	..	3.5/5	3.5/5	Feb 2018	399	amazon.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 SL1	4/5	+	..	78/100	4/5	4/5	Mar 2013	549	ebay.com
6.		Canon SL2	4/5	+ +	4/5	78/100	4.5/5	4.5/5	Jun 2017	549	ebay.com
7.		Canon T1i	..	+ +	..	74/100	4.5/5	4.5/5	Mar 2009	799	ebay.com
8.		Canon T2i	..	+ +	..	77/100	4/5	4.5/5	Feb 2010	699	ebay.com
9.		Canon T3	..	80/100	..	69/100	4/5	4.5/5	Feb 2011	449	ebay.com
10.		Canon T5	3/5	+	..	..	4/5	4.5/5	Feb 2014	449	ebay.com
11.		Canon T5i	..	..	..	76/100	4.5/5	4.5/5	Mar 2013	649	ebay.com
12.		Canon T6	4/5	o	4/5	73/100	4/5	4/5	Mar 2016	449	ebay.com
13.		Canon T7	..	o	3.5/5	..	3.5/5	3.5/5	Feb 2018	449	amazon.com
14.		Canon XS	..	82/100	..	+ +	3.5/5	4.5/5	Jun 2008	449	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	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated 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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. 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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