Canon 300D vs Pentax 645D

The Canon EOS 300D (called Canon Rebel in some regions) and the Pentax 645D are two digital cameras that were officially introduced, respectively, in August 2003 and March 2010. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (300D) and a medium format (645D) sensor. The Canon has a resolution of 6.3 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 300D		Pentax 645D
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Pentax 645 mount lenses
6.3 MP – APS-C sensor		39.5 MP – Medium Format sensor
no Video		no Video
ISO 100-1,600		ISO 100-1,600
Optical viewfinder		Optical viewfinder
1.8" LCD – 118k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
2.5 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
400 shots per battery charge		800 shots per battery charge
142 x 99 x 72 mm, 649 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 300D 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 300D 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 views from the front, the top, and the rear side 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 (30 percent) than the Canon 300D. Moreover, the 645D is substantially heavier (128 percent) than the 300D. It is noteworthy in this context that the 645D is splash and dust-proof, while the 300D 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 300D gets 400 shots out of its BP-511 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 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 300D	142 mm	99 mm	72 mm	649 g	400	n	Aug 2003	899	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 G1 X Mark II	116 mm	74 mm	66 mm	553 g	240	n	Feb 2014	799	ebay.com
5.		Canon 700D	133 mm	100 mm	79 mm	580 g	440	n	Mar 2013	649	ebay.com
6.		Canon 650D	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	849	ebay.com
7.		Canon G1 X	117 mm	81 mm	65 mm	534 g	250	n	Jan 2012	799	ebay.com
8.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
9.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
10.		Canon 400D	127 mm	84 mm	65 mm	556 g	370	n	Aug 2006	799	ebay.com
11.		Canon 350D	127 mm	94 mm	64 mm	540 g	400	n	Feb 2005	899	ebay.com
12.		Canon 20D	144 mm	106 mm	72 mm	770 g	700	n	Aug 2004	1,499	ebay.com
13.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	1,999	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.		Nikon D70	140 mm	111 mm	78 mm	679 g	400	n	Jan 2004	999	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 obviously take relative prices into account. 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 300D was launched at a markedly lower price (by 91 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 generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have 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 tend to be more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Canon 300D features an APS-C sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 323 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 300D 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 300D (6.3MP), but the 645D has smaller individual pixels (pixel pitch of 6.06μm versus 7.38μm for the 300D). Yet, the 645D is a much more recent model (by 6 years and 6 months) than the 300D, 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 300D are 15.4 x 10.2 inches or 39 x 26 cm for good quality, 12.3 x 8.2 inches or 31.2 x 20.8 cm for very good quality, and 10.2 x 6.8 inches or 26 x 17.3 cm for excellent quality prints.

The Canon EOS 300D has a native sensitivity range from ISO 100 to ISO 1600. The Pentax 645D offers exactly the same ISO settings.

In terms of underlying technology, the 300D 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 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 300D (overall score 27 points higher). The advantage is based on 3.6 bits higher color depth, 1.8 EV in additional dynamic range, and 1.2 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 300D	APS-C	6.3	3072	2048	none	21.0	10.8	544	55
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 G1 X Mark II	1.5-inch	13.0	4160	3120	1080/30p	21.5	10.8	581	58
5.		Canon 700D	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	681	61
6.		Canon 650D	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
7.		Canon G1 X	1.5-inch	14.2	4352	3264	1080/24p	21.7	10.8	644	60
8.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
9.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
10.		Canon 400D	APS-C	10.1	3888	2592	none	22.1	11.0	664	62
11.		Canon 350D	APS-C	8.0	3456	2304	none	21.8	10.8	637	60
12.		Canon 20D	APS-C	8.2	3504	2336	none	21.9	11.0	721	62
13.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
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.		Nikon D70	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
17.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The 300D 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 300D (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 0.55x), 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 300D, 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 300D	optical	n	1.8 / 118	fixed	n	1/4000s	2.5/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 G1 X Mark II	optional	n	3.0 / 1040	tilting	Y	1/4000s	5.2/s	Y	Y
5.		Canon 700D	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
6.		Canon 650D	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
7.		Canon G1 X	optical	n	3.0 / 922	swivel	n	1/4000s	1.9/s	Y	Y
8.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
9.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
10.		Canon 400D	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
11.		Canon 350D	optical	n	1.8 / 115	fixed	n	1/4000s	3.0/s	Y	n
12.		Canon 20D	optical	Y	1.8 / 118	fixed	n	1/8000s	5.0/s	Y	n
13.		Canon 10D	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	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.		Nikon D70	optical	n	1.8 / 130	fixed	n	1/8000s	3.0/s	Y	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 300D has one, while the 645D does not. While the built-in flash of the 300D 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.

The 300D writes its imaging data to Compact Flash cards, while the 645D uses SDXC cards. The 645D features dual card slots, which can be very useful in case a memory card fails. In contrast, the 300D 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 300D 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 300D	Y	- / -	-	-	-	1.1	-	-	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 77D	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
4.		Canon G1 X Mark II	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
5.		Canon 700D	Y	stereo / mono	Y	-	mini	2.0	-	-	-
6.		Canon 650D	Y	stereo / mono	Y	-	mini	2.0	-	-	-
7.		Canon G1 X	Y	stereo / mono	-	-	mini	2.0	-	-	-
8.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
9.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
10.		Canon 400D	Y	- / -	-	-	-	2.0	-	-	-
11.		Canon 350D	Y	- / -	-	-	-	2.0	-	-	-
12.		Canon 20D	Y	- / -	-	-	-	1.1	-	-	-
13.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
14.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
15.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
16.		Nikon D70	Y	- / -	-	-	-	1.0	-	-	-
17.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

Studio photographers will appreciate that the Pentax 645D (unlike the 300D) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 300D and the 645D have been discontinued, but can regularly be found used on ebay. The 300D was replaced by the Canon 350D, while the 645D was followed by the Pentax 645Z. Further information on the features and operation of the 300D and 645D can be found, respectively, in the Canon 300D Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So what is the bottom line? Is the Canon 300D better than the Pentax 645D or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer the Canon EOS 300D:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Faster burst: Shoots at higher frequency (2.5 vs 1.1 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (142x99mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 831g or 56 percent) and hence easier to carry around.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (91 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2003).

Arguments in favor of the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 6.3MP), which boosts linear resolution by 146%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (27 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (3.6 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 (1.2 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 0.55x).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.0" vs 1.8") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 118k dots).
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Gets more shots (800 versus 400) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Faster data transfer: Supports a more advanced USB protocol (2.0 vs 1.1).
• 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 modern: Reflects 6 years and 6 months of technical progress since the 300D launch.

If the count of relative strengths (bullet points above) is taken as a measure, the 645D is the clear winner of the contest (18 : 7 points). However, the relevance of individual strengths will vary across photographers, so that you might want to apply your own weighing scheme to the summary points when reflecting and deciding 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 300D 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 says little about, for example, the shooting experience and imaging performance of the 300D 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 expert reviews 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 300D	..	..	..	+ +	..	..	Aug 2003	899	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 G1 X Mark II	3/5	+	..	77/100	4/5	4.5/5	Feb 2014	799	ebay.com
5.		Canon 700D	..	..	..	76/100	4.5/5	4.5/5	Mar 2013	649	ebay.com
6.		Canon 650D	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	849	ebay.com
7.		Canon G1 X	5/5	+	..	76/100	4/5	4.5/5	Jan 2012	799	ebay.com
8.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
9.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
10.		Canon 400D	..	+ +	..	+ +	o	4/5	Aug 2006	799	ebay.com
11.		Canon 350D	..	80/100	..	+ +	o	..	Feb 2005	899	ebay.com
12.		Canon 20D	..	..	..	+ +	..	..	Aug 2004	1,499	ebay.com
13.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	1,999	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.		Nikon D70	..	..	..	+ +	..	..	Jan 2004	999	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. A score, therefore, has to be seen in close connection to the price and market introduction time 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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