Canon Rebel vs Pentax K-3

The Canon EOS Digital Rebel (called Canon 300D in some regions) and the Pentax K-3 are two digital cameras that were officially introduced, respectively, in August 2003 and October 2013. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Canon has a resolution of 6.3 megapixels, whereas the Pentax provides 24.1 MP.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Canon Rebel		Pentax K-3
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Pentax K mount lenses
6.3 MP – APS-C sensor		24.1 MP – APS-C sensor
no Video		1080/60i Video
ISO 100-1,600		ISO 100-51,200
Optical viewfinder		Optical viewfinder
1.8" LCD – 118k dots		3.2" LCD – 1037k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
2.5 shutter flaps per second		8.3 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
400 shots per battery charge		560 shots per battery charge
142 x 99 x 72 mm, 649 g		131 x 100 x 77 mm, 800 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS Digital Rebel and the Pentax K-3? 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 Rebel and the Pentax K-3. 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.

The K-3 can be obtained in two different colors (black, silver), while the Rebel is only available in silver.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-3 is notably smaller (7 percent) than the Canon Rebel. However, the K-3 is markedly heavier (23 percent) than the Rebel. It is noteworthy in this context that the K-3 is splash and dust-proof, while the Rebel 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 Rebel gets 400 shots out of its Canon BP-511 battery, while the K-3 can take 560 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. 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	Street Price
1.		Canon Rebel	142 mm	99 mm	72 mm	649 g	400	n	Aug 2003	EUR 1 095	ebay.com
2.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	EUR 1 299	ebay.com
3.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	EUR 1 999	ebay.com
4.		Canon 20D	144 mm	106 mm	72 mm	770 g	700	n	Aug 2004	EUR 1 599	ebay.com
5.		Canon 70D	139 mm	104 mm	79 mm	755 g	920	Y	Jul 2013	EUR 1 099	ebay.com
6.		Canon T1i	129 mm	98 mm	62 mm	520 g	400	n	Mar 2009	EUR 699	ebay.com
7.		Canon T3i	133 mm	100 mm	80 mm	570 g	440	n	Feb 2011	EUR 549	ebay.com
8.		Canon T4i	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	EUR 799	ebay.com
9.		Canon T6s	132 mm	101 mm	78 mm	565 g	440	n	Feb 2015	EUR 749	ebay.com
10.		Canon T7i	131 mm	100 mm	76 mm	532 g	600	n	Feb 2017	EUR 849	ebay.com
11.		Canon XT	127 mm	94 mm	64 mm	540 g	400	n	Feb 2005	EUR 899	ebay.com
12.		Canon XTi	127 mm	84 mm	65 mm	556 g	370	n	Aug 2006	EUR 799	ebay.com
13.		Nikon D70	140 mm	111 mm	78 mm	679 g	400	n	Jan 2004	EUR 999	ebay.com
14.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	EUR 999	ebay.com
15.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	EUR 999	ebay.com
16.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	EUR 999	ebay.com
17.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	EUR 1 299	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
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Any camera decision will obviously take relative prices into account. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The Rebel was launched at a markedly lower price (by 31 percent) than the K-3, 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 more expensive and lead to bigger and heavier cameras and lenses.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the K-3 is 7 percent bigger. As a result of these sensor size differences, the cameras have format factors, respectively, of 1.6 (Rebel) and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 24.1MP, the K-3 offers a higher resolution than the Rebel (6.3MP), but the K-3 has smaller individual pixels (pixel pitch of 3.90μm versus 7.38μm for the Rebel). Yet, the K-3 is a much more recent model (by 10 years and 1 month) than the Rebel, 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 K-3 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax K-3 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-3 for good quality output (200 dots per inch) amounts to 30.1 x 20 inches or 76.4 x 50.8 cm, for very good quality (250 dpi) 24.1 x 16 inches or 61.1 x 40.6 cm, and for excellent quality (300 dpi) 20.1 x 13.3 inches or 50.9 x 33.9 cm. The corresponding values for the Canon Rebel 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 Digital Rebel has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Pentax K-3 are ISO 100 to ISO 51200 (no boost).

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) 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 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 K-3 offers substantially better image quality than the Rebel (overall score 25 points higher). The advantage is based on 2.7 bits higher color depth, 2.6 EV in additional dynamic range, and 1.2 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 Rebel	APS-C	6.3	3072	2048	none	21.0	10.8	544	55
2.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
3.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
4.		Canon 20D	APS-C	8.2	3504	2336	none	21.9	11.0	721	62
5.		Canon 70D	APS-C	20.0	5472	3648	1080/30p	22.5	11.6	926	68
6.		Canon T1i	APS-C	15.1	4752	3168	1080/20p	21.7	11.5	663	63
7.		Canon T3i	APS-C	17.9	5184	3456	1080/30p	22.1	11.5	793	65
8.		Canon T4i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
9.		Canon T6s	APS-C	24.0	6000	4000	1080/30p	22.6	12.0	915	70
10.		Canon T7i	APS-C	24.0	6000	4000	1080/60p	23.7	13.1	1586	80
11.		Canon XT	APS-C	8.0	3456	2304	none	21.8	10.8	637	60
12.		Canon XTi	APS-C	10.1	3888	2592	none	22.1	11.0	664	62
13.		Nikon D70	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
14.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
15.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
16.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
17.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
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 K-3 indeed provides for movie recording, while the Rebel does not. The highest resolution format that the K-3 can use is 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The Rebel and the K-3 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 K-3 offers a wider field of view (100%) than the one in the Rebel (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the K-3 has a higher magnification (0.63x 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 Rebel, the Pentax K-3, 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 Rebel	optical	n	1.8 / 118	fixed	n	1/4000s	2.5/s	Y	n
2.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
3.		Canon 10D	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
4.		Canon 20D	optical	Y	1.8 / 118	fixed	n	1/8000s	5.0/s	Y	n
5.		Canon 70D	optical	Y	3.0 / 1040	swivel	Y	1/8000s	7.0/s	Y	n
6.		Canon T1i	optical	n	3.0 / 920	fixed	n	1/4000s	3.4/s	Y	n
7.		Canon T3i	optical	n	3.0 / 1040	swivel	n	1/4000s	3.7/s	Y	n
8.		Canon T4i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
9.		Canon T6s	optical	Y	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
10.		Canon T7i	optical	n	3.0 / 1040	swivel	Y	1/4000s	6.0/s	Y	n
11.		Canon XT	optical	n	1.8 / 115	fixed	n	1/4000s	3.0/s	Y	n
12.		Canon XTi	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
13.		Nikon D70	optical	n	1.8 / 130	fixed	n	1/8000s	3.0/s	Y	n
14.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
15.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
16.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
17.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the K-3 and the Rebel is in-body image stabilization (IBIS). The K-3 reduces the risk of handshake-induced blur with all attached lenses, while the Rebel offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The Pentax K-3 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 Rebel writes its imaging data to Compact Flash cards, while the K-3 uses SDXC cards. The K-3 features dual card slots, which can be very useful in case a memory card fails. In contrast, the Rebel 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 Digital Rebel and Pentax K-3 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 Rebel	Y	- / -	-	-	-	1.1	-	-	-
2.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
3.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
4.		Canon 20D	Y	- / -	-	-	-	1.1	-	-	-
5.		Canon 70D	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
6.		Canon T1i	Y	mono / mono	-	-	mini	2.0	-	-	-
7.		Canon T3i	Y	mono / mono	Y	-	mini	2.0	-	-	-
8.		Canon T4i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
9.		Canon T6s	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
10.		Canon T7i	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
11.		Canon XT	Y	- / -	-	-	-	2.0	-	-	-
12.		Canon XTi	Y	- / -	-	-	-	2.0	-	-	-
13.		Nikon D70	Y	- / -	-	-	-	1.0	-	-	-
14.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
17.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-

Studio photographers will appreciate that the Pentax K-3 (unlike the Rebel) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the Rebel and the K-3 have been discontinued, but can regularly be found used on ebay. The Rebel was replaced by the Canon XT, while the K-3 was followed by the Pentax K-3 II. Further information on the features and operation of the Rebel and K-3 can be found, respectively, in the Canon Rebel Manual (free pdf) or the online Pentax K-3 Manual.

Review summary

So how do things add up? Which of the two cameras – the Canon Rebel or the Pentax K-3 – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Canon EOS Digital Rebel:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Less heavy: Is lighter (by 151g or 19 percent) and hence easier to carry around.
• More affordable: Was introduced into a lower priced category (31 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2003).

Arguments in favor of the Pentax K-3:

• More detail: Has more megapixels (24.1 vs 6.3MP), which boosts linear resolution by 96%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (25 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 (2.6 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (1.2 stops ISO advantage).
• Broader imaging potential: Can capture not only stills but also 1080/60i video.
• More complete view: Has a viewfinder with a larger field of view (100% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.63x vs 0.55x).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.2" vs 1.8") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (1037k vs 118k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (8.3 vs 2.5 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Gets more shots (560 versus 400) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Faster data transfer: Supports a more advanced USB protocol (3.0 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 10 years and 1 month of technical progress since the Rebel launch.

If the count of individual advantages (bullet points above) is taken as a guide, the K-3 is the clear winner of the contest (22 : 4 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 wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports 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 Rebel and the Pentax K-3 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 technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the Rebel and the K-3 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 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	Street Price
1.		Canon Rebel	..	..	..	+ +	..	..	Aug 2003	EUR 1 095	ebay.com
2.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	EUR 1 299	ebay.com
3.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	EUR 1 999	ebay.com
4.		Canon 20D	..	..	..	+ +	..	..	Aug 2004	EUR 1 599	ebay.com
5.		Canon 70D	5/5	+ +	..	83/100	4.5/5	5/5	Jul 2013	EUR 1 099	ebay.com
6.		Canon T1i	..	+ +	..	74/100	4.5/5	4.5/5	Mar 2009	EUR 699	ebay.com
7.		Canon T3i	3/5	o	..	77/100	4.5/5	4.5/5	Feb 2011	EUR 549	ebay.com
8.		Canon T4i	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	EUR 799	ebay.com
9.		Canon T6s	5/5	+	..	77/100	4.5/5	4.5/5	Feb 2015	EUR 749	ebay.com
10.		Canon T7i	4.5/5	..	3.5/5	80/100	4.5/5	4/5	Feb 2017	EUR 849	ebay.com
11.		Canon XT	..	80/100	..	+ +	o	..	Feb 2005	EUR 899	ebay.com
12.		Canon XTi	..	+ +	..	+ +	o	4/5	Aug 2006	EUR 799	ebay.com
13.		Nikon D70	..	..	..	+ +	..	..	Jan 2004	EUR 999	ebay.com
14.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	EUR 999	ebay.com
15.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	EUR 999	ebay.com
16.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	EUR 999	ebay.com
17.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	EUR 1 299	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. 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. 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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