Canon XTi vs Pentax K-3

The Canon EOS Rebel XTi (called Canon 400D in some regions) and the Pentax K-3 are two digital cameras that were announced, respectively, in August 2006 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 10.1 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 XTi		Pentax K-3
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Pentax K mount lenses
10.1 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
2.5" LCD – 230k dots		3.2" LCD – 1037k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
3 shutter flaps per second		8.3 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
370 shots per battery charge		560 shots per battery charge
127 x 84 x 65 mm, 556 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 Rebel XTi 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 XTi and the Pentax K-3. 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.

The K-3 can be obtained in two different colors (black, silver), while the XTi 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 K-3 is notably larger (23 percent) than the Canon XTi. Moreover, the K-3 is substantially heavier (44 percent) than the XTi. It is noteworthy in this context that the K-3 is splash and dust-proof, while the XTi 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 XTi gets 370 shots out of its NB-2LH battery, while the K-3 can take 560 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 XTi	127 mm	84 mm	65 mm	556 g	370	n	Aug 2006	799	ebay.com
2.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
3.		Canon T6i	132 mm	101 mm	78 mm	555 g	440	n	Feb 2015	749	ebay.com
4.		Canon T4i	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	849	ebay.com
5.		Canon T3	130 mm	100 mm	78 mm	495 g	700	n	Feb 2011	449	ebay.com
6.		Canon T2i	129 mm	98 mm	62 mm	530 g	440	n	Feb 2010	699	ebay.com
7.		Canon T1i	129 mm	98 mm	62 mm	520 g	400	n	Mar 2009	799	ebay.com
8.		Canon XS	126 mm	98 mm	65 mm	502 g	500	n	Jun 2008	449	ebay.com
9.		Canon XSi	129 mm	98 mm	62 mm	524 g	500	n	Jan 2008	799	ebay.com
10.		Canon 40D	146 mm	108 mm	74 mm	822 g	750	n	Aug 2007	1,299	ebay.com
11.		Canon XT	127 mm	94 mm	64 mm	540 g	400	n	Feb 2005	899	ebay.com
12.		Canon Rebel	142 mm	99 mm	72 mm	649 g	400	n	Aug 2003	899	ebay.com
13.		Nikon D7100	136 mm	107 mm	76 mm	765 g	950	Y	Feb 2013	1,199	ebay.com
14.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
15.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
16.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	1,099	ebay.com
17.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	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 XTi was launched at a markedly lower price (by 38 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 associated with larger, more expensive camera bodies 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 12 percent bigger. As a result of these sensor size differences, the cameras have format factors, respectively, of 1.6 (XTi) 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 XTi (10.1MP), but the K-3 has smaller individual pixels (pixel pitch of 3.90μm versus 5.71μm for the XTi). Yet, the K-3 is a much more recent model (by 7 years and 1 month) than the XTi, 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 XTi are 19.4 x 13 inches or 49.4 x 32.9 cm for good quality, 15.6 x 10.4 inches or 39.5 x 26.3 cm for very good quality, and 13 x 8.6 inches or 32.9 x 21.9 cm for excellent quality prints.

The Canon EOS Rebel XTi 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.

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 K-3 offers substantially better image quality than the XTi (overall score 18 points higher). The advantage is based on 1.6 bits higher color depth, 2.4 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 XTi	APS-C	10.1	3888	2592	none	22.1	11.0	664	62
2.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
3.		Canon T6i	APS-C	24.0	6000	4000	1080/30p	22.7	12.0	919	71
4.		Canon T4i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
5.		Canon T3	APS-C	12.2	4272	2848	720/30p	21.9	11.0	755	62
6.		Canon T2i	APS-C	17.9	5184	3456	1080/30p	22.1	11.5	784	66
7.		Canon T1i	APS-C	15.1	4752	3168	1080/20p	21.7	11.5	663	63
8.		Canon XS	APS-C	10.1	3888	2592	none	22.0	10.9	719	62
9.		Canon XSi	APS-C	12.2	4272	2848	none	21.9	10.8	692	61
10.		Canon 40D	APS-C	10.1	3888	2592	none	22.1	11.3	703	64
11.		Canon XT	APS-C	8.0	3456	2304	none	21.8	10.8	637	60
12.		Canon Rebel	APS-C	6.3	3072	2048	none	21.0	10.8	544	55
13.		Nikon D7100	APS-C	24.0	6000	4000	1080/60p	24.2	13.7	1256	83
14.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
15.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
16.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
17.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
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 K-3 indeed provides for movie recording, while the XTi 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 XTi 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 XTi (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 0.49x), 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 XTi, 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 XTi	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
2.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
3.		Canon T6i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
4.		Canon T4i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
5.		Canon T3	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
6.		Canon T2i	optical	n	3.0 / 1040	fixed	n	1/4000s	3.7/s	Y	n
7.		Canon T1i	optical	n	3.0 / 920	fixed	n	1/4000s	3.4/s	Y	n
8.		Canon XS	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
9.		Canon XSi	optical	n	3.0 / 230	fixed	n	1/4000s	3.5/s	Y	n
10.		Canon 40D	optical	Y	3.0 / 230	fixed	n	1/8000s	6.5/s	Y	n
11.		Canon XT	optical	n	1.8 / 115	fixed	n	1/4000s	3.0/s	Y	n
12.		Canon Rebel	optical	n	1.8 / 118	fixed	n	1/4000s	2.5/s	Y	n
13.		Nikon D7100	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
14.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
15.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
16.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
17.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
Notes: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the K-3 and the XTi is in-body image stabilization (IBIS). The K-3 reduces the risk of handshake-induced blur with all attached lenses, while the XTi 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 XTi 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 XTi 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 XTi 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 XTi	Y	- / -	-	-	-	2.0	-	-	-
2.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
3.		Canon T6i	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
4.		Canon T4i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
5.		Canon T3	Y	stereo / mono	-	-	mini	2.0	-	-	-
6.		Canon T2i	Y	stereo / -	Y	-	mini	2.0	-	-	-
7.		Canon T1i	Y	mono / mono	-	-	mini	2.0	-	-	-
8.		Canon XS	Y	- / -	-	-	-	2.0	-	-	-
9.		Canon XSi	Y	- / -	-	-	mini	2.0	-	-	-
10.		Canon 40D	Y	- / -	-	-	-	2.0	-	-	-
11.		Canon XT	Y	- / -	-	-	-	2.0	-	-	-
12.		Canon Rebel	Y	- / -	-	-	-	1.1	-	-	-
13.		Nikon D7100	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
14.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
15.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
16.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
17.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-

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

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

Review summary

So how do things add up? Is the Canon XTi better than the Pentax K-3 or vice versa? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Canon EOS Rebel XTi:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• More compact: Is smaller (127x84mm vs 131x100mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 244g or 30 percent) and hence easier to carry around.
• More affordable: Was introduced into a lower priced category (38 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2006).

Arguments in favor of the Pentax K-3:

• More detail: Has more megapixels (24.1 vs 10.1MP), which boosts linear resolution by 55%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (18 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (1.6 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.4 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (0.9 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 0.49x).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.2" vs 2.5") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (1037k vs 230k 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 3 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 370) 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 2.0).
• 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 7 years and 1 month of technical progress since the XTi launch.

If the count of relative strengths (bullet points above) is taken as a measure, the K-3 is the clear winner of the contest (22 : 5 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 XTi 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 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 XTi or the K-3. 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 XTi	..	+ +	..	+ +	o	4/5	Aug 2006	799	ebay.com
2.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
3.		Canon T6i	5/5	..	..	75/100	4.5/5	4.5/5	Feb 2015	749	ebay.com
4.		Canon T4i	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	849	ebay.com
5.		Canon T3	..	80/100	..	69/100	4/5	4.5/5	Feb 2011	449	ebay.com
6.		Canon T2i	..	+ +	..	77/100	4/5	4.5/5	Feb 2010	699	ebay.com
7.		Canon T1i	..	+ +	..	74/100	4.5/5	4.5/5	Mar 2009	799	ebay.com
8.		Canon XS	..	82/100	..	+ +	3.5/5	4.5/5	Jun 2008	449	ebay.com
9.		Canon XSi	..	+ +	..	+ +	4/5	4.5/5	Jan 2008	799	ebay.com
10.		Canon 40D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2007	1,299	ebay.com
11.		Canon XT	..	80/100	..	+ +	o	..	Feb 2005	899	ebay.com
12.		Canon Rebel	..	..	..	+ +	..	..	Aug 2003	899	ebay.com
13.		Nikon D7100	5/5	+ +	..	85/100	4.5/5	4.5/5	Feb 2013	1,199	ebay.com
14.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
15.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
16.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	1,099	ebay.com
17.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
Notes: (+ +) 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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