Canon 1Ds Mark III vs XSi

The Canon EOS-1Ds Mark III and the Canon EOS Rebel XSi (labelled Canon 450D in some countries) are two digital cameras that were revealed to the public, respectively, in August 2007 and January 2008. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a full frame (1Ds Mark III) and an APS-C (XSi) sensor. The 1Ds Mark III has a resolution of 21 megapixels, whereas the XSi provides 12.2 MP.

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

Headline Specifications

Canon 1Ds Mark III		Canon XSi
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Canon EF mount lenses
21 MP – Full Frame sensor		12.2 MP – APS-C sensor
no Video		no Video
ISO 100-1,600 (50 - 3,200)		ISO 100-1,600
Optical viewfinder		Optical viewfinder
3.0" LCD – 230k dots		3.0" LCD – 230k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
5 shutter flaps per second		3.5 shutter flaps per second
Weathersealed body		not weather sealed
1800 shots per battery charge		500 shots per battery charge
150 x 160 x 80 mm, 1385 g		129 x 98 x 62 mm, 524 g

Check 1Ds Mark III offers at
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Check XSi offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS-1Ds Mark III and the Canon EOS Rebel XSi? 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 1Ds Mark III and the Canon XSi 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 size dimensions 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 Canon XSi is considerably smaller (47 percent) than the Canon 1Ds Mark III. Moreover, the XSi is substantially lighter (62 percent) than the 1Ds Mark III. It is worth mentioning in this context that the 1Ds Mark III is splash and dust resistant, while the XSi 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. A larger imaging sensor (as in the 1Ds Mark III) will tend to go along with bigger and heavier lenses, while more compact options are available for the smaller-sensor camera (XSi). You can compare the optics available in the Canon EF Lens Catalog.

Concerning battery life, the 1Ds Mark III gets 1800 shots out of its Canon LP-E4 battery, while the XSi can take 500 images on a single charge of its Canon LP-E5 power pack. As can be seen in the images above, the 1Ds Mark III has a battery grip built in. This facilitates image-taking in portrait orientation and gives it additional battery power. In order to provide similar functionality for the XSi, Canon provides the BG-E5 vertical grip as an optional accessory (see here on ebay).

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 1Ds Mark III	150 mm	160 mm	80 mm	1385 g	1800	Y	Aug 2007	7,999	ebay.com
2.		Canon XSi	129 mm	98 mm	62 mm	524 g	500	n	Jan 2008	799	ebay.com
3.		Canon 1D Mark III	156 mm	157 mm	80 mm	1155 g	2200	Y	Feb 2007	4,499	ebay.com
4.		Canon 1Ds	156 mm	158 mm	80 mm	1265 g	600	Y	Sep 2002	8,999	ebay.com
5.		Canon 1Ds Mark II	156 mm	158 mm	80 mm	1215 g	1200	Y	Sep 2004	7,999	ebay.com
6.		Canon 1D C	158 mm	164 mm	83 mm	1545 g	1120	Y	Apr 2012	14,999	ebay.com
7.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
8.		Canon 1D X Mark II	158 mm	168 mm	83 mm	1530 g	1210	Y	Feb 2016	5,999	ebay.com
9.		Canon 1D X Mark III	158 mm	168 mm	83 mm	1440 g	2850	Y	Jan 2020	6,499	amazon.com
10.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
11.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
12.		Canon 40D	146 mm	108 mm	74 mm	822 g	750	n	Aug 2007	1,299	ebay.com
13.		Canon T1i	129 mm	98 mm	62 mm	520 g	400	n	Mar 2009	799	ebay.com
14.		Canon T3	130 mm	100 mm	78 mm	495 g	700	n	Feb 2011	449	ebay.com
15.		Canon T4i	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	849	ebay.com
16.		Canon XTi	127 mm	84 mm	65 mm	556 g	370	n	Aug 2006	799	ebay.com
17.		Nikon D3X	160 mm	157 mm	88 mm	1260 g	4400	Y	Dec 2008	7,999	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

The price is, of course, an important factor in any camera decision. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The XSi was launched at a markedly lower price (by 90 percent) than the 1Ds Mark III, 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. 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. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixels in a sensor of the same technological generation. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better 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.

Of the two cameras under consideration, the Canon 1Ds Mark III features a full frame sensor and the Canon XSi an APS-C sensor. The sensor area in the XSi is 62 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 1.6. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 21MP, the 1Ds Mark III offers a higher resolution than the XSi (12.2MP), but the 1Ds Mark III nevertheless has larger individual pixels (pixel pitch of 6.41μm versus 5.19μm for the XSi) due to its larger sensor. However, the XSi is a somewhat more recent model (by 5 months) than the 1Ds Mark III, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels.

The resolution advantage of the Canon 1Ds Mark III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 1Ds Mark III for good quality output (200 dots per inch) amounts to 28.1 x 18.7 inches or 71.3 x 47.5 cm, for very good quality (250 dpi) 22.5 x 15 inches or 57.1 x 38 cm, and for excellent quality (300 dpi) 18.7 x 12.5 inches or 47.5 x 31.7 cm. The corresponding values for the Canon XSi are 21.4 x 14.2 inches or 54.3 x 36.2 cm for good quality, 17.1 x 11.4 inches or 43.4 x 28.9 cm for very good quality, and 14.2 x 9.5 inches or 36.2 x 24.1 cm for excellent quality prints.

The Canon EOS-1Ds Mark III has a native sensitivity range from ISO 100 to ISO 1600, which can be extended to ISO 50-3200. The corresponding ISO settings for the Canon EOS Rebel XSi are ISO 100 to ISO 1600 (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 review, the 1Ds Mark III provides substantially higher image quality than the XSi, with an overall score that is 19 points higher. This advantage is based on 2.1 bits higher color depth, 1.2 EV in additional dynamic range, and 1.3 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 1Ds Mark III	Full Frame	21.0	5616	3744	none	24.0	12.0	1663	80
2.		Canon XSi	APS-C	12.2	4272	2848	none	21.9	10.8	692	61
3.		Canon 1D Mark III	APS-H	10.1	3888	2592	none	22.7	11.7	1078	71
4.		Canon 1Ds	Full Frame	11.0	4064	2704	none	21.8	11.0	954	63
5.		Canon 1Ds Mark II	Full Frame	16.6	4992	3328	none	23.3	11.3	1480	74
6.		Canon 1D C	Full Frame	17.9	5184	3456	4K/24p	24.3	13.0	2155	85
7.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
8.		Canon 1D X Mark II	Full Frame	20.0	5472	3648	4K/60p	24.1	13.5	3207	88
9.		Canon 1D X Mark III	Full Frame	20.0	5472	3648	4K/60p	24.2	14.5	3248	91
10.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
11.		Canon 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
12.		Canon 40D	APS-C	10.1	3888	2592	none	22.1	11.3	703	64
13.		Canon T1i	APS-C	15.1	4752	3168	1080/20p	21.7	11.5	663	63
14.		Canon T3	APS-C	12.2	4272	2848	720/30p	21.9	11.0	755	62
15.		Canon T4i	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
16.		Canon XTi	APS-C	10.1	3888	2592	none	22.1	11.0	664	62
17.		Nikon D3X	Full Frame	24.4	6048	4032	none	24.7	13.7	1992	88
Note: DXO values in italics represent estimates based on sensor size and age.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The 1Ds Mark III and the XSi 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 1Ds Mark III offers a wider field of view (100%) than the one in the XSi (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the 1Ds Mark III has a higher magnification (0.76x vs 0.54x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Canon 1Ds Mark III and Canon XSi along with similar information for a selection of comparators.

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 1Ds Mark III	optical	Y	3.0 / 230	fixed	n	1/8000s	5.0/s	n	n
2.		Canon XSi	optical	n	3.0 / 230	fixed	n	1/4000s	3.5/s	Y	n
3.		Canon 1D Mark III	optical	Y	3.0 / 230	fixed	n	1/8000s	10.0/s	n	n
4.		Canon 1Ds	optical	Y	2.0 / 120	fixed	n	1/8000s	3.0/s	n	n
5.		Canon 1Ds Mark II	optical	Y	2.0 / 230	fixed	n	1/8000s	4.0/s	n	n
6.		Canon 1D C	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
7.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
8.		Canon 1D X Mark II	optical	Y	3.2 / 1620	fixed	Y	1/8000s	16.0/s	n	n
9.		Canon 1D X Mark III	optical	Y	3.2 / 2100	fixed	Y	1/8000s	20.0/s	n	n
10.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
11.		Canon 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
12.		Canon 40D	optical	Y	3.0 / 230	fixed	n	1/8000s	6.5/s	Y	n
13.		Canon T1i	optical	n	3.0 / 920	fixed	n	1/4000s	3.4/s	Y	n
14.		Canon T3	optical	n	2.7 / 230	fixed	n	1/4000s	3.0/s	Y	n
15.		Canon T4i	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
16.		Canon XTi	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
17.		Nikon D3X	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the 1Ds Mark III, but is missing on the XSi is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The 1Ds Mark III writes its imaging data to Compact Flash or SDHC cards, while the XSi uses SDHC cards. The 1Ds Mark III features dual card slots, which can be very useful in case a memory card fails. In contrast, the XSi 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-1Ds Mark III and Canon EOS Rebel XSi 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 1Ds Mark III	Y	mono / -	-	-	-	2.0	-	-	-
2.		Canon XSi	Y	- / -	-	-	mini	2.0	-	-	-
3.		Canon 1D Mark III	Y	- / -	-	-	-	2.0	-	-	-
4.		Canon 1Ds	Y	- / -	-	-	-	FW	-	-	-
5.		Canon 1Ds Mark II	Y	- / -	-	-	-	2.0	-	-	-
6.		Canon 1D C	Y	mono / mono	Y	Y	mini	2.0	-	-	-
7.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
8.		Canon 1D X Mark II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
9.		Canon 1D X Mark III	Y	mono / mono	Y	Y	mini	3.1	Y	-	Y
10.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
11.		Canon 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
12.		Canon 40D	Y	- / -	-	-	-	2.0	-	-	-
13.		Canon T1i	Y	mono / mono	-	-	mini	2.0	-	-	-
14.		Canon T3	Y	stereo / mono	-	-	mini	2.0	-	-	-
15.		Canon T4i	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Canon XTi	Y	- / -	-	-	-	2.0	-	-	-
17.		Nikon D3X	Y	- / -	-	-	mini	2.0	-	-	-

Studio photographers will appreciate that the Canon 1Ds Mark III (unlike the XSi) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 1Ds Mark III and the XSi have been discontinued, but can regularly be found used on ebay. The 1Ds Mark III was replaced by the Canon 1DX, while the XSi was followed by the Canon T1i. Further information on the features and operation of the 1Ds Mark III and XSi can be found, respectively, in the Canon 1Ds Mark III Manual (free pdf) or the online Canon XSi Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Canon 1Ds Mark III or the Canon XSi – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Canon EOS-1Ds Mark III:

• More detail: Offers more megapixels (21 vs 12.2MP) with a 31% higher linear resolution.
• Better image quality: Scores substantially higher (19 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (2.1 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (1.2 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (1.3 stops ISO advantage).
• 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 (0.76x vs 0.54x).
• Easier setting verification: Features an LCD display on top to control shooting parameters.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (5 vs 3.5 flaps/sec) to capture the decisive moment.
• More portrait friendly: Features an integrated vertical grip for easier portrait shooting.
• Longer lasting: Can take more shots (1800 versus 500) on a single battery charge.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• 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 on the market for longer (launched in August 2007).

Advantages of the Canon EOS Rebel XSi:

• More compact: Is smaller (129x98mm vs 150x160mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 861g or 62 percent) and is thus easier to take along.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• More affordable: Was introduced into a lower priced category (90 percent cheaper at launch).
• More modern: Was introduced somewhat (5 months) more recently.

If the number of relative strengths (bullet points above) is taken as a guide, the 1Ds Mark III is the clear winner of the match-up (16 : 5 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 1Ds Mark III and the Canon XSi 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 1Ds Mark III and the XSi in practical situations. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable.

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 1Ds Mark III	..	..	..	+ +	4.5/5	..	Aug 2007	7,999	ebay.com
2.		Canon XSi	..	+ +	..	+ +	4/5	4.5/5	Jan 2008	799	ebay.com
3.		Canon 1D Mark III	..	..	..	..	..	..	Feb 2007	4,499	ebay.com
4.		Canon 1Ds	..	..	..	+ +	..	..	Sep 2002	8,999	ebay.com
5.		Canon 1Ds Mark II	..	..	..	+ +	..	..	Sep 2004	7,999	ebay.com
6.		Canon 1D C	..	..	..	..	..	..	Apr 2012	14,999	ebay.com
7.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
8.		Canon 1D X Mark II	..	..	4.5/5	89/100	4.5/5	4.5/5	Feb 2016	5,999	ebay.com
9.		Canon 1D X Mark III	..	+ +	5/5	..	4.5/5	4/5	Jan 2020	6,499	amazon.com
10.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
11.		Canon 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
12.		Canon 40D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2007	1,299	ebay.com
13.		Canon T1i	..	+ +	..	74/100	4.5/5	4.5/5	Mar 2009	799	ebay.com
14.		Canon T3	..	80/100	..	69/100	4/5	4.5/5	Feb 2011	449	ebay.com
15.		Canon T4i	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	849	ebay.com
16.		Canon XTi	..	+ +	..	+ +	o	4/5	Aug 2006	799	ebay.com
17.		Nikon D3X	..	..	..	86/100	4/5	5/5	Dec 2008	7,999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. A score, therefore, has to be seen in close connection to the price and market introduction time 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 make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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