Canon 1Ds Mark III vs Pentax 645D

The Canon EOS-1Ds Mark III and the Pentax 645D are two professional cameras that were announced, respectively, in August 2007 and March 2010. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a full frame (1Ds Mark III) and a medium format (645D) sensor. The Canon has a resolution of 21 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 1Ds Mark III		Pentax 645D
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Pentax 645 mount lenses
21 MP – Full Frame sensor		39.5 MP – Medium Format 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 – 921k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
5 shutter flaps per second		1.1 shutter flaps per second
Weathersealed body		Weathersealed body
1800 shots per battery charge		800 shots per battery charge
150 x 160 x 80 mm, 1385 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-1Ds Mark III 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 1Ds Mark III and the Pentax 645D is provided in the side-by-side display below. 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 smaller (24 percent) than the Canon 1Ds Mark III. However, the 645D is markedly heavier (7 percent) than the 1Ds Mark III. In this context, it is worth noting that both cameras are splash and dust-proof and can, hence, be used in inclement weather conditions or harsh environments.

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 1Ds Mark III gets 1800 shots out of its Canon LP-E4 battery, while the 645D can take 800 images on a single charge of its Pentax D-LI90 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.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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 1Ds Mark III	150 mm	160 mm	80 mm	1385 g	1800	Y	Aug 2007	7,999	ebay.com
2.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	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 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
5.		Canon 1Ds	156 mm	158 mm	80 mm	1265 g	600	Y	Sep 2002	8,999	ebay.com
6.		Canon 1Ds Mark II	156 mm	158 mm	80 mm	1215 g	1200	Y	Sep 2004	7,999	ebay.com
7.		Canon 1D C	158 mm	164 mm	83 mm	1545 g	1120	Y	Apr 2012	14,999	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 X Mark II	158 mm	168 mm	83 mm	1530 g	1210	Y	Feb 2016	5,999	ebay.com
10.		Canon 1D X Mark III	158 mm	168 mm	83 mm	1440 g	2850	Y	Jan 2020	6,499	amazon.com
11.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
12.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
13.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
14.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
15.		Nikon D3X	160 mm	157 mm	88 mm	1260 g	4400	Y	Dec 2008	7,999	ebay.com
16.		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 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 1Ds Mark III was launched at a somewhat lower price (by 20 percent) than the 645D, which makes it more attractive for photographers on a tight budget. 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. 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 are more costly to manufacture and tend to 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 Pentax 645D a medium format sensor. The sensor area in the 645D is 68 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 0.79. The sensor in the 1Ds Mark III 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 1Ds Mark III (21MP), but the 645D has smaller individual pixels (pixel pitch of 6.06μm versus 6.41μm for the 1Ds Mark III). Yet, the 645D is a much more recent model (by 2 years and 6 months) than the 1Ds Mark III, 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 1Ds Mark III are 28.1 x 18.7 inches or 71.3 x 47.5 cm for good quality, 22.5 x 15 inches or 57.1 x 38 cm for very good quality, and 18.7 x 12.5 inches or 47.5 x 31.7 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 Pentax 645D are ISO 100 to ISO 1600 (no boost).

In terms of underlying technology, the 1Ds Mark III 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 determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). The Overall DXO ratings for the two cameras under consideration are close, suggesting that they provide similar imaging performance. 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 1Ds Mark III	Full Frame	21.0	5616	3744	none	24.0	12.0	1663	80
2.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
3.		Canon 1D Mark III	APS-H	10.1	3888	2592	none	22.7	11.7	1078	71
4.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
5.		Canon 1Ds	Full Frame	11.0	4064	2704	none	21.8	11.0	954	63
6.		Canon 1Ds Mark II	Full Frame	16.6	4992	3328	none	23.3	11.3	1480	74
7.		Canon 1D C	Full Frame	17.9	5184	3456	4K/24p	24.3	13.0	2155	85
8.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
9.		Canon 1D X Mark II	Full Frame	20.0	5472	3648	4K/60p	24.1	13.5	3207	88
10.		Canon 1D X Mark III	Full Frame	20.0	5472	3648	4K/60p	24.2	14.5	3248	91
11.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
12.		Canon 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
13.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
14.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
15.		Nikon D3X	Full Frame	24.4	6048	4032	none	24.7	13.7	1992	88
16.		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.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The 1Ds Mark III 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 1Ds Mark III offers a wider field of view (100%) than the one in the 645D (98%), so that a larger proportion of the captured image is visible in the finder. On the other hand, the viewfinder of the 645D has a higher magnification (0.78x vs 0.76x), 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 1Ds Mark III, 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 1Ds Mark III	optical	Y	3.0 / 230	fixed	n	1/8000s	5.0/s	n	n
2.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
3.		Canon 1D Mark III	optical	Y	3.0 / 230	fixed	n	1/8000s	10.0/s	n	n
4.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
5.		Canon 1Ds	optical	Y	2.0 / 120	fixed	n	1/8000s	3.0/s	n	n
6.		Canon 1Ds Mark II	optical	Y	2.0 / 230	fixed	n	1/8000s	4.0/s	n	n
7.		Canon 1D C	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
8.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
9.		Canon 1D X Mark II	optical	Y	3.2 / 1620	fixed	Y	1/8000s	16.0/s	n	n
10.		Canon 1D X Mark III	optical	Y	3.2 / 2100	fixed	Y	1/8000s	20.0/s	n	n
11.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
12.		Canon 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
13.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
14.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
15.		Nikon D3X	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	n
16.		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.

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 1Ds Mark III writes its imaging data to Compact Flash or SDHC cards, while the 645D uses SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails.

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 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 1Ds Mark III	Y	mono / -	-	-	-	2.0	-	-	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 1D Mark III	Y	- / -	-	-	-	2.0	-	-	-
4.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
5.		Canon 1Ds	Y	- / -	-	-	-	FW	-	-	-
6.		Canon 1Ds Mark II	Y	- / -	-	-	-	2.0	-	-	-
7.		Canon 1D C	Y	mono / mono	Y	Y	mini	2.0	-	-	-
8.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
9.		Canon 1D X Mark II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
10.		Canon 1D X Mark III	Y	mono / mono	Y	Y	mini	3.1	Y	-	Y
11.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
12.		Canon 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
13.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
14.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
15.		Nikon D3X	Y	- / -	-	-	mini	2.0	-	-	-
16.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.

Both the 1Ds Mark III and the 645D have been discontinued, but can regularly be found used on ebay. The 1Ds Mark III was replaced by the Canon 1DX, while the 645D was followed by the Pentax 645Z. Further information on the features and operation of the 1Ds Mark III and 645D can be found, respectively, in the Canon 1Ds Mark III Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So how do things add up? Which of the two cameras – the Canon 1Ds Mark III or the Pentax 645D – 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:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better low-light sensitivity: Requires less light for good images (0.4 stops ISO advantage).
• More complete view: Has a viewfinder with a larger field of view (100% vs 98%).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (5 vs 1.1 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 800) on a single battery charge.
• More affordable: Was introduced into a lower priced segment (20 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2007).

Reasons to prefer the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 21MP), which boosts linear resolution by 34%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• More dynamic range: Captures a broader range of light and dark details (0.6 EV of extra DR).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.76x).
• 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.
• More compact: Is smaller (156x117mm vs 150x160mm) and will fit more readily into a bag.
• More modern: Reflects 2 years and 6 months of technical progress since the 1Ds Mark III launch.

If the count of relative strengths (bullet points above) is taken as a measure, the 1Ds Mark III comes out slightly ahead of the 645D (9 : 8 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 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 1Ds Mark III 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 remains incomplete and does no justice, for example, to the way the 1Ds Mark III or the 645D perform in practice. 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 why expert reviews 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 1Ds Mark III	..	..	..	+ +	4.5/5	..	Aug 2007	7,999	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
3.		Canon 1D Mark III	..	..	..	..	..	..	Feb 2007	4,499	ebay.com
4.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
5.		Canon 1Ds	..	..	..	+ +	..	..	Sep 2002	8,999	ebay.com
6.		Canon 1Ds Mark II	..	..	..	+ +	..	..	Sep 2004	7,999	ebay.com
7.		Canon 1D C	..	..	..	..	..	..	Apr 2012	14,999	ebay.com
8.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
9.		Canon 1D X Mark II	..	..	4.5/5	89/100	4.5/5	4.5/5	Feb 2016	5,999	ebay.com
10.		Canon 1D X Mark III	..	+ +	5/5	..	4.5/5	4/5	Jan 2020	6,499	amazon.com
11.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
12.		Canon 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
13.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
14.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
15.		Nikon D3X	..	..	..	86/100	4/5	5/5	Dec 2008	7,999	ebay.com
16.		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 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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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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