Epson R-D1 vs Pentax 645D

The Epson R-D1 and the Pentax 645D are two digital cameras that were officially introduced, respectively, in March 2004 and March 2010. The R-D1 is a rangefinder-focusing mirrorless camera, while the 645D is a DSLR. The cameras are based on an APS-C (R-D1) and a medium format (645D) sensor. The Epson has a resolution of 6 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

Epson R-D1		Pentax 645D
Rangefinder camera		Digital single lens reflex
Leica M mount lenses		Pentax 645 mount lenses
6 MP – APS-C sensor		39.5 MP – Medium Format sensor
no Video		no Video
ISO 200-1,600		ISO 100-1,600
Optical viewfinder		Optical viewfinder
2.0" LCD – 235k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
1 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
142 x 89 x 40 mm, 620 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 Epson R-D1 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 Epson R-D1 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 considerably larger (44 percent) than the Epson R-D1. Moreover, the 645D is substantially heavier (139 percent) than the R-D1. It is noteworthy in this context that the 645D is splash and dust-proof, while the R-D1 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.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.		Epson R-D1	142 mm	89 mm	40 mm	620 g	..	n	Mar 2004	2,999	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 IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
4.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
5.		Canon Rebel	142 mm	99 mm	72 mm	649 g	400	n	Aug 2003	899	ebay.com
6.		Leica CL	131 mm	78 mm	45 mm	403 g	220	n	Nov 2017	2,795	ebay.com
7.		Leica M9	139 mm	80 mm	37 mm	585 g	550	n	Sep 2009	7,999	ebay.com
8.		Leica M10	139 mm	80 mm	39 mm	660 g	210	Y	Jan 2017	6,595	ebay.com
9.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
10.		Leica X Vario	133 mm	73 mm	95 mm	680 g	450	n	Jun 2013	2,850	ebay.com
11.		Leica X-U Typ 113	140 mm	79 mm	88 mm	635 g	450	Y	Jan 2016	2,950	ebay.com
12.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
13.		Nikon D40	124 mm	94 mm	64 mm	522 g	470	n	Nov 2006	499	ebay.com
14.		Nikon D50	133 mm	102 mm	76 mm	620 g	400	n	Apr 2005	749	ebay.com
15.		Nikon D70	140 mm	111 mm	78 mm	679 g	400	n	Jan 2004	999	ebay.com
16.		Nikon D70s	140 mm	111 mm	78 mm	679 g	500	n	Apr 2005	899	ebay.com
17.		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 obviously take relative prices into account. 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 R-D1 was launched at a markedly lower price (by 70 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 sensor inside a digital camera is one of the key determinants 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. 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 Epson R-D1 features an APS-C sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 292 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 0.79. The sensor in the R-D1 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 R-D1 (6MP), but the 645D has smaller individual pixels (pixel pitch of 6.06μm versus 7.85μm for the R-D1). Yet, the 645D is a much more recent model (by 6 years) than the R-D1, 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 Epson R-D1 are 15 x 10 inches or 38.2 x 25.4 cm for good quality, 12 x 8 inches or 30.6 x 20.3 cm for very good quality, and 10 x 6.7 inches or 25.5 x 16.9 cm for excellent quality prints.

The Epson R-D1 has a native sensitivity range from ISO 200 to ISO 1600. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).

Technology-wise, both cameras are equipped with CCD (Charged Coupled Device) 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 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"). 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.		Epson R-D1	APS-C	6.0	3008	2000	none	21.1	10.4	564	55
2.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
3.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
4.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
5.		Canon Rebel	APS-C	6.3	3072	2048	none	21.0	10.8	544	55
6.		Leica CL	APS-C	24.1	6014	4014	4K/30p	24.0	13.3	1788	82
7.		Leica M9	Full Frame	18.1	5212	3472	none	22.5	11.7	884	69
8.		Leica M10	Full Frame	23.8	5952	3992	none	24.4	13.2	2133	86
9.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
10.		Leica X Vario	APS-C	16.1	4928	3272	1080/30p	23.4	12.7	1320	78
11.		Leica X-U Typ 113	APS-C	16.1	4928	3264	1080/30p	23.8	13.0	1614	80
12.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
13.		Nikon D40	APS-C	6.0	3008	2000	none	21.0	11.0	561	56
14.		Nikon D50	APS-C	6.0	3008	2000	none	20.9	10.8	560	55
15.		Nikon D70	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
16.		Nikon D70s	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
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 R-D1 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 following table reports on some other key feature differences and similarities of the Epson R-D1, 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.		Epson R-D1	optical	n	2.0 / 235	fixed	n	1/2000s	1.0/s	n	n
2.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
3.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
4.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
5.		Canon Rebel	optical	n	1.8 / 118	fixed	n	1/4000s	2.5/s	Y	n
6.		Leica CL	2360	Y	3.0 / 1040	fixed	Y	1/8000s	10.0/s	n	n
7.		Leica M9	optical	n	2.5 / 230	fixed	n	1/4000s	2.0/s	n	n
8.		Leica M10	optical	n	3.0 / 1037	fixed	n	1/4000s	5.0/s	n	n
9.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
10.		Leica X Vario	optional	n	3.0 / 920	fixed	n	1/2000s	5.0/s	Y	n
11.		Leica X-U Typ 113	optional	n	3.0 / 920	fixed	n	1/2000s	5.0/s	Y	n
12.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
13.		Nikon D40	optical	n	2.5 / 230	fixed	n	1/4000s	2.5/s	Y	n
14.		Nikon D50	optical	n	2.0 / 130	fixed	n	1/4000s	2.5/s	Y	n
15.		Nikon D70	optical	n	1.8 / 130	fixed	n	1/8000s	3.0/s	Y	n
16.		Nikon D70s	optical	n	2.0 / 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
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the 645D, but is missing on the R-D1 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 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 R-D1 writes its imaging data to SDHC 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 R-D1 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 Epson R-D1 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.		Epson R-D1	Y	- / -	-	-	-	-	-	-	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
4.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
5.		Canon Rebel	Y	- / -	-	-	-	1.1	-	-	-
6.		Leica CL	Y	stereo / mono	-	-	-	-	Y	-	-
7.		Leica M9	Y	- / -	-	-	-	2.0	-	-	-
8.		Leica M10	Y	- / -	-	-	-	-	Y	-	-
9.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
10.		Leica X Vario	Y	stereo / mono	-	-	mini	2.0	-	-	-
11.		Leica X-U Typ 113	Y	stereo / mono	-	-	-	2.0	-	-	-
12.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
13.		Nikon D40	Y	- / -	-	-	-	2.0	-	-	-
14.		Nikon D50	Y	- / -	-	-	-	2.0	-	-	-
15.		Nikon D70	Y	- / -	-	-	-	1.0	-	-	-
16.		Nikon D70s	Y	- / -	-	-	-	2.0	-	-	-
17.		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 R-D1 and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the R-D1 does not have a direct successor. Further information on the features and operation of the R-D1 and 645D can be found, respectively, in the Epson R-D1 Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Epson R-D1 and the Pentax 645D? Which camera is better? The listing below highlights the relative strengths of the two models.

Arguments in favor of the Epson R-D1:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• More compact: Is smaller (142x89mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 860g or 58 percent) and hence easier to carry around.
• More affordable: Was introduced into a lower priced category (70 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in March 2004).

Reasons to prefer the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 6MP), which boosts linear resolution by 151%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Is equipped with a larger and more technologically advanced sensor.
• Richer colors: The sensor size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger sensor captures a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger sensor produces good images even in poorly lit environments.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.0" vs 2.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 235k dots).
• Faster shutter: Has higher mechanical shutter speed (1/4000s vs 1/2000s) to freeze action.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More modern: Reflects 6 years of technical progress since the R-D1 launch.

If the count of relative strengths (bullet points above) is taken as a measure, the 645D is the clear winner of the contest (14 : 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 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.

In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it says little about, for example, the shooting experience and imaging performance of the R-D1 and the 645D 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 why hands-on reviews by experts 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.		Epson R-D1	..	..	..	..	..	..	Mar 2004	2,999	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
3.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
4.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
5.		Canon Rebel	..	..	..	+ +	..	..	Aug 2003	899	ebay.com
6.		Leica CL	..	..	4.2/5	..	..	4/5	Nov 2017	2,795	ebay.com
7.		Leica M9	..	..	..	..	4.5/5	..	Sep 2009	7,999	ebay.com
8.		Leica M10	4.5/5	..	..	..	4/5	4.5/5	Jan 2017	6,595	ebay.com
9.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
10.		Leica X Vario	3/5	..	..	..	4/5	4/5	Jun 2013	2,850	ebay.com
11.		Leica X-U Typ 113	3.5/5	..	..	..	..	3.5/5	Jan 2016	2,950	ebay.com
12.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
13.		Nikon D40	..	81/100	..	+ +	o	4.5/5	Nov 2006	499	ebay.com
14.		Nikon D50	..	78/100	..	+ +	4/5	4.5/5	Apr 2005	749	ebay.com
15.		Nikon D70	..	..	..	+ +	..	..	Jan 2004	999	ebay.com
16.		Nikon D70s	..	..	..	..	..	5/5	Apr 2005	899	ebay.com
17.		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.

Care should be taken when interpreting the review scores above, 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. 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

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 use the search menu below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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