Epson R-D1 vs Sony A900

The Epson R-D1 and the Sony Alpha A900 are two digital cameras that were announced, respectively, in March 2004 and September 2008. The R-D1 is a rangefinder-focusing mirrorless camera, while the A900 is a DSLR. The cameras are based on an APS-C (R-D1) and a full frame (A900) sensor. The Epson has a resolution of 6 megapixels, whereas the Sony provides 24.4 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		Sony A900
Rangefinder camera		Digital single lens reflex
Leica M mount lenses		Sony A mount lenses
6 MP – APS-C sensor		24.4 MP – Full Frame sensor
no Video		no Video
ISO 200-1,600		ISO 200-3,200 (100 - 6,400)
Optical viewfinder		Optical viewfinder
2.0" LCD – 235k dots		3.0" LCD – 922k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
1 shutter flaps per second		5 shutter flaps per second
no shake reduction		In-body stabilization
not weather sealed		Weathersealed body
142 x 89 x 40 mm, 620 g		156 x 117 x 82 mm, 895 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 Sony Alpha A900? 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 Sony A900 is provided in the side-by-side display below. 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.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A900 is considerably larger (44 percent) than the Epson R-D1. Moreover, the A900 is substantially heavier (44 percent) than the R-D1. It is noteworthy in this context that the A900 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 table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
3.		Canon Rebel	142 mm	99 mm	72 mm	649 g	400	n	Aug 2003	899	ebay.com
4.		Leica CL	131 mm	78 mm	45 mm	403 g	220	n	Nov 2017	2,795	ebay.com
5.		Leica M9	139 mm	80 mm	37 mm	585 g	550	n	Sep 2009	7,999	ebay.com
6.		Leica M10	139 mm	80 mm	39 mm	660 g	210	Y	Jan 2017	6,595	ebay.com
7.		Leica X Vario	133 mm	73 mm	95 mm	680 g	450	n	Jun 2013	2,850	ebay.com
8.		Leica X-U Typ 113	140 mm	79 mm	88 mm	635 g	450	Y	Jan 2016	2,950	ebay.com
9.		Nikon D40	124 mm	94 mm	64 mm	522 g	470	n	Nov 2006	499	ebay.com
10.		Nikon D50	133 mm	102 mm	76 mm	620 g	400	n	Apr 2005	749	ebay.com
11.		Nikon D70	140 mm	111 mm	78 mm	679 g	400	n	Jan 2004	999	ebay.com
12.		Nikon D70s	140 mm	111 mm	78 mm	679 g	500	n	Apr 2005	899	ebay.com
13.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
14.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
15.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
16.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
17.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	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 manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The two cameras under review were launched at the same price and fall into the same 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. A large sensor will generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have 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 tend to be more expensive and 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 Sony A900 a full frame sensor. The sensor area in the A900 is 133 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 24.4MP, the A900 offers a higher resolution than the R-D1 (6MP), but the A900 has smaller individual pixels (pixel pitch of 5.94μm versus 7.85μm for the R-D1). Yet, the A900 is a much more recent model (by 4 years and 6 months) 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.

The resolution advantage of the Sony A900 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A900 for good quality output (200 dots per inch) amounts to 30.2 x 20.2 inches or 76.8 x 51.2 cm, for very good quality (250 dpi) 24.2 x 16.1 inches or 61.4 x 41 cm, and for excellent quality (300 dpi) 20.2 x 13.4 inches or 51.2 x 34.1 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 Sony Alpha A900 are ISO 200 to ISO 3200, with the possibility to increase the ISO range to 100-6400.

In terms of underlying technology, the R-D1 is build around a CCD sensor, while the A900 uses a CMOS 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.

For many cameras, data on sensor performance has been reported by DXO Mark. 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 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.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
3.		Canon Rebel	APS-C	6.3	3072	2048	none	21.0	10.8	544	55
4.		Leica CL	APS-C	24.1	6014	4014	4K/30p	24.0	13.3	1788	82
5.		Leica M9	Full Frame	18.1	5212	3472	none	22.5	11.7	884	69
6.		Leica M10	Full Frame	23.8	5952	3992	none	24.4	13.2	2133	86
7.		Leica X Vario	APS-C	16.1	4928	3272	1080/30p	23.4	12.7	1320	78
8.		Leica X-U Typ 113	APS-C	16.1	4928	3264	1080/30p	23.8	13.0	1614	80
9.		Nikon D40	APS-C	6.0	3008	2000	none	21.0	11.0	561	56
10.		Nikon D50	APS-C	6.0	3008	2000	none	20.9	10.8	560	55
11.		Nikon D70	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
12.		Nikon D70s	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
13.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
14.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
15.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
16.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
17.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
Note: DXO values in italics represent estimates based on sensor size and age.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The R-D1 and the A900 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 Sony A900, 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.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
3.		Canon Rebel	optical	n	1.8 / 118	fixed	n	1/4000s	2.5/s	Y	n
4.		Leica CL	2360	Y	3.0 / 1040	fixed	Y	1/8000s	10.0/s	n	n
5.		Leica M9	optical	n	2.5 / 230	fixed	n	1/4000s	2.0/s	n	n
6.		Leica M10	optical	n	3.0 / 1037	fixed	n	1/4000s	5.0/s	n	n
7.		Leica X Vario	optional	n	3.0 / 920	fixed	n	1/2000s	5.0/s	Y	n
8.		Leica X-U Typ 113	optional	n	3.0 / 920	fixed	n	1/2000s	5.0/s	Y	n
9.		Nikon D40	optical	n	2.5 / 230	fixed	n	1/4000s	2.5/s	Y	n
10.		Nikon D50	optical	n	2.0 / 130	fixed	n	1/4000s	2.5/s	Y	n
11.		Nikon D70	optical	n	1.8 / 130	fixed	n	1/8000s	3.0/s	Y	n
12.		Nikon D70s	optical	n	2.0 / 130	fixed	n	1/8000s	3.0/s	Y	n
13.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
14.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
15.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
16.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
17.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the A900, 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 R-D1 writes its imaging data to SDHC cards, while the A900 uses Compact Flash or Memory Stick PRO Duo cards. The A900 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 Sony Alpha A900 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.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-
3.		Canon Rebel	Y	- / -	-	-	-	1.1	-	-	-
4.		Leica CL	Y	stereo / mono	-	-	-	-	Y	-	-
5.		Leica M9	Y	- / -	-	-	-	2.0	-	-	-
6.		Leica M10	Y	- / -	-	-	-	-	Y	-	-
7.		Leica X Vario	Y	stereo / mono	-	-	mini	2.0	-	-	-
8.		Leica X-U Typ 113	Y	stereo / mono	-	-	-	2.0	-	-	-
9.		Nikon D40	Y	- / -	-	-	-	2.0	-	-	-
10.		Nikon D50	Y	- / -	-	-	-	2.0	-	-	-
11.		Nikon D70	Y	- / -	-	-	-	1.0	-	-	-
12.		Nikon D70s	Y	- / -	-	-	-	2.0	-	-	-
13.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
14.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
15.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
16.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
17.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-

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 A900 have been discontinued, but can regularly be found used on ebay. The A900 was replaced by the Sony A99, while the R-D1 does not have a direct successor. Further information on the features and operation of the R-D1 and A900 can be found, respectively, in the Epson R-D1 Manual (free pdf) or the online Sony A900 Manual.

Review summary

So how do things add up? Is the Epson R-D1 better than the Sony A900 or vice versa? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Epson R-D1:

• More compact: Is smaller (142x89mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 275g or 31 percent) and hence easier to carry around.
• More heavily discounted: Has been available for much longer (launched in March 2004).

Arguments in favor of the Sony Alpha A900:

• More detail: Has more megapixels (24.4 vs 6MP), which boosts linear resolution by 101%.
• 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 (922k vs 235k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/2000s) to freeze action.
• Faster burst: Shoots at higher frequency (5 vs 1 flaps/sec) to capture the decisive moment.
• 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.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More modern: Reflects 4 years and 6 months of technical progress since the R-D1 launch.

If the count of relative strengths (bullet points above) is taken as a measure, the A900 is the clear winner of the contest (14 : 3 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.

In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the R-D1 or the A900 perform in practice. 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 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.		Epson R-D1	..	..	..	..	..	..	Mar 2004	2,999	ebay.com
2.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
3.		Canon Rebel	..	..	..	+ +	..	..	Aug 2003	899	ebay.com
4.		Leica CL	..	..	4.2/5	..	..	4/5	Nov 2017	2,795	ebay.com
5.		Leica M9	..	..	..	..	4.5/5	..	Sep 2009	7,999	ebay.com
6.		Leica M10	4.5/5	..	..	..	4/5	4.5/5	Jan 2017	6,595	ebay.com
7.		Leica X Vario	3/5	..	..	..	4/5	4/5	Jun 2013	2,850	ebay.com
8.		Leica X-U Typ 113	3.5/5	..	..	..	..	3.5/5	Jan 2016	2,950	ebay.com
9.		Nikon D40	..	81/100	..	+ +	o	4.5/5	Nov 2006	499	ebay.com
10.		Nikon D50	..	78/100	..	+ +	4/5	4.5/5	Apr 2005	749	ebay.com
11.		Nikon D70	..	..	..	+ +	..	..	Jan 2004	999	ebay.com
12.		Nikon D70s	..	..	..	..	..	5/5	Apr 2005	899	ebay.com
13.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
14.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
15.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
16.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
17.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, 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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