OM System OM-1 vs Sony A7R IV

The OM System OM-1 and the Sony Alpha A7R IV are two enthusiast cameras that were announced, respectively, in February 2022 and July 2019. Both the OM-1 and the A7R IV are mirrorless interchangeable lens cameras that are based on a Four Thirds (OM-1) and a full frame (A7R IV) sensor. The OM System has a resolution of 20.2 megapixels, whereas the Sony provides 60.2 MP.

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

Headline Specifications

OM System OM-1		Sony A7R IV
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Sony E mount lenses
20.2 MP – Four Thirds sensor		60.2 MP – Full Frame sensor
4K/60p Video		4K/30p Video
ISO 80-25,600 (80 - 102,400)		ISO 100-32,000 (50 - 102,400)
Electronic viewfinder (5760k dots)		Electronic viewfinder (5760k dots)
3.0" LCD – 1640k dots		3.0" LCD – 1440k dots
Swivel touchscreen		Tilting touchscreen
10 shutter flaps per second		10 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
520 shots per battery charge		670 shots per battery charge
135 x 92 x 73 mm, 599 g		129 x 96 x 78 mm, 665 g

Check OM-1 offers at
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Check A7R IV offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the OM System OM-1 and the Sony Alpha A7R IV? 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 OM System OM-1 and the Sony A7R IV 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 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 OM System OM-1 and the Sony A7R IV are of equal size. However, the A7R IV is markedly heavier (11 percent) than the OM-1. 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. A larger imaging sensor will tend to go along with bigger and heavier lenses, although exceptions exist. You can compare the optics available for the two cameras in the Micro Four Thirds Lens Catalog (OM-1) and the Sony FE Lens Catalog (A7R IV). Mirrorless cameras, such as the two under consideration, have the additional advantage of having a short flange to focal plane distance, which makes it possible to mount many lenses from other systems onto the camera via adapters.

Concerning battery life, the OM-1 gets 520 shots out of its OM System BLX-1 battery, while the A7R IV can take 670 images on a single charge of its Sony NP-FZ100 power pack. The battery packs of both cameras can be charged via USB, which can be very convenient when travelling.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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.		OM System OM-1	135 mm	92 mm	73 mm	599 g	520	Y	Feb 2022	2,199	ebay.com
2.		Sony A7R IV	129 mm	96 mm	78 mm	665 g	670	Y	Jul 2019	3,499	ebay.com
3.		Olympus E-M1 II	134 mm	91 mm	67 mm	574 g	440	Y	Sep 2016	1,999	ebay.com
4.		Olympus E-M1 III	134 mm	91 mm	69 mm	580 g	420	Y	Feb 2020	1,799	ebay.com
5.		OM System OM-1 II	135 mm	92 mm	73 mm	599 g	500	Y	Jan 2024	2,399	amazon.com
6.		OM System OM-5	125 mm	85 mm	50 mm	414 g	310	Y	Oct 2022	1,199	amazon.com
7.		Panasonic G9	137 mm	97 mm	92 mm	658 g	400	Y	Nov 2017	1,699	ebay.com
8.		Panasonic G9 II	134 mm	102 mm	90 mm	658 g	390	Y	Sep 2023	1,899	amazon.com
9.		Panasonic G95	130 mm	94 mm	77 mm	536 g	290	Y	Apr 2019	999	ebay.com
10.		Panasonic GH5	139 mm	98 mm	87 mm	725 g	410	Y	Jan 2017	1,999	ebay.com
11.		Panasonic GH5 II	139 mm	98 mm	87 mm	727 g	400	Y	May 2021	1,699	amazon.com
12.		Panasonic GH6	138 mm	100 mm	100 mm	823 g	360	Y	Feb 2022	2,199	amazon.com
13.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	1,999	amazon.com
14.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	3,199	ebay.com
15.		Sony A7R IVA	129 mm	96 mm	78 mm	665 g	670	Y	Apr 2021	3,499	amazon.com
16.		Sony A7S III	127 mm	97 mm	81 mm	699 g	600	Y	Jul 2020	3,499	amazon.com
17.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	4,499	amazon.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 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 OM-1 was launched at a markedly lower price (by 37 percent) than the A7R IV, 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its 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 OM System OM-1 features a Four Thirds sensor and the Sony A7R IV a full frame sensor. The sensor area in the A7R IV is 278 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.0. The sensor in the OM-1 has a native 4:3 aspect ratio, while the one in the A7R IV offers a 3:2 aspect.

With 60.2MP, the A7R IV offers a higher resolution than the OM-1 (20.2MP), but the A7R IV nevertheless has larger individual pixels (pixel pitch of 3.76μm versus 3.34μm for the OM-1) due to its larger sensor. However, the OM-1 is a much more recent model (by 2 years and 7 months) than the A7R IV, 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 neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

The resolution advantage of the Sony A7R IV implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7R IV for good quality output (200 dots per inch) amounts to 47.5 x 31.7 inches or 120.7 x 80.5 cm, for very good quality (250 dpi) 38 x 25.3 inches or 96.6 x 64.4 cm, and for excellent quality (300 dpi) 31.7 x 21.1 inches or 80.5 x 53.6 cm. The corresponding values for the OM System OM-1 are 25.9 x 19.4 inches or 65.8 x 49.4 cm for good quality, 20.7 x 15.6 inches or 52.7 x 39.5 cm for very good quality, and 17.3 x 13 inches or 43.9 x 32.9 cm for excellent quality prints.

Both cameras have the capacity to capture high quality composite images by combining multiple shots after shifting the sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

The OM System OM-1 has a native sensitivity range from ISO 80 to ISO 25600, which can be extended to ISO 80-102400. The corresponding ISO settings for the Sony Alpha A7R IV are ISO 100 to ISO 32000, with the possibility to increase the ISO range to 50-102400.

In terms of underlying technology, the OM-1 is build around a Stacked BSI-CMOS sensor, while the A7R IV uses a BSI-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.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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.		OM System OM-1	Four Thirds	20.2	5184	3888	4K/60p	23.4	13.4	1553	77
2.		Sony A7R IV	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
3.		Olympus E-M1 II	Four Thirds	20.2	5184	3888	4K/30p	23.7	12.8	1312	80
4.		Olympus E-M1 III	Four Thirds	20.2	5184	3888	4K/30p	23.3	13.1	1356	76
5.		OM System OM-1 II	Four Thirds	20.2	5184	3888	4K/60p	23.4	13.6	1749	78
6.		OM System OM-5	Four Thirds	20.2	5184	3888	4K/30p	23.4	13.4	1622	78
7.		Panasonic G9	Four Thirds	20.2	5184	3888	4K/60p	23.1	12.8	1138	74
8.		Panasonic G9 II	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.5	1710	78
9.		Panasonic G95	Four Thirds	20.2	5184	3888	4K/30p	23.2	13.0	1273	75
10.		Panasonic GH5	Four Thirds	20.2	5184	3888	4K/60p	23.9	13.0	807	77
11.		Panasonic GH5 II	Four Thirds	20.2	5184	3888	4K/60p	23.7	13.1	1136	79
12.		Panasonic GH6	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.4	1555	77
13.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
14.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
15.		Sony A7R IVA	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
16.		Sony A7S III	Full Frame	12.0	4240	2832	4K/120p	23.7	13.9	2520	86
17.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
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 can also record movies. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the OM-1 provides a higher frame rate than the A7R IV. It can shoot video footage at 4K/60p, while the Sony is limited to 4K/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The OM-1 and the A7R IV are similar in the sense that both feature an electronic viewfinder, which is helpful when framing images in bright sunlight. Moreover, their viewfinders offer an identical resolution of 5760k dots. The following table reports on some other key feature differences and similarities of the OM System OM-1, the Sony A7R IV, 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.		OM System OM-1	5760	n	3.0 / 1640	swivel	Y	1/8000s	10.0/s	n	Y
2.		Sony A7R IV	5760	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
3.		Olympus E-M1 II	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
4.		Olympus E-M1 III	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
5.		OM System OM-1 II	5760	n	3.0 / 1640	swivel	Y	1/8000s	10.0/s	n	Y
6.		OM System OM-5	2360	n	3.0 / 1040	swivel	Y	1/8000s	10.0/s	n	Y
7.		Panasonic G9	3680	Y	3.0 / 1040	swivel	Y	1/8000s	20.0/s	n	Y
8.		Panasonic G9 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	10.0/s	n	Y
9.		Panasonic G95	2360	n	3.0 / 1240	swivel	Y	1/4000s	9.0/s	Y	Y
10.		Panasonic GH5	3680	n	3.2 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
11.		Panasonic GH5 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	12.0/s	n	Y
12.		Panasonic GH6	3680	n	3.0 / 1840	full-flex	Y	1/8000s	14.0/s	n	Y
13.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
14.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
15.		Sony A7R IVA	5760	n	3.0 / 2340	tilting	Y	1/8000s	10.0/s	n	Y
16.		Sony A7S III	9440	n	3.0 / 1440	swivel	Y	1/8000s	10.0/s	n	Y
17.		Sony A9 II	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, both cameras under consideration feature an electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).

The OM System OM-1 and the Sony A7R IV both have 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.

Concerning the storage of imaging data, both the OM-1 and the A7R IV write their files to SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. Moreover, both the OM-1 and the A7R IV support UHS-II cards, which provide for Ultra High Speed data transfer of up to 312 MB/s, on both slots.

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 OM System OM-1 and Sony Alpha A7R IV 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.		OM System OM-1	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
2.		Sony A7R IV	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
3.		Olympus E-M1 II	Y	stereo / mono	Y	Y	micro	3.0	Y	-	-
4.		Olympus E-M1 III	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
5.		OM System OM-1 II	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
6.		OM System OM-5	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
7.		Panasonic G9	Y	stereo / mono	Y	Y	full	3.0	Y	-	Y
8.		Panasonic G9 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
9.		Panasonic G95	Y	stereo / mono	Y	Y	micro	2.0	Y	-	Y
10.		Panasonic GH5	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
11.		Panasonic GH5 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
12.		Panasonic GH6	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
13.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
14.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
15.		Sony A7R IVA	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
16.		Sony A7S III	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
17.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y

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

Both the OM-1 and the A7R IV have been discontinued, but can regularly be found used on ebay. The A7R IV was replaced by the Sony A7R V, while the OM-1 was followed by the OM System OM-1 II. Further information on the features and operation of the OM-1 and A7R IV can be found, respectively, in the OM System OM-1 Manual (free pdf) or the online Sony A7R IV Manual.

Review summary

So how do things add up? Which of the two cameras – the OM System OM-1 or the Sony A7R IV – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the OM System OM-1:

• Better video: Provides higher movie framerates (4K/60p versus 4K/30p).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.82x vs 0.78x).
• More detailed LCD: Has a higher resolution rear screen (1640k vs 1440k dots).
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Less heavy: Is lighter (by 66g or 10 percent) and hence easier to carry around.
• More affordable: Was introduced into a lower priced category (37 percent cheaper at launch).
• More modern: Reflects 2 years and 7 months of technical progress since the A7R IV launch.

Advantages of the Sony Alpha A7R IV:

• More detail: Has more megapixels (60.2 vs 20.2MP), which boosts linear resolution by 76%.
• Better image quality: Features bigger pixels on a larger sensor for higher quality imaging.
• Richer colors: The pixel size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger pixels capture a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger pixels means good image quality even under poor lighting.
• Longer lasting: Gets more shots (670 versus 520) out of a single battery charge.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More heavily discounted: Has been around for much longer (launched in July 2019).

If the count of individual advantages (bullet points above) is taken as a guide, the match-up finishes in a tie (8 points each). However, the relevance of individual strengths will vary across photographers, so that you might want to apply your own weighing scheme to the summary points when reflecting and deciding 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 OM System OM-1 and the Sony A7R IV place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens 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 OM-1 or the A7R IV. 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 where reviews by experts come in. 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.		OM System OM-1	5/5	..	..	87/100	5/5	4.5/5	Feb 2022	2,199	ebay.com
2.		Sony A7R IV	5/5	+	4.5/5	91/100	4.5/5	5/5	Jul 2019	3,499	ebay.com
3.		Olympus E-M1 II	5/5	+ +	5/5	85/100	4.5/5	4.5/5	Sep 2016	1,999	ebay.com
4.		Olympus E-M1 III	5/5	..	5/5	83/100	4.5/5	4/5	Feb 2020	1,799	ebay.com
5.		OM System OM-1 II	..	..	..	..	..	..	Jan 2024	2,399	amazon.com
6.		OM System OM-5	5/5	..	4.5/5	83/100	5/5	4.5/5	Oct 2022	1,199	amazon.com
7.		Panasonic G9	..	+ +	5/5	85/100	5/5	5/5	Nov 2017	1,699	ebay.com
8.		Panasonic G9 II	5/5	..	4.5/5	87/100	..	4.5/5	Sep 2023	1,899	amazon.com
9.		Panasonic G95	4.5/5	+	4.5/5	83/100	4.5/5	4.5/5	Apr 2019	999	ebay.com
10.		Panasonic GH5	4.5/5	+ +	..	85/100	4.5/5	5/5	Jan 2017	1,999	ebay.com
11.		Panasonic GH5 II	4.5/5	..	4.5/5	85/100	4.5/5	5/5	May 2021	1,699	amazon.com
12.		Panasonic GH6	5/5	+ +	5/5	87/100	5/5	5/5	Feb 2022	2,199	amazon.com
13.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	1,999	amazon.com
14.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	3,199	ebay.com
15.		Sony A7R IVA	5/5	+	4.5/5	91/100	4.5/5	5/5	Apr 2021	3,499	amazon.com
16.		Sony A7S III	4.5/5	+ +	5/5	91/100	4.5/5	5/5	Jul 2020	3,499	amazon.com
17.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	4,499	amazon.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The assessments were made in relation to similar cameras of the same technological generation. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date 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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