Sony A9 vs YI M1

The Sony Alpha A9 and the YI M1 are two digital cameras that were officially introduced, respectively, in April 2017 and September 2016. Both the A9 and the M1 are mirrorless interchangeable lens cameras that are based on a full frame (A9) and a Four Thirds (M1) sensor. The Sony has a resolution of 24 megapixels, whereas the YI provides 20.2 MP.

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

Headline Specifications

Sony A9		YI M1
Mirrorless system camera		Mirrorless system camera
Sony E mount lenses		Micro Four Thirds lenses
24 MP – Full Frame sensor		20.2 MP – Four Thirds sensor
4K/30p Video		4K/30p Video
ISO 100-51,200 (50 - 204,800)		ISO 100-25,600
Electronic viewfinder (3686k dots)		No viewfinder, LCD framing
3.0" LCD – 1440k dots		3.0" LCD – 1040k dots
Tilting touchscreen		Fixed touchscreen
20 shutter flaps per second		5 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		not weather sealed
650 shots per battery charge		450 shots per battery charge
127 x 96 x 63 mm, 673 g		114 x 64 x 34 mm, 281 g

Check A9 offers at
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Check M1 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A9 and the YI M1? 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

The side-by-side display below illustrates the physical size and weight of the Sony A9 and the YI M1. 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.

The M1 can be obtained in two different colors (black, silver), while the A9 is only available in black.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the YI M1 is considerably smaller (40 percent) than the Sony A9. Moreover, the M1 is substantially lighter (58 percent) than the A9. It is worth mentioning in this context that the A9 is splash and dust resistant, while the M1 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 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 Sony FE Lens Catalog (A9) and the Micro Four Thirds Lens Catalog (M1). 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 A9 gets 650 shots out of its Sony NP-FZ100 battery, while the M1 can take 450 images on a single charge of its YI BXM-10 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.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
2.		YI M1	114 mm	64 mm	34 mm	281 g	450	n	Sep 2016	349	ebay.com
3.		Canon SX730	110 mm	64 mm	40 mm	300 g	250	n	Apr 2017	399	ebay.com
4.		Fujifilm X-A3	117 mm	67 mm	40 mm	339 g	410	n	Aug 2016	399	ebay.com
5.		Nikon 1 J5	98 mm	60 mm	32 mm	231 g	250	n	Apr 2015	399	ebay.com
6.		Nikon Z6	134 mm	101 mm	67 mm	675 g	310	Y	Aug 2018	1,999	ebay.com
7.		Panasonic GF7	107 mm	65 mm	33 mm	266 g	230	n	Jan 2015	499	ebay.com
8.		Panasonic GX850	107 mm	65 mm	33 mm	269 g	210	n	Jan 2017	549	ebay.com
9.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999	ebay.com
10.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	1,999	amazon.com
11.		Sony A7R II	127 mm	96 mm	60 mm	625 g	290	Y	Jun 2015	3,199	ebay.com
12.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	3,199	ebay.com
13.		Sony A7R IIIA	127 mm	96 mm	74 mm	650 g	650	Y	Apr 2021	3,199	amazon.com
14.		Sony A7R V	131 mm	97 mm	82 mm	723 g	530	Y	Oct 2022	3,899	amazon.com
15.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
16.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	4,499	amazon.com
17.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The M1 was launched at a markedly lower price (by 92 percent) than the A9, 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 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. 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 Sony A9 features a full frame sensor and the YI M1 a Four Thirds sensor. The sensor area in the M1 is 73 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 2.0. The sensor in the A9 has a native 3:2 aspect ratio, while the one in the M1 offers a 4:3 aspect.

With 24MP, the A9 offers a higher resolution than the M1 (20.2MP), but the A9 nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 3.34μm for the M1) due to its larger sensor. Moreover, the A9 is a somewhat more recent model (by 6 months) than the M1, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels.

The resolution advantage of the Sony A9 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A9 for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the YI M1 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.

The A9 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Sony Alpha A9 has a native sensitivity range from ISO 100 to ISO 51200, which can be extended to ISO 50-204800. The corresponding ISO settings for the YI M1 are ISO 100 to ISO 25600 (no boost).

In terms of underlying technology, the A9 is build around a Stacked BSI-CMOS sensor, while the M1 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.

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"). 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.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
2.		YI M1	Four Thirds	20.2	5184	3888	4K/30p	23.0	12.6	1030	73
3.		Canon SX730	1/2.3	20.2	5184	3888	1080/60p	20.5	11.9	924	50
4.		Fujifilm X-A3	APS-C	24.0	6000	4000	1080/60p	23.8	13.1	1664	81
5.		Nikon 1 J5	1-inch	20.7	5568	3712	4K/15p	21.1	12.0	479	65
6.		Nikon Z6	Full Frame	24.3	6048	4024	4K/30p	25.3	14.3	3299	95
7.		Panasonic GF7	Four Thirds	15.8	4592	3448	1080/60p	22.7	12.3	874	70
8.		Panasonic GX850	Four Thirds	15.8	4592	3448	4K/30p	23.2	13.3	586	73
9.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
10.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
11.		Sony A7R II	Full Frame	42.2	7952	5304	4K/30p	26.0	13.9	3434	98
12.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
13.		Sony A7R IIIA	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
14.		Sony A7R V	Full Frame	60.2	9504	6336	8k/24p	26.5	14.8	3187	100
15.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
16.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
17.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
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 are equipped with sensors that have a sufficiently high read-out speed for moving images, and both provide the same movie specifications (4K/30p).

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A9 has an electronic viewfinder (3686k dots), which can be very helpful when shooting in bright sunlight. In contrast, the M1 relies on live view and the rear LCD for framing. The table below summarizes some of the other core capabilities of the Sony A9 and YI M1 in connection with corresponding information for a sample of similar 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.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
2.		YI M1	none	n	3.0 / 1040	fixed	Y	1/4000s	5.0/s	n	n
3.		Canon SX730	none	n	3.0 / 922	tilting	n	1/3200s	5.9/s	Y	Y
4.		Fujifilm X-A3	none	n	3.0 / 1040	tilting	Y	1/4000s	6.0/s	Y	n
5.		Nikon 1 J5	none	n	3.0 / 1037	tilting	Y	1/4000s	60.0/s	Y	n
6.		Nikon Z6	3690	Y	3.2 / 2100	tilting	Y	1/8000s	12.0/s	n	Y
7.		Panasonic GF7	none	n	3.0 / 1040	tilting	Y	1/500s	5.8/s	Y	n
8.		Panasonic GX850	none	n	3.0 / 1040	tilting	Y	1/500s	10.0/s	Y	n
9.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
10.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
11.		Sony A7R II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
12.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
13.		Sony A7R IIIA	3686	n	3.0 / 2340	tilting	Y	1/8000s	10.0/s	n	Y
14.		Sony A7R V	9440	n	3.2 / 2100	full-flex	Y	1/8000s	10.0/s	n	Y
15.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
16.		Sony A9 II	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
17.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the A9 and the M1 is in-body image stabilization (IBIS). The A9 reduces the risk of handshake-induced blur with all attached lenses, while the M1 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

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, the A9 is one of those camera that have an additional 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 YI M1 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 A9 writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the M1 uses SDXC cards. The A9 features dual card slots, which can be very useful in case a memory card fails. In contrast, the M1 only has one slot. The A9 supports UHS-II cards on its first slot and UHS-I on its second one, while the M1 cannot take advantage of Ultra High Speed SD cards.

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 Sony Alpha A9 and YI M1 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.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
2.		YI M1	Y	stereo / mono	-	-	micro	2.0	Y	-	Y
3.		Canon SX730	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
4.		Fujifilm X-A3	Y	stereo / mono	-	-	micro	2.0	Y	-	-
5.		Nikon 1 J5	-	stereo / mono	-	-	micro	2.0	Y	Y	-
6.		Nikon Z6	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
7.		Panasonic GF7	-	stereo / mono	-	-	micro	2.0	Y	Y	-
8.		Panasonic GX850	-	stereo / mono	-	-	micro	2.0	Y	-	-
9.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
10.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
11.		Sony A7R II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
12.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
13.		Sony A7R IIIA	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
14.		Sony A7R V	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
15.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
17.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-

It is notable that the A9 has a microphone port, which is missing on the M1. Such an external microphone input can help to substantially improve the quality of audio recordings when a good external microphone is used.

Studio photographers will appreciate that the Sony A9 (unlike the M1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the A9 and the M1 have been discontinued, but can regularly be found used on ebay. The A9 was replaced by the Sony A9 II, while the M1 does not have a direct successor. Further information on the features and operation of the A9 and M1 can be found, respectively, in the Sony A9 Manual (free pdf) or the online YI M1 Manual.

Review summary

So what conclusions can be drawn? Is the Sony A9 better than the YI M1 or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer the Sony Alpha A9:

• More detail: Offers more megapixels (24 vs 20.2MP) with a 11% higher linear resolution.
• Better image quality: Features a larger and more technologically advanced imaging 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.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Better sound: Can connect to an external microphone for higher quality sound recording.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• Easier framing: Has an electronic viewfinder for image composition and settings control.
• More detailed LCD: Has a higher resolution rear screen (1440k vs 1040k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (20 vs 5 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Longer lasting: Can take more shots (650 versus 450) on a single battery charge.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• 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.
• Faster buffer clearing: Supports Ultra High Speed (UHS-II and UHS-I) SDXC cards.
• More modern: Is somewhat more recent (announced 6 months after the M1).

Advantages of the YI M1:

• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (114x64mm vs 127x96mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 392g or 58 percent) and is thus easier to take along.
• More affordable: Was introduced into a lower priced category (92 percent cheaper at launch).
• More heavily discounted: Has been on the market for longer (launched in September 2016).

If the count of individual advantages (bullet points above) is taken as a guide, the A9 is the clear winner of the match-up (22 : 5 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 Sony A9 and the YI M1 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 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 A9 and the M1 in practical situations. 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 why expert reviews 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.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
2.		YI M1	..	..	..	69/100	..	..	Sep 2016	349	ebay.com
3.		Canon SX730	..	+	..	..	4/5	4/5	Apr 2017	399	ebay.com
4.		Fujifilm X-A3	..	..	..	74/100	4.5/5	4/5	Aug 2016	399	ebay.com
5.		Nikon 1 J5	..	..	..	..	4.5/5	4.5/5	Apr 2015	399	ebay.com
6.		Nikon Z6	5/5	..	5/5	89/100	4.5/5	5/5	Aug 2018	1,999	ebay.com
7.		Panasonic GF7	4/5	+	..	..	4.5/5	4.5/5	Jan 2015	499	ebay.com
8.		Panasonic GX850	..	+	..	76/100	4.5/5	4.5/5	Jan 2017	549	ebay.com
9.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	1,999	ebay.com
10.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	1,999	amazon.com
11.		Sony A7R II	5/5	+ +	5/5	90/100	5/5	5/5	Jun 2015	3,199	ebay.com
12.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	3,199	ebay.com
13.		Sony A7R IIIA	..	+ +	4/5	90/100	4.5/5	5/5	Apr 2021	3,199	amazon.com
14.		Sony A7R V	5/5	+ +	4.5/5	92/100	..	..	Oct 2022	3,899	amazon.com
15.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
16.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	4,499	amazon.com
17.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.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. Thus, a score needs to be put into the context of the launch date and the launch price 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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