Sony A5100 vs Panasonic GX9

The Sony Alpha A5100 and the Panasonic Lumix DC-GX9 are two digital cameras that were officially introduced, respectively, in August 2014 and February 2018. Both the A5100 and the GX9 are mirrorless interchangeable lens cameras that are based on an APS-C (A5100) and a Four Thirds (GX9) sensor. The Sony has a resolution of 24 megapixels, whereas the Panasonic 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 A5100		Panasonic GX9
Mirrorless system camera		Mirrorless system camera
Sony E mount lenses		Micro Four Thirds lenses
24 MP – APS-C sensor		20.2 MP – Four Thirds sensor
1080/60p Video		4K/30p Video
ISO 100-25,600		ISO 200-25,600
No viewfinder, LCD framing		Electronic viewfinder (2760k dots)
3.0" LCD – 922k dots		3.0" LCD – 1240k dots
Tilting touchscreen		Tilting touchscreen
6 shutter flaps per second		9 shutter flaps per second
Lens stabilization only		In-body stabilization
400 shots per battery charge		260 shots per battery charge
110 x 63 x 36 mm, 283 g		124 x 72 x 47 mm, 407 g

Check A5100 offers at
ebay.com
Check GX9 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A5100 and the Panasonic Lumix DC-GX9? 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 Sony A5100 and the Panasonic GX9 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.

The A5100 can be obtained in two different colors (black, white), while the GX9 is also available in two color-versions, but different ones (black, silver).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Panasonic GX9 is notably larger (29 percent) than the Sony A5100. Moreover, the GX9 is substantially heavier (44 percent) than the A5100. In this context, it is worth noting that neither the A5100 nor the GX9 are weather-sealed.

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 E-Mount Lens Catalog (A5100) and the Micro Four Thirds Lens Catalog (GX9). 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 A5100 gets 400 shots out of its Sony NP-FW50 battery, while the GX9 can take 260 images on a single charge of its Panasonic DMW-BLG10 power pack. The battery packs of both cameras can be charged via USB, which can be very convenient when travelling.

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.		Sony A5100	110 mm	63 mm	36 mm	283 g	400	n	Aug 2014	549	ebay.com
2.		Panasonic GX9	124 mm	72 mm	47 mm	407 g	260	n	Feb 2018	849	ebay.com
3.		Panasonic GX7	123 mm	71 mm	55 mm	402 g	350	n	Aug 2013	999	ebay.com
4.		Panasonic GX8	133 mm	78 mm	63 mm	487 g	330	Y	Jul 2015	1,199	ebay.com
5.		Panasonic GX85	122 mm	71 mm	44 mm	426 g	290	n	Apr 2016	799	amazon.com
6.		Panasonic LX100 II	115 mm	66 mm	65 mm	392 g	300	n	Aug 2018	999	ebay.com
7.		Panasonic ZS200	111 mm	65 mm	45 mm	340 g	370	n	Feb 2018	799	amazon.com
8.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	329	ebay.com
9.		Sony A5000	110 mm	63 mm	36 mm	269 g	420	n	Jan 2014	449	ebay.com
10.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	599	ebay.com
11.		Sony NEX-3	117 mm	62 mm	33 mm	297 g	330	n	May 2010	599	ebay.com
12.		Sony NEX-3N	110 mm	62 mm	35 mm	269 g	480	n	Feb 2013	499	ebay.com
13.		Sony NEX-5T	111 mm	59 mm	39 mm	276 g	330	n	Aug 2013	699	ebay.com
14.		Sony NEX-F3	117 mm	67 mm	42 mm	314 g	470	n	May 2012	599	ebay.com
15.		Sony RX100	102 mm	58 mm	36 mm	240 g	330	n	Jun 2012	649	ebay.com
16.		Sony RX100 II	102 mm	58 mm	38 mm	281 g	350	n	Jun 2013	749	ebay.com
17.		Sony RX100 IV	102 mm	58 mm	41 mm	298 g	280	n	Jun 2015	999	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
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The price is, of course, an important factor in any camera decision. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The A5100 was launched at a markedly lower price (by 35 percent) than the GX9, 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 sensor inside a digital camera is one of the key determinants 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. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better isolate a subject from the background. On the downside, larger sensors tend to be associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Sony A5100 features an APS-C sensor and the Panasonic GX9 a Four Thirds sensor. The sensor area in the GX9 is 39 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 2.0. The sensor in the A5100 has a native 3:2 aspect ratio, while the one in the GX9 offers a 4:3 aspect.

With 24MP, the A5100 offers a higher resolution than the GX9 (20.2MP), but the A5100 nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 3.34μm for the GX9) due to its larger sensor. However, the GX9 is a much more recent model (by 3 years and 5 months) than the A5100, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. Coming back to sensor resolution, it should be mentioned that the GX9 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Sony A5100 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A5100 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 Panasonic GX9 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 A5100 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Sony Alpha A5100 has a native sensitivity range from ISO 100 to ISO 25600. The corresponding ISO settings for the Panasonic Lumix DC-GX9 are ISO 200 to ISO 25600, with the possibility to increase the ISO range to 100-25600.

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) 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.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. This service assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. 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.		Sony A5100	APS-C	24.0	6000	4000	1080/60p	23.8	12.7	1347	80
2.		Panasonic GX9	Four Thirds	20.2	5184	3888	4K/30p	23.1	12.8	1163	74
3.		Panasonic GX7	Four Thirds	15.8	4592	3448	1080/60p	22.6	12.2	718	70
4.		Panasonic GX8	Four Thirds	20.2	5184	3888	4K/30p	23.5	12.6	806	75
5.		Panasonic GX85	Four Thirds	15.8	4592	3448	4K/30p	22.9	12.6	662	71
6.		Panasonic LX100 II	Four Thirds	16.8	4736	3552	4K/30p	22.8	12.7	979	72
7.		Panasonic ZS200	1-inch	20.0	5472	3648	4K/30p	22.0	12.2	449	64
8.		Sony A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
9.		Sony A5000	APS-C	19.8	5456	3632	1080/60i	23.8	13.0	1089	79
10.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
11.		Sony NEX-3	APS-C	14.0	4592	3056	720/30p	22.1	12.0	830	68
12.		Sony NEX-3N	APS-C	16.0	4912	3264	1080/60i	22.8	12.5	1067	74
13.		Sony NEX-5T	APS-C	16.0	4912	3264	1080/60p	23.6	13.0	1015	78
14.		Sony NEX-F3	APS-C	16.0	4912	3264	1080/60i	22.7	12.3	1114	73
15.		Sony RX100	1-inch	20.0	5472	3648	1080/60p	22.6	12.4	390	66
16.		Sony RX100 II	1-inch	20.0	5472	3648	1080/60p	22.5	12.4	483	67
17.		Sony RX100 IV	1-inch	20.0	5472	3648	4K/30p	22.8	12.6	591	70
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the GX9 provides a better video resolution than the A5100. It can shoot movie footage at 4K/30p, while the Sony is limited to 1080/60p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the GX9 has an electronic viewfinder (2760k dots), which can be very helpful when shooting in bright sunlight. In contrast, the A5100 relies on live view and the rear LCD for framing. The following table reports on some other key feature differences and similarities of the Sony A5100, the Panasonic GX9, 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.		Sony A5100	none	n	3.0 / 922	tilting	Y	1/4000s	6.0/s	Y	n
2.		Panasonic GX9	2760	n	3.0 / 1240	tilting	Y	1/4000s	9.0/s	Y	Y
3.		Panasonic GX7	2760	n	3.0 / 1040	tilting	Y	1/8000s	5.0/s	Y	Y
4.		Panasonic GX8	2360	n	3.0 / 1040	swivel	Y	1/8000s	10.0/s	n	Y
5.		Panasonic GX85	2765	n	3.0 / 1040	tilting	Y	1/4000s	8.0/s	Y	Y
6.		Panasonic LX100 II	2764	n	3.0 / 1240	fixed	Y	1/4000s	11.0/s	n	Y
7.		Panasonic ZS200	2330	n	3.0 / 1240	fixed	Y	1/2000s	10.0/s	Y	Y
8.		Sony A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
9.		Sony A5000	none	n	3.0 / 461	tilting	n	1/4000s	3.5/s	Y	n
10.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
11.		Sony NEX-3	optional	n	3.0 / 920	tilting	n	1/4000s	7.0/s	n	n
12.		Sony NEX-3N	optional	n	3.0 / 460	tilting	n	1/4000s	4.0/s	Y	n
13.		Sony NEX-5T	optional	n	3.0 / 922	tilting	Y	1/4000s	10.0/s	n	n
14.		Sony NEX-F3	optional	n	3.0 / 920	tilting	n	1/4000s	5.5/s	Y	n
15.		Sony RX100	none	n	3.0 / 1229	fixed	n	1/2000s	10.0/s	Y	Y
16.		Sony RX100 II	optional	n	3.0 / 1229	tilting	n	1/2000s	10.0/s	Y	Y
17.		Sony RX100 IV	2359	n	3.0 / 1228	tilting	n	1/2000s	16.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the GX9 and the A5100 is in-body image stabilization (IBIS). The GX9 reduces the risk of handshake-induced blur with all attached lenses, while the A5100 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 GX9 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 Panasonic GX9 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 A5100 writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the GX9 uses SDXC cards. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.

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 A5100 and Panasonic Lumix DC-GX9 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 A5100	-	stereo / mono	-	-	micro	2.0	Y	Y	-
2.		Panasonic GX9	Y	stereo / mono	-	-	micro	2.0	Y	-	Y
3.		Panasonic GX7	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
4.		Panasonic GX8	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
5.		Panasonic GX85	Y	stereo / mono	-	-	micro	2.0	Y	-	-
6.		Panasonic LX100 II	Y	stereo / mono	-	-	micro	2.0	Y	-	Y
7.		Panasonic ZS200	-	stereo / mono	-	-	micro	2.0	Y	-	Y
8.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Sony A5000	-	stereo / mono	-	-	micro	2.0	Y	Y	-
10.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
11.		Sony NEX-3	Y	stereo / mono	-	-	mini	2.0	-	-	-
12.		Sony NEX-3N	-	stereo / mono	-	-	micro	2.0	-	-	-
13.		Sony NEX-5T	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
14.		Sony NEX-F3	Y	stereo / mono	-	-	mini	2.0	-	-	-
15.		Sony RX100	-	stereo / mono	-	-	micro	2.0	-	-	-
16.		Sony RX100 II	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
17.		Sony RX100 IV	-	stereo / mono	-	-	micro	2.0	Y	Y	-

It is notable that the GX9 has a hotshoe, which makes it possible to easily attach optional accessories, such as an external flash gun. The A5100 does not feature such an accessory-socket.

Both the A5100 and the GX9 have been discontinued, but can regularly be found used on ebay. Neither of the two has a direct successor, so they represent the end of the respective camera lines from Sony and Panasonic. Further information on the features and operation of the A5100 and GX9 can be found, respectively, in the Sony A5100 Manual (free pdf) or the online Panasonic GX9 Manual.

Review summary

So what is the bottom line? Is there a clear favorite between the Sony A5100 and the Panasonic GX9? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Sony Alpha A5100:

• More detail: Offers more megapixels (24 vs 20.2MP) with a 11% higher linear resolution.
• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• More compact: Is smaller (110x63mm vs 124x72mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 124g or 30 percent) and hence easier to carry around.
• Longer lasting: Can take more shots (400 versus 260) on a single battery charge.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More affordable: Was introduced into a lower priced category (35 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2014).

Arguments in favor of the Panasonic Lumix DC-GX9:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• Easier framing: Has an electronic viewfinder for image composition and settings control.
• More detailed LCD: Has a higher resolution rear screen (1240k vs 922k dots).
• Faster burst: Shoots at higher frequency (9 vs 6 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• More modern: Reflects 3 years and 5 months of technical progress since the A5100 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the GX9 comes out slightly ahead of the A5100 (11 : 10 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.

How about other alternatives? Do the specifications of the Sony A5100 and the Panasonic GX9 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 incomplete and does no justice, for example, to the way the A5100 or the GX9 perform in practice. 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 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.		Sony A5100	4.5/5	+	..	..	4.5/5	5/5	Aug 2014	549	ebay.com
2.		Panasonic GX9	4/5	+	4/5	84/100	4.5/5	4.5/5	Feb 2018	849	ebay.com
3.		Panasonic GX7	4/5	+	..	79/100	5/5	5/5	Aug 2013	999	ebay.com
4.		Panasonic GX8	5/5	+	..	82/100	4.5/5	4.5/5	Jul 2015	1,199	ebay.com
5.		Panasonic GX85	4.5/5	+ +	..	82/100	5/5	5/5	Apr 2016	799	amazon.com
6.		Panasonic LX100 II	4.5/5	+	4.2/5	82/100	4.5/5	4.5/5	Aug 2018	999	ebay.com
7.		Panasonic ZS200	..	+ +	4.5/5	81/100	4.5/5	4.5/5	Feb 2018	799	amazon.com
8.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	329	ebay.com
9.		Sony A5000	3/5	+	..	..	4.5/5	4.5/5	Jan 2014	449	ebay.com
10.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	599	ebay.com
11.		Sony NEX-3	..	..	..	70/100	4.5/5	4/5	May 2010	599	ebay.com
12.		Sony NEX-3N	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	499	ebay.com
13.		Sony NEX-5T	..	..	..	..	4.5/5	4.5/5	Aug 2013	699	ebay.com
14.		Sony NEX-F3	4/5	..	..	74/100	4.5/5	4.5/5	May 2012	599	ebay.com
15.		Sony RX100	5/5	+ +	..	78/100	4/5	5/5	Jun 2012	649	ebay.com
16.		Sony RX100 II	5/5	+ +	..	79/100	4.5/5	4.5/5	Jun 2013	749	ebay.com
17.		Sony RX100 IV	4.5/5	+ +	..	85/100	4/5	4.5/5	Jun 2015	999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. Hence, a score should always be seen in the context of the camera's market launch date and its price, 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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