Canon G1 X Mark III vs Sony A99

The Canon PowerShot G1 X Mark III and the Sony Alpha SLT-A99 are two digital cameras that were officially introduced, respectively, in October 2017 and September 2012. The G1X Mark III is a fixed lens compact, while the A99 is a DSLR. The cameras are based on an APS-C (G1X Mark III) and a full frame (A99) sensor. Both cameras offer a resolution of 24 megapixels.

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

Headline Specifications

Canon G1 X Mark III		Sony A99
Fixed lens compact camera		Digital single lens reflex
24-72mm f/2.8-5.6		Sony A mount lenses
24 MP – APS-C sensor		24 MP – Full Frame sensor
1080/60p Video		1080/60p Video
ISO 100-25,600		ISO 100-25,600
Electronic viewfinder (2360k dots)		Electronic viewfinder (2359k dots)
3.0" LCD – 1040k dots		3.0" LCD – 1229k dots
Swivel touchscreen		Fully flexible screen (no touchscreen)
9 shutter flaps per second		6 shutter flaps per second
Lens-based stabilization		In-body stabilization
Weathersealed body		Weathersealed body
200 shots per battery charge		500 shots per battery charge
115 x 78 x 51 mm, 399 g		147 x 111 x 78 mm, 812 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon PowerShot G1 X Mark III and the Sony Alpha SLT-A99? 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 Canon G1 X Mark III and the Sony A99. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. 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 A99 is considerably larger (82 percent) than the Canon G1 X Mark III. 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 and possibly misleading, as the G1X Mark III has a lens built in, whereas the A99 is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.

Concerning battery life, the G1X Mark III gets 200 shots out of its Canon NB-13L battery, while the A99 can take 500 images on a single charge of its Sony NP-FM500H power pack.

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.		Canon G1 X Mark III	115 mm	78 mm	51 mm	399 g	200	Y	Oct 2017	1,299	ebay.com
2.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
3.		Canon 6D Mark II	144 mm	111 mm	75 mm	765 g	1200	Y	Jun 2017	1,999	amazon.com
4.		Canon 80D	139 mm	105 mm	79 mm	730 g	960	Y	Feb 2016	1,199	ebay.com
5.		Canon SX540	120 mm	82 mm	92 mm	442 g	205	n	Jan 2016	399	ebay.com
6.		Fujifilm X-T3	133 mm	93 mm	59 mm	539 g	390	Y	Sep 2018	1,499	ebay.com
7.		Fujifilm X100F	127 mm	75 mm	52 mm	469 g	390	n	Jan 2017	1,299	ebay.com
8.		Fujifilm X100V	128 mm	75 mm	53 mm	478 g	420	Y	Feb 2020	1,399	ebay.com
9.		Nikon D7500	136 mm	104 mm	73 mm	720 g	950	Y	Apr 2017	1,299	amazon.com
10.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	4,499	amazon.com
11.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
12.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
13.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	ebay.com
14.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
15.		Sony A6300	120 mm	67 mm	49 mm	404 g	400	Y	Feb 2016	999	ebay.com
16.		Sony A6500	120 mm	67 mm	53 mm	453 g	350	Y	Oct 2016	1,399	ebay.com
17.		Sony RX10 III	133 mm	94 mm	127 mm	1051 g	420	Y	Mar 2016	1,499	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

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 G1X Mark III was launched at a lower price than the A99, despite having a lens built in. 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Canon G1 X Mark III features an APS-C sensor and the Sony A99 a full frame sensor. The sensor area in the A99 is 157 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.

Even though the A99 has a larger sensor, both cameras offer the same resolution of 24 megapixels. This implies that the A99 has a lower pixel density and larger individual pixels (with a pixel pitch of 5.96μm versus 3.72μm for the G1X Mark III), which gives it a potential advantage in terms of light gathering capacity. It should, however, be noted that the G1X Mark III is much more recent (by 5 years and 1 month) than the A99, and its sensor will have benefitted from technological advances during this time that at least partly compensate for the smaller pixel size.

The G1X Mark III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Canon PowerShot G1 X Mark III has a native sensitivity range from ISO 100 to ISO 25600. The corresponding ISO settings for the Sony Alpha SLT-A99 are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-25600.

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 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 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.		Canon G1 X Mark III	APS-C	24.0	6000	4000	1080/60p	23.8	13.2	1649	81
2.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
3.		Canon 6D Mark II	Full Frame	26.0	6240	4160	1080/60p	24.4	11.9	2862	85
4.		Canon 80D	APS-C	24.0	6000	4000	1080/60p	23.6	13.2	1135	79
5.		Canon SX540	1/2.3	20.2	5184	3888	1080/60p	20.3	11.7	806	48
6.		Fujifilm X-T3	APS-C	26.0	6240	4160	4K/60p	24.0	13.4	1853	83
7.		Fujifilm X100F	APS-C	24.0	6000	4000	1080/60p	23.9	13.2	1704	81
8.		Fujifilm X100V	APS-C	26.0	6240	4160	4K/30p	24.2	13.6	1996	84
9.		Nikon D7500	APS-C	20.7	5568	3712	4K/30p	24.3	14.0	1483	86
10.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
11.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
12.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
13.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
14.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
15.		Sony A6300	APS-C	24.0	6000	4000	4K/30p	24.4	13.7	1437	85
16.		Sony A6500	APS-C	24.0	6000	4000	4K/30p	24.5	13.7	1405	85
17.		Sony RX10 III	1-inch	20.0	5472	3648	4K/30p	23.1	12.6	472	70
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 also of capturing video footage. 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 (1080/60p).

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The two cameras under consideration are similar with respect to both having an electronic viewfinder. However, the one in the G1X Mark III offers a slightly higher resolution than the one in the A99 (2360k vs 2359k dots). The adjacent table lists some of the other core features of the Canon G1 X Mark III and Sony A99 along with similar information for a selection of comparators.

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.		Canon G1 X Mark III	2360	n	3.0 / 1040	swivel	Y	1/2000s	9.0/s	Y	Y
2.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
3.		Canon 6D Mark II	optical	Y	3.0 / 1040	swivel	Y	1/4000s	6.5/s	n	n
4.		Canon 80D	optical	Y	3.0 / 1040	swivel	Y	1/8000s	7.0/s	Y	n
5.		Canon SX540	none	n	3.0 / 461	fixed	n	1/2000s	5.9/s	Y	Y
6.		Fujifilm X-T3	3690	n	3.0 / 1040	full-flex	Y	1/8000s	11.0/s	n	n
7.		Fujifilm X100F	2360	n	3.0 / 1040	fixed	n	1/4000s	8.0/s	Y	n
8.		Fujifilm X100V	3690	n	3.0 / 1620	tilting	Y	1/4000s	11.0/s	n	n
9.		Nikon D7500	optical	Y	3.2 / 922	tilting	Y	1/8000s	8.0/s	Y	n
10.		Sony A9 II	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
11.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
12.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
13.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
14.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
15.		Sony A6300	2359	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
16.		Sony A6500	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	Y	Y
17.		Sony RX10 III	2359	Y	3.0 / 1229	tilting	n	1/2000s	14.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One difference between the cameras concerns the presence of an on-board flash. The G1X Mark III has one, while the A99 does not. While the built-in flash of the G1X Mark III is not very powerful, it can at times be useful as a fill-in light.

The Canon G1 X Mark III 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 G1X Mark III writes its imaging data to SDXC cards, while the A99 uses SDXC or Memory Stick PRO Duo cards. The A99 features dual card slots, which can be very useful in case a memory card fails. In contrast, the G1X Mark III only has one slot. 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 Canon PowerShot G1 X Mark III and Sony Alpha SLT-A99 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.		Canon G1 X Mark III	Y	stereo / mono	-	-	micro	2.0	Y	Y	Y
2.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
3.		Canon 6D Mark II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
4.		Canon 80D	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
5.		Canon SX540	-	stereo / mono	-	-	mini	2.0	Y	Y	-
6.		Fujifilm X-T3	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
7.		Fujifilm X100F	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
8.		Fujifilm X100V	Y	stereo / mono	Y	-	micro	3.1	Y	-	Y
9.		Nikon D7500	Y	stereo / mono	Y	Y	mini	2.0	Y	-	Y
10.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
11.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
12.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
13.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-
14.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-
15.		Sony A6300	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
16.		Sony A6500	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
17.		Sony RX10 III	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-

It is notable that the G1X Mark III offers wifi support, while the A99 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Studio photographers will appreciate that the Sony A99 (unlike the G1X Mark III) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Travel and landscape photographers will find it useful that the A99 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

Both the G1X Mark III and the A99 have been discontinued, but can regularly be found used on ebay. The A99 was replaced by the Sony A99, while the G1X Mark III does not have a direct successor. Further information on the features and operation of the G1X Mark III and A99 can be found, respectively, in the Canon G1 X Mark III Manual (free pdf) or the online Sony A99 Manual.

Review summary

So what conclusions can be drawn? Is the Canon G1 X Mark III better than the Sony A99 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Canon PowerShot G1 X Mark III:

• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• Faster burst: Shoots at higher frequency (9 vs 6 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Ready to shoot: Comes with a built-in lens, while the A99 requires a separate lens.
• More compact: Is smaller (115x78mm vs 147x111mm) and thus needs less room in the bag.
• Less heavy: Is lighter even though it comes with a built-in lens (unlike the A99).
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More modern: Reflects 5 years and 1 month of technical progress since the A99 launch.

Advantages of the Sony Alpha SLT-A99:

• 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 setting verification: Features a control panel on top to check shooting parameters.
• More detailed LCD: Has a higher resolution rear screen (1229k vs 1040k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/2000s) to freeze action.
• More flexible: Makes it possible to change lenses and thus to use specialty optics.
• Longer lasting: Gets more shots (500 versus 200) out of a single battery charge.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• 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.
• More heavily discounted: Has been around for much longer (launched in September 2012).

If the count of relative strengths (bullet points above) is taken as a measure, the G1X Mark III emerges as the winner of the contest (13 : 11 points). 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 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 Canon G1 X Mark III and the Sony A99 place the cameras among the top in their class? Find out in the latest Best Travel-Zoom Camera and Best DSLR Camera listings 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 says little about, for example, the shooting experience and imaging performance of the G1X Mark III and the A99 in practical situations. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.

Expert reviews

This is why expert reviews are important. 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.		Canon G1 X Mark III	5/5	+	4/5	79/100	4.5/5	4.5/5	Oct 2017	1,299	ebay.com
2.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
3.		Canon 6D Mark II	4/5	+	4/5	80/100	4.5/5	4/5	Jun 2017	1,999	amazon.com
4.		Canon 80D	4/5	+ +	4.5/5	84/100	4.5/5	4.5/5	Feb 2016	1,199	ebay.com
5.		Canon SX540	..	..	..	..	..	..	Jan 2016	399	ebay.com
6.		Fujifilm X-T3	5/5	+ +	4.5/5	88/100	5/5	5/5	Sep 2018	1,499	ebay.com
7.		Fujifilm X100F	5/5	+	3.9/5	83/100	4.5/5	4.5/5	Jan 2017	1,299	ebay.com
8.		Fujifilm X100V	5/5	+ +	4.5/5	86/100	5/5	4.5/5	Feb 2020	1,399	ebay.com
9.		Nikon D7500	4.5/5	+ +	4.5/5	86/100	5/5	4.5/5	Apr 2017	1,299	amazon.com
10.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	4,499	amazon.com
11.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
12.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
13.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
14.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
15.		Sony A6300	4.5/5	+	..	85/100	5/5	5/5	Feb 2016	999	ebay.com
16.		Sony A6500	5/5	+ +	3.5/5	85/100	4.5/5	4.5/5	Oct 2016	1,399	ebay.com
17.		Sony RX10 III	5/5	+	..	84/100	4.5/5	4.5/5	Mar 2016	1,499	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, please note that some of the review sites have changed their methodology and reporting over time.

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Other camera comparisons

Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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