Sigma fp vs Sony RX1R III

The Sigma fp and the Sony Cyber-shot DSC-RX1R III are two digital cameras that were revealed to the public, respectively, in July 2019 and July 2025. The fp is a mirrorless interchangeable lens camera, while the RX1R III is a fixed lens compact. Both cameras are equipped with a full frame sensor. The Sigma has a resolution of 24 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

Sigma fp		Sony RX1R III
Mirrorless system camera		Fixed lens compact camera
Leica L mount lenses		35mm f/2.0
24 MP – Full Frame sensor		60.2 MP – Full Frame sensor
4K/30p Video		4K/30p Video
ISO 100-25,600 (6 - 102,400)		ISO 100-32,000 (50 - 102,400)
Viewfinder optional		Electronic viewfinder (2360k dots)
3.2" LCD – 2100k dots		3.0" LCD – 2360k dots
Fixed touchscreen		Fixed touchscreen
12 shutter flaps per second		5 shutter flaps per second
Weathersealed body		Weathersealed body
280 shots per battery charge		300 shots per battery charge
113 x 70 x 45 mm, 422 g		113 x 68 x 88 mm, 498 g

Check fp price at
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Check RX1R III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sigma fp and the Sony Cyber-shot DSC-RX1R III? 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 Sigma fp and the Sony RX1R III. 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 RX1R III is somewhat smaller (3 percent) than the Sigma fp. 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 RX1R III has a lens built in, whereas the fp 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 fp gets 280 shots out of its Sigma BP-51 battery, while the RX1R III can take 300 images on a single charge of its Sony NP-FW50 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 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	Street Price
1.		Sigma fp	113 mm	70 mm	45 mm	422 g	280	Y	Jul 2019	US$ 1 899	amazon.com
2.		Sony RX1R III	113 mm	68 mm	88 mm	498 g	300	Y	Jul 2025	US$ 5 099	amazon.com
3.		Fujifilm X-Pro3	141 mm	83 mm	46 mm	497 g	440	Y	Oct 2019	US$ 1 799	amazon.com
4.		Leica Q3	130 mm	80 mm	93 mm	743 g	350	Y	May 2023	US$ 5 999	amazon.com
5.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	US$ 7 449	ebay.com
6.		Nikon D780	144 mm	116 mm	76 mm	840 g	2260	Y	Jan 2020	US$ 2 299	amazon.com
7.		Panasonic S1	149 mm	110 mm	97 mm	1017 g	400	Y	Feb 2019	US$ 2 499	ebay.com
8.		Panasonic S1H	151 mm	114 mm	110 mm	1052 g	400	Y	May 2019	US$ 3 999	amazon.com
9.		Panasonic S5	133 mm	98 mm	82 mm	714 g	440	Y	Sep 2020	US$ 1 999	amazon.com
10.		Panasonic TS7	117 mm	76 mm	37 mm	319 g	300	Y	May 2018	US$ 449	ebay.com
11.		Sigma fp L	113 mm	70 mm	45 mm	427 g	240	Y	Mar 2021	US$ 2 499	amazon.com
12.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	US$ 1 699	ebay.com
13.		Sony A7C	124 mm	71 mm	60 mm	509 g	740	Y	Sep 2020	US$ 1 799	amazon.com
14.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	US$ 2 299	ebay.com
15.		Sony A7S	127 mm	94 mm	48 mm	489 g	380	Y	Apr 2014	US$ 2 499	ebay.com
16.		Sony RX1R II	113 mm	65 mm	72 mm	507 g	220	n	Oct 2015	US$ 3 299	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 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. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Both cameras under consideration feature a full frame sensor, but their sensors differ slightly in size. The sensor area in the RX1R III is 1 percent smaller. They nevertheless have the same format factor of 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Despite having a slightly smaller sensor, the RX1R III offers a higher resolution of 60.2 megapixels, compared with 24 MP of the fp. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.76μm versus 5.98μm for the fp). However, it should be noted that the RX1R III is much more recent (by 6 years) than the fp, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. 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 RX1R III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the RX1R III 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 Sigma fp are 30 x 20 inches or 76.2 x 50.8 cm for good quality, 24 x 16 inches or 61 x 40.6 cm for very good quality, and 20 x 13.3 inches or 50.8 x 33.9 cm for excellent quality prints.

The RX1R III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Sigma fp has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 6-102400. The corresponding ISO settings for the Sony Cyber-shot DSC-RX1R III are ISO 100 to ISO 32000, with the possibility to increase the ISO range to 50-102400.

Technology-wise, both cameras are equipped with BSI-CMOS (Backside Illuminated 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 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.		Sigma fp	Full Frame	24.0	6000	4000	4K/30p	25.2	14.2	2829	94
2.		Sony RX1R III	Full Frame	60.2	9504	6336	4K/30p	25.4	14.9	3417	97
3.		Fujifilm X-Pro3	APS-C	26.0	6240	4160	4K/30p	24.1	13.6	1968	84
4.		Leica Q3	Full Frame	60.3	9528	6328	8K/30p	25.4	14.7	3216	96
5.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
6.		Nikon D780	Full Frame	24.3	6048	4024	4K/30p	25.3	14.3	2877	95
7.		Panasonic S1	Full Frame	24.0	6000	4000	4K/60p	25.2	14.5	3333	95
8.		Panasonic S1H	Full Frame	24.0	6000	4000	6K/30p	25.2	14.2	2805	94
9.		Panasonic S5	Full Frame	24.0	6000	4000	4K/60p	25.1	14.5	2697	94
10.		Panasonic TS7	1/2.3	20.2	5184	3888	4K/30p	20.6	12.1	1028	51
11.		Sigma fp L	Full Frame	60.2	9520	6328	4K/30p	25.3	14.4	3001	96
12.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90
13.		Sony A7C	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3407	95
14.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95
15.		Sony A7S	Full Frame	12.0	4240	2832	1080/60p	23.9	13.2	3702	87
16.		Sony RX1R II	Full Frame	42.2	7952	5304	1080/60p	25.8	13.9	3204	97
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 have a sensor with sufficiently fast read-out times for moving pictures, and both provide the same movie specifications (4K/30p).

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the RX1R III has an electronic viewfinder (2360k dots), which can be very helpful when shooting in bright sunlight. In contrast, the fp relies on live view and the rear LCD for framing. That said, the fp can be equipped with an optional viewfinder – the EVF-11. The following table reports on some other key feature differences and similarities of the Sigma fp, the Sony RX1R III, 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.		Sigma fp	optional	n	3.2 / 2100	fixed	Y	1/8000s	12.0/s	n	n
2.		Sony RX1R III	2360	n	3.0 / 2360	fixed	Y	1/4000s	5.0/s	n	n
3.		Fujifilm X-Pro3	3690	n	3.0 / 1620	tilting	Y	1/8000s	8.0/s	n	n
4.		Leica Q3	5760	n	3.0 / 1840	tilting	Y	1/2000s	15.0/s	n	Y
5.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
6.		Nikon D780	optical	Y	3.2 / 2359	tilting	Y	1/8000s	12.0/s	n	n
7.		Panasonic S1	5760	Y	3.2 / 2100	full-flex	Y	1/8000s	9.0/s	n	Y
8.		Panasonic S1H	5760	Y	3.2 / 2330	swivel	Y	1/8000s	9.0/s	n	Y
9.		Panasonic S5	2360	n	3.0 / 1840	swivel	Y	1/8000s	7.0/s	n	Y
10.		Panasonic TS7	1170	n	3.0 / 1040	fixed	n	1/1300s	10.0/s	Y	Y
11.		Sigma fp L	optional	n	3.2 / 2100	fixed	Y	1/8000s	10.0/s	n	n
12.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
13.		Sony A7C	2360	n	3.0 / 922	swivel	Y	1/4000s	10.0/s	n	Y
14.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
15.		Sony A7S	2400	n	3.0 / 921	tilting	n	1/8000s	5.0/s	n	n
16.		Sony RX1R II	2360	n	3.0 / 1229	tilting	n	1/4000s	5.0/s	n	n
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 Sigma fp and the Sony RX1R III 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 fp and the RX1R III write their files to SDXC cards. Both cameras support UHS-II cards, which provide for Ultra High Speed data transfer of up to 312 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 Sigma fp and Sony Cyber-shot DSC-RX1R III 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.		Sigma fp	Y	stereo / mono	Y	-	micro	3.1	-	-	-
2.		Sony RX1R III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
3.		Fujifilm X-Pro3	Y	stereo / mono	Y	-	-	3.1	Y	-	Y
4.		Leica Q3	Y	stereo / mono	-	-	micro	3.1	Y	-	Y
5.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
6.		Nikon D780	Y	stereo / mono	Y	Y	mini	3.1	Y	-	Y
7.		Panasonic S1	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
8.		Panasonic S1H	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
9.		Panasonic S5	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
10.		Panasonic TS7	-	stereo / mono	-	-	micro	2.0	Y	-	-
11.		Sigma fp L	Y	stereo / mono	Y	Y	micro	3.2	Y	-	-
12.		Sony A7	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
13.		Sony A7C	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
14.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A7S	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony RX1R II	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-

It is notable that the RX1R III offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the fp does not provide wifi capability.

Both the fp and the RX1R III are recent models that are part of the current product line-up. The RX1R III replaced the earlier Sony RX1R II, while the fp does not have a direct predecessor. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Sigma and Sony websites.

Review summary

So what conclusions can be drawn? Which of the two cameras – the Sigma fp or the Sony RX1R III – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Sigma fp:

• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (12 vs 5 flaps/sec) to capture the decisive moment.
• More flexible: Accepts interchangeable lenses, so that lens characteristics can be altered.
• More heavily discounted: Has been available for much longer (launched in July 2019).

Arguments in favor of the Sony Cyber-shot DSC-RX1R III:

• More detail: Has more megapixels (60.2 vs 24MP), which boosts linear resolution by 58%.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• 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 (2360k vs 2100k dots).
• Ready to shoot: Has an integrated lens, whereas the fp necessitates an extra lens.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 3.1).
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• More modern: Reflects 6 years of technical progress since the fp launch.

If the count of individual advantages (bullet points above) is taken as a guide, the RX1R III is the clear winner of the contest (10 : 5 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. A professional wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports 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 Sigma fp and the Sony RX1R III place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best Prime Lens Compact Camera listings whether the two cameras rank among the cream of the crop.

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains incomplete and does no justice, for example, to the way the fp or the RX1R III 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 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	Street Price
1.		Sigma fp	4/5	..	4/5	..	4/5	4.5/5	Jul 2019	US$ 1 899	amazon.com
2.		Sony RX1R III	..	..	..	..	..	..	Jul 2025	US$ 5 099	amazon.com
3.		Fujifilm X-Pro3	4/5	+	4/5	85/100	4/5	..	Oct 2019	US$ 1 799	amazon.com
4.		Leica Q3	5/5	..	4.5/5	..	..	4.5/5	May 2023	US$ 5 999	amazon.com
5.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	US$ 7 449	ebay.com
6.		Nikon D780	5/5	..	5/5	87/100	4.5/5	4.5/5	Jan 2020	US$ 2 299	amazon.com
7.		Panasonic S1	4.5/5	+ +	4.5/5	88/100	4.5/5	4/5	Feb 2019	US$ 2 499	ebay.com
8.		Panasonic S1H	..	..	4/5	90/100	..	..	May 2019	US$ 3 999	amazon.com
9.		Panasonic S5	4.5/5	+ +	4.5/5	88/100	4.5/5	4.5/5	Sep 2020	US$ 1 999	amazon.com
10.		Panasonic TS7	..	+	..	..	..	3.5/5	May 2018	US$ 449	ebay.com
11.		Sigma fp L	4/5	..	4/5	..	4/5	4/5	Mar 2021	US$ 2 499	amazon.com
12.		Sony A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	US$ 1 699	ebay.com
13.		Sony A7C	3.5/5	..	3.5/5	86/100	4/5	4/5	Sep 2020	US$ 1 799	amazon.com
14.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	US$ 2 299	ebay.com
15.		Sony A7S	4/5	..	..	86/100	4.5/5	5/5	Apr 2014	US$ 2 499	ebay.com
16.		Sony RX1R II	5/5	..	..	82/100	..	4.5/5	Oct 2015	US$ 3 299	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, 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 comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

Check fp price at
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Check RX1R III price at
amazon.com

Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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