Sigma fp vs Sony A900

The Sigma fp and the Sony Alpha A900 are two digital cameras that were officially introduced, respectively, in July 2019 and September 2008. The fp is a mirrorless interchangeable lens camera, while the A900 is a DSLR. Both cameras are equipped with a full frame sensor. The Sigma has a resolution of 24 megapixels, whereas the Sony provides 24.4 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 A900
Mirrorless system camera		Digital single lens reflex
Leica L mount lenses		Sony A mount lenses
24 MP – Full Frame sensor		24.4 MP – Full Frame sensor
4K/30p Video		no Video
ISO 100-25,600 (6 - 102,400)		ISO 200-3,200 (100 - 6,400)
Viewfinder optional		Optical viewfinder
3.2" LCD – 2100k dots		3.0" LCD – 922k dots
Fixed touchscreen		Fixed screen (not touch-sensitive)
12 shutter flaps per second		5 shutter flaps per second
Lens stabilization only		In-body stabilization
Weathersealed body		Weathersealed body
280 shots per battery charge		880 shots per battery charge
113 x 70 x 45 mm, 422 g		156 x 117 x 82 mm, 895 g

Check fp price at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Sigma fp and the Sony Alpha A900? 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 A900. 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 size 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 A900 is considerably larger (131 percent) than the Sigma fp. Moreover, the A900 is substantially heavier (112 percent) than the 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 since they do not consider the interchangeable lenses that both of these cameras require. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

Concerning battery life, the fp gets 280 shots out of its Sigma BP-51 battery, while the A900 can take 880 images on a single charge of its Sony NP-FM500H power pack. The power pack in the fp can be charged via the USB port, so that it is not always necessary to take the battery charger along 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.		Sigma fp	113 mm	70 mm	45 mm	422 g	280	Y	Jul 2019	1,899	amazon.com
2.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
3.		Fujifilm X-Pro3	141 mm	83 mm	46 mm	497 g	440	Y	Oct 2019	1,799	amazon.com
4.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	7,450	ebay.com
5.		Nikon D780	144 mm	116 mm	76 mm	840 g	2260	Y	Jan 2020	2,299	amazon.com
6.		Panasonic S5	133 mm	98 mm	82 mm	714 g	440	Y	Sep 2020	1,999	amazon.com
7.		Panasonic S1	149 mm	110 mm	97 mm	1017 g	400	Y	Feb 2019	2,499	amazon.com
8.		Panasonic S1H	151 mm	114 mm	110 mm	1052 g	400	Y	May 2019	3,999	amazon.com
9.		Panasonic TS7	117 mm	76 mm	37 mm	319 g	300	Y	May 2018	449	ebay.com
10.		Sigma fp L	113 mm	70 mm	45 mm	427 g	240	Y	Mar 2021	2,499	amazon.com
11.		Sony A7C	124 mm	71 mm	60 mm	509 g	740	Y	Sep 2020	1,799	amazon.com
12.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
13.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
14.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
15.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	1,699	ebay.com
16.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
17.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	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 fp was launched at a markedly lower price (by 37 percent) than the A900, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

Sensor comparison

The size of the imaging sensor is a crucial determinant 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. 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 associated with larger, more expensive camera bodies and lenses.

Both cameras under consideration feature a full frame sensor, but their sensors differ slightly in size. 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.

With 24.4MP, the A900 offers a higher resolution than the fp (24MP), but the A900 has marginally smaller individual pixels (pixel pitch of 5.94μm versus 5.98μm for the fp). Yet, the fp is a much more recent model (by 10 years and 10 months) than the A900, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the fp has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

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 Alpha A900 are ISO 200 to ISO 3200, with the possibility to increase the ISO range to 100-6400.

In terms of underlying technology, the fp is build around a BSI-CMOS sensor, while the A900 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 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 A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
3.		Fujifilm X-Pro3	APS-C	26.0	6240	4160	4K/30p	24.1	13.6	1968	84
4.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
5.		Nikon D780	Full Frame	24.3	6048	4024	4K/30p	25.3	14.3	2877	95
6.		Panasonic S5	Full Frame	24.0	6000	4000	4K/60p	25.1	14.5	2697	94
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 TS7	1/2.3	20.2	5184	3888	4K/30p	20.6	12.1	1028	51
10.		Sigma fp L	Full Frame	60.2	9520	6328	4K/30p	25.3	14.4	3001	96
11.		Sony A7C	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3407	95
12.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
13.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
14.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
15.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90
16.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
17.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
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. The fp indeed provides movie recording capabilities, while the A900 does not. The highest resolution format that the fp can use is 4K/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A900 has an optical viewfinder, which can be very useful 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 table below summarizes some of the other core capabilities of the Sigma fp and Sony A900 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.		Sigma fp	optional	n	3.2 / 2100	fixed	Y	1/8000s	12.0/s	n	n
2.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
3.		Fujifilm X-Pro3	3690	n	3.0 / 1620	tilting	Y	1/8000s	8.0/s	n	n
4.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
5.		Nikon D780	optical	Y	3.2 / 2359	tilting	Y	1/8000s	12.0/s	n	n
6.		Panasonic S5	2360	n	3.0 / 1840	swivel	Y	1/8000s	7.0/s	n	Y
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 TS7	1170	n	3.0 / 1040	fixed	n	1/1300s	10.0/s	Y	Y
10.		Sigma fp L	optional	n	3.2 / 2100	fixed	Y	1/8000s	10.0/s	n	n
11.		Sony A7C	2360	n	3.0 / 922	swivel	Y	1/4000s	10.0/s	n	Y
12.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
13.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
14.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
15.		Sony A7	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	n
16.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
17.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The fp has a touchscreen, while the A900 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

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 fp 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 Sigma fp 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 fp writes its imaging data to SDXC cards, while the A900 uses Compact Flash or Memory Stick PRO Duo cards. The A900 features dual card slots, which can be very useful in case a memory card fails. In contrast, the fp only has one slot.

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 Alpha A900 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 A900	Y	- / -	-	-	mini	2.0	-	-	-
3.		Fujifilm X-Pro3	Y	stereo / mono	Y	-	-	3.1	Y	-	Y
4.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
5.		Nikon D780	Y	stereo / mono	Y	Y	mini	3.1	Y	-	Y
6.		Panasonic S5	Y	stereo / mono	Y	Y	micro	3.2	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 TS7	-	stereo / mono	-	-	micro	2.0	Y	-	-
10.		Sigma fp L	Y	stereo / mono	Y	Y	micro	3.2	Y	-	-
11.		Sony A7C	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
12.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
13.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
14.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A7	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
17.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-

Studio photographers will appreciate that the Sony A900 (unlike the fp) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

The fp is a recent model that features in the current product line-up of Sigma. In contrast, the A900 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the A900 was succeeded by the Sony A99. Further information on the features and operation of the fp and A900 can be found, respectively, in the Sigma fp Manual (free pdf) or the online Sony A900 Manual.

Review summary

So how do things add up? Is the Sigma fp better than the Sony A900 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Sigma fp:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Broader imaging potential: Can record not only still images but also 4K/30p movies.
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (2100k vs 922k dots).
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• Faster burst: Shoots at higher frequency (12 vs 5 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.
• More compact: Is smaller (113x70mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 473g or 53 percent) and hence easier to carry around.
• Easier travel charging: Can be conveniently charged via its USB port.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
• More affordable: Was introduced into a lower priced category (37 percent cheaper at launch).
• More modern: Reflects 10 years and 10 months of technical progress since the A900 launch.

Advantages of the Sony Alpha A900:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Longer lasting: Gets more shots (880 versus 280) out of a single battery charge.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• 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 2008).

If the number of relative strengths (bullet points above) is taken as a guide, the fp is the clear winner of the match-up (15 : 8 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 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 Sigma fp and the Sony A900 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best DSLR 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 A900 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 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.		Sigma fp	4/5	..	4/5	..	4/5	4.5/5	Jul 2019	1,899	amazon.com
2.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
3.		Fujifilm X-Pro3	4/5	+	4/5	85/100	4/5	..	Oct 2019	1,799	amazon.com
4.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	7,450	ebay.com
5.		Nikon D780	5/5	..	5/5	87/100	4.5/5	4.5/5	Jan 2020	2,299	amazon.com
6.		Panasonic S5	4.5/5	+ +	4.5/5	88/100	4.5/5	4.5/5	Sep 2020	1,999	amazon.com
7.		Panasonic S1	4.5/5	+ +	4.5/5	88/100	4.5/5	4/5	Feb 2019	2,499	amazon.com
8.		Panasonic S1H	..	..	4/5	90/100	..	..	May 2019	3,999	amazon.com
9.		Panasonic TS7	..	+	..	..	..	3.5/5	May 2018	449	ebay.com
10.		Sigma fp L	4/5	..	4/5	..	4/5	4/5	Mar 2021	2,499	amazon.com
11.		Sony A7C	3.5/5	..	3.5/5	86/100	4/5	4/5	Sep 2020	1,799	amazon.com
12.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
13.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
14.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
15.		Sony A7	5/5	+ +	..	80/100	5/5	5/5	Oct 2013	1,699	ebay.com
16.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
17.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	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. 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

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 use the search menu below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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