Sony A99 II vs A5100

The Sony Alpha ALT-A99 II and the Sony Alpha A5100 are two digital cameras that were announced, respectively, in September 2016 and August 2014. The A99 II is a DSLR, while the A5100 is a mirrorless interchangeable lens camera. The cameras are based on a full frame (A99 II) and an APS-C (A5100) sensor. The A99 II has a resolution of 42.2 megapixels, whereas the A5100 provides 24 MP.

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

Headline Specifications

Sony A99 II		Sony A5100
Digital single lens reflex		Mirrorless system camera
Sony A mount lenses		Sony E mount lenses
42.2 MP – Full Frame sensor		24 MP – APS-C sensor
4K/30p Video		1080/60p Video
ISO 100-25,600		ISO 100-25,600
Electronic viewfinder (2400k dots)		No viewfinder, LCD framing
3.0" LCD – 1229k dots		3.0" LCD – 922k dots
Fully flexible screen (no touchscreen)		Tilting touchscreen
12 shutter flaps per second		6 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		not weather sealed
490 shots per battery charge		400 shots per battery charge
143 x 104 x 76 mm, 849 g		110 x 63 x 36 mm, 283 g

Check A99 II offers at
ebay.com
Check A5100 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha ALT-A99 II and the Sony Alpha A5100? 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 A99 II and the Sony A5100 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 dimensions are rounded to the nearest millimeter.

The A5100 can be obtained in two different colors (black, white), while the A99 II 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 Sony A5100 is considerably smaller (53 percent) than the Sony A99 II. Moreover, the A5100 is substantially lighter (67 percent) than the A99 II. It is worth mentioning in this context that the A99 II is splash and dust resistant, while the A5100 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. 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 A99 II gets 490 shots out of its Sony NP-FM500H battery, while the A5100 can take 400 images on a single charge of its Sony NP-FW50 power pack. The power pack in the A5100 can be charged via the USB port, 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. In case you want to display and compare another camera duo, you can use the CAM-parator app to select your camera combination among a large number of options.

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 A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
2.		Sony A5100	110 mm	63 mm	36 mm	283 g	400	n	Aug 2014	549	ebay.com
3.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
4.		Nikon D850	146 mm	124 mm	79 mm	1005 g	1840	Y	Jul 2017	3,299	amazon.com
5.		Pentax K-1	137 mm	110 mm	86 mm	1010 g	760	Y	Feb 2016	1,799	ebay.com
6.		Sony A7R II	127 mm	96 mm	60 mm	625 g	290	Y	Jun 2015	3,199	ebay.com
7.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	3,199	ebay.com
8.		Sony A7R IIIA	127 mm	96 mm	74 mm	650 g	650	Y	Apr 2021	3,199	amazon.com
9.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999	ebay.com
10.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	ebay.com
11.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	ebay.com
12.		Sony A900	156 mm	117 mm	82 mm	895 g	880	Y	Sep 2008	2,999	ebay.com
13.		Sony A3000	128 mm	91 mm	85 mm	411 g	470	n	Aug 2013	329	ebay.com
14.		Sony A5000	110 mm	63 mm	36 mm	269 g	420	n	Jan 2014	449	ebay.com
15.		Sony A6000	120 mm	67 mm	45 mm	344 g	360	n	Feb 2014	599	ebay.com
16.		Sony NEX-3	117 mm	62 mm	33 mm	297 g	330	n	May 2010	599	ebay.com
17.		Sony NEX-3N	110 mm	62 mm	35 mm	269 g	480	n	Feb 2013	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 A5100 was launched at a markedly lower price (by 83 percent) than the A99 II, which puts it into a different market segment. 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.

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. 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 more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A99 II features a full frame sensor and the Sony A5100 an APS-C sensor. The sensor area in the A5100 is 57 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 42.2MP, the A99 II offers a higher resolution than the A5100 (24MP), but the A99 II nevertheless has larger individual pixels (pixel pitch of 4.52μm versus 3.91μm for the A5100) due to its larger sensor. Moreover, the A99 II is a much more recent model (by 2 years and 1 month) 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 A99 II has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Sony A99 II implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A99 II for good quality output (200 dots per inch) amounts to 39.8 x 26.5 inches or 101 x 67.4 cm, for very good quality (250 dpi) 31.8 x 21.2 inches or 80.8 x 53.9 cm, and for excellent quality (300 dpi) 26.5 x 17.7 inches or 67.3 x 44.9 cm. The corresponding values for the Sony A5100 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 Sony Alpha ALT-A99 II has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 50-25600. The corresponding ISO settings for the Sony Alpha A5100 are ISO 100 to ISO 25600 (no boost).

In terms of underlying technology, the A99 II is build around a BSI-CMOS sensor, while the A5100 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.

For many cameras, data on sensor performance has been reported by DXO Mark. 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"). Of the two cameras under review, the A99 II provides substantially higher image quality than the A5100, with an overall score that is 12 points higher. This advantage is based on 1.6 bits higher color depth, 0.7 EV in additional dynamic range, and 0.8 stops in additional low light sensitivity. 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 A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
2.		Sony A5100	APS-C	24.0	6000	4000	1080/60p	23.8	12.7	1347	80
3.		Canon 5DS R	Full Frame	50.3	8688	5792	1080/30p	24.6	12.4	2308	86
4.		Nikon D850	Full Frame	45.4	8256	5504	4K/30p	26.4	14.8	2660	100
5.		Pentax K-1	Full Frame	36.2	7360	4912	1080/60i	25.4	14.6	3280	96
6.		Sony A7R II	Full Frame	42.2	7952	5304	4K/30p	26.0	13.9	3434	98
7.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
8.		Sony A7R IIIA	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
9.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85
10.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
11.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
12.		Sony A900	Full Frame	24.4	6048	4032	none	23.7	12.3	1431	79
13.		Sony A3000	APS-C	19.8	5456	3632	1080/60i	23.7	12.8	1068	78
14.		Sony A5000	APS-C	19.8	5456	3632	1080/60i	23.8	13.0	1089	79
15.		Sony A6000	APS-C	24.0	6000	4000	1080/60p	24.1	13.1	1347	82
16.		Sony NEX-3	APS-C	14.0	4592	3056	720/30p	22.1	12.0	830	68
17.		Sony NEX-3N	APS-C	16.0	4912	3264	1080/60i	22.8	12.5	1067	74

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, but the A99 II provides a higher video resolution than the A5100. It can shoot video footage at 4K/30p, while the A5100 is limited to 1080/60p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A99 II has an electronic viewfinder (2400k 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 adjacent table lists some of the other core features of the Sony A99 II and Sony A5100 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.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
2.		Sony A5100	none	n	3.0 / 922	tilting	Y	1/4000s	6.0/s	Y	n
3.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
4.		Nikon D850	optical	Y	3.2 / 2359	tilting	Y	1/8000s	9.0/s	n	n
5.		Pentax K-1	optical	Y	3.2 / 1037	full-flex	n	1/8000s	4.4/s	n	Y
6.		Sony A7R II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
7.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
8.		Sony A7R IIIA	3686	n	3.0 / 2340	tilting	Y	1/8000s	10.0/s	n	Y
9.		Sony A7S II	2400	n	3.0 / 1229	tilting	n	1/8000s	5.0/s	n	Y
10.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
11.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
12.		Sony A900	optical	Y	3.0 / 922	fixed	n	1/8000s	5.0/s	n	Y
13.		Sony A3000	202	n	3.0 / 230	fixed	n	1/4000s	2.5/s	Y	n
14.		Sony A5000	none	n	3.0 / 461	tilting	n	1/4000s	3.5/s	Y	n
15.		Sony A6000	1440	n	3.0 / 922	tilting	n	1/4000s	11.0/s	Y	n
16.		Sony NEX-3	optional	n	3.0 / 920	tilting	n	1/4000s	7.0/s	n	n
17.		Sony NEX-3N	optional	n	3.0 / 460	tilting	n	1/4000s	4.0/s	Y	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the A99 II, but is missing on the A5100 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

Concerning the storage of imaging data, both the A99 II and the A5100 write their files to SDXC or Memory Stick PRO Duo cards. The A99 II features dual card slots, which can be very useful in case a memory card fails. In contrast, the A5100 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 Sony Alpha ALT-A99 II and Sony Alpha A5100 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 A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
2.		Sony A5100	-	stereo / mono	-	-	micro	2.0	Y	Y	-
3.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
4.		Nikon D850	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
5.		Pentax K-1	Y	stereo / mono	Y	Y	micro	2.0	Y	-	-
6.		Sony A7R II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
7.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
8.		Sony A7R IIIA	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y
9.		Sony A7S II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
10.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
11.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-
12.		Sony A900	Y	- / -	-	-	mini	2.0	-	-	-
13.		Sony A3000	Y	stereo / mono	-	-	mini	2.0	-	-	-
14.		Sony A5000	-	stereo / mono	-	-	micro	2.0	Y	Y	-
15.		Sony A6000	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
16.		Sony NEX-3	Y	stereo / mono	-	-	mini	2.0	-	-	-
17.		Sony NEX-3N	-	stereo / mono	-	-	micro	2.0	-	-	-

It is notable that the A99 II has a hotshoe, while the A5100 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.

Studio photographers will appreciate that the Sony A99 II (unlike the A5100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the A99 II and the A5100 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. Further information on the features and operation of the A99 II and A5100 can be found, respectively, in the Sony A99 II Manual (free pdf) or the online Sony A5100 Manual.

Review summary

So how do things add up? Is there a clear favorite between the Sony A99 II and the Sony A5100? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Sony Alpha ALT-A99 II:

• More detail: Offers more megapixels (42.2 vs 24MP) with a 33% higher linear resolution.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (12 points) in the DXO overall assessment.
• Richer colors: Generates images with noticeably better colors (1.6 bits more color depth).
• More dynamic range: Captures a larger spectrum of light and dark details (0.7 EV of extra DR).
• Better low-light sensitivity: Requires less light for good images (0.8 stops ISO advantage).
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• 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.
• Easier setting verification: Features an LCD display on top to control shooting parameters.
• More detailed LCD: Has a higher resolution rear screen (1229k vs 922k dots).
• More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (12 vs 6 flaps/sec) to capture the decisive moment.
• Longer lasting: Can take more shots (490 versus 400) 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.
• 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.
• 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 modern: Reflects 2 years and 1 month of technical progress since the A5100 launch.

Arguments in favor of the Sony Alpha A5100:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• More compact: Is smaller (110x63mm vs 143x104mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 566g or 67 percent) and is thus easier to take along.
• Easier travel charging: Can be conveniently charged via its USB port.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• More affordable: Was introduced into a lower priced category (83 percent cheaper at launch).
• More heavily discounted: Has been around for much longer (launched in August 2014).

If the number of relative strengths (bullet points above) is taken as a guide, the A99 II is the clear winner of the match-up (23 : 9 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 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 Sony A99 II and the Sony A5100 place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens 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 A99 II and the A5100 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 hands-on reviews by experts 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.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
2.		Sony A5100	4.5/5	+	..	..	4.5/5	5/5	Aug 2014	549	ebay.com
3.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	3,699	ebay.com
4.		Nikon D850	4.5/5	+ +	5/5	89/100	4.5/5	5/5	Jul 2017	3,299	amazon.com
5.		Pentax K-1	5/5	..	..	84/100	5/5	5/5	Feb 2016	1,799	ebay.com
6.		Sony A7R II	5/5	+ +	5/5	90/100	5/5	5/5	Jun 2015	3,199	ebay.com
7.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	3,199	ebay.com
8.		Sony A7R IIIA	..	+ +	4/5	90/100	4.5/5	5/5	Apr 2021	3,199	amazon.com
9.		Sony A7S II	5/5	+	..	..	4.5/5	5/5	Sep 2015	2,999	ebay.com
10.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	ebay.com
11.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
12.		Sony A900	..	+ +	..	+ +	4.5/5	5/5	Sep 2008	2,999	ebay.com
13.		Sony A3000	3/5	+	..	..	4/5	4/5	Aug 2013	329	ebay.com
14.		Sony A5000	3/5	+	..	..	4.5/5	4.5/5	Jan 2014	449	ebay.com
15.		Sony A6000	5/5	+	4.5/5	80/100	4.5/5	5/5	Feb 2014	599	ebay.com
16.		Sony NEX-3	..	..	..	70/100	4.5/5	4/5	May 2010	599	ebay.com
17.		Sony NEX-3N	3/5	..	..	..	4.5/5	4.5/5	Feb 2013	499	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. 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. 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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