Nikon D100 vs Sony A77

The Nikon D100 and the Sony Alpha SLT-A77 are two enthusiast cameras that were revealed to the public, respectively, in February 2002 and August 2011. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Nikon has a resolution of 6 megapixels, whereas the Sony provides 24 MP.

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

Headline Specifications

Nikon D100		Sony A77
Digital single lens reflex		Digital single lens reflex
Nikon F mount lenses		Sony A mount lenses
6 MP – APS-C sensor		24 MP – APS-C sensor
no Video		1080/60p Video
ISO 200-800 (200 - 1,600)		ISO 100-16,000 (50 - 25,600)
Optical viewfinder		Electronic viewfinder (2359k dots)
1.8" LCD – 118k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Fully flexible screen (no touchscreen)
3 shutter flaps per second		12 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
370 shots per battery charge		470 shots per battery charge
144 x 116 x 81 mm, 780 g		143 x 104 x 81 mm, 732 g

Check D100 offers at
ebay.com
Check A77 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D100 and the Sony Alpha SLT-A77? 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 physical size and weight of the Nikon D100 and the Sony A77 are illustrated 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.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A77 is notably smaller (11 percent) than the Nikon D100. Moreover, the A77 is markedly lighter (6 percent) than the D100. It is noteworthy in this context that the A77 is splash and dust-proof, while the D100 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 D100 gets 370 shots out of its Nikon EN-EL3 battery, while the A77 can take 470 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. 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.		Nikon D100	144 mm	116 mm	81 mm	780 g	370	n	Feb 2002	1,999	ebay.com
2.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
3.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	1,999	ebay.com
4.		Nikon D500	147 mm	115 mm	81 mm	860 g	1240	Y	Jan 2016	1,999	ebay.com
5.		Nikon D300S	147 mm	115 mm	81 mm	938 g	950	Y	Jul 2009	1,799	ebay.com
6.		Nikon D90	132 mm	103 mm	77 mm	703 g	850	n	Aug 2008	1,299	ebay.com
7.		Nikon D300	147 mm	114 mm	74 mm	925 g	1000	Y	Aug 2007	1,799	ebay.com
8.		Nikon D40	124 mm	94 mm	64 mm	522 g	470	n	Nov 2006	499	ebay.com
9.		Nikon D80	132 mm	103 mm	77 mm	668 g	600	n	Aug 2006	999	ebay.com
10.		Nikon D70s	140 mm	111 mm	78 mm	679 g	500	n	Apr 2005	899	ebay.com
11.		Nikon D200	147 mm	113 mm	74 mm	920 g	400	Y	Nov 2005	1,699	ebay.com
12.		Nikon D70	140 mm	111 mm	78 mm	679 g	400	n	Jan 2004	999	ebay.com
13.		Panasonic GH5	139 mm	98 mm	87 mm	725 g	410	Y	Jan 2017	1,999	ebay.com
14.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499	ebay.com
15.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999	ebay.com
16.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	1,199	ebay.com
17.		Sony A99	147 mm	111 mm	78 mm	812 g	500	Y	Sep 2012	2,799	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

Any camera decision will obviously take relative prices into account. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The A77 was launched at a markedly lower price (by 30 percent) than the D100, 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.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the A77 is 1 percent smaller. They nevertheless have the same format factor of 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Despite having a slightly smaller sensor, the A77 offers a higher resolution of 24 megapixels, compared with 6 MP of the D100. 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 3.91μm versus 7.85μm for the D100). However, it should be noted that the A77 is much more recent (by 9 years and 6 months) than the D100, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently.

The resolution advantage of the Sony A77 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A77 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 Nikon D100 are 15 x 10 inches or 38.2 x 25.4 cm for good quality, 12 x 8 inches or 30.6 x 20.3 cm for very good quality, and 10 x 6.7 inches or 25.5 x 16.9 cm for excellent quality prints.

The Nikon D100 has a native sensitivity range from ISO 200 to ISO 800, which can be extended to ISO 200-1600. The corresponding ISO settings for the Sony Alpha SLT-A77 are ISO 100 to ISO 16000, with the possibility to increase the ISO range to 50-25600.

In terms of underlying technology, the D100 is build around a CCD sensor, while the A77 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"). 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.		Nikon D100	APS-C	6.0	3008	2000	none	20.4	9.9	394	48
2.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
3.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
4.		Nikon D500	APS-C	20.7	5568	3712	4K/30p	24.0	14.0	1324	83
5.		Nikon D300S	APS-C	12.2	4288	2848	720/24p	22.5	12.2	787	70
6.		Nikon D90	APS-C	12.2	4288	2848	720/24p	22.7	12.5	977	73
7.		Nikon D300	APS-C	12.2	4288	2848	none	22.1	12.0	679	67
8.		Nikon D40	APS-C	6.0	3008	2000	none	21.0	11.0	561	56
9.		Nikon D80	APS-C	10.0	3872	2592	none	22.1	11.2	524	61
10.		Nikon D70s	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
11.		Nikon D200	APS-C	10.0	3872	2592	none	22.3	11.5	583	64
12.		Nikon D70	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
13.		Panasonic GH5	Four Thirds	20.2	5184	3888	4K/60p	23.9	13.0	807	77
14.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
15.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
16.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
17.		Sony A99	Full Frame	24.0	6000	4000	1080/60p	25.0	14.0	1555	89
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 can also record movies. The A77 indeed provides for movie recording, while the D100 does not. The highest resolution format that the A77 can use is 1080/60p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A77 has an electronic viewfinder (2359k dots), while the D100 has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The viewfinder in the A77 offers a wider field of view (100%) than the one in the D100 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the A77 has a higher magnification (0.73x vs 0.53x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Nikon D100 and Sony A77 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.		Nikon D100	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
2.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
3.		Canon 10D	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
4.		Nikon D500	optical	Y	3.2 / 2359	tilting	Y	1/8000s	10.0/s	n	n
5.		Nikon D300S	optical	Y	3.0 / 920	fixed	n	1/8000s	7.0/s	Y	n
6.		Nikon D90	optical	Y	3.0 / 920	fixed	n	1/4000s	4.5/s	Y	n
7.		Nikon D300	optical	Y	3.0 / 922	fixed	n	1/8000s	6.0/s	Y	n
8.		Nikon D40	optical	n	2.5 / 230	fixed	n	1/4000s	2.5/s	Y	n
9.		Nikon D80	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
10.		Nikon D70s	optical	n	2.0 / 130	fixed	n	1/8000s	3.0/s	Y	n
11.		Nikon D200	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
12.		Nikon D70	optical	n	1.8 / 130	fixed	n	1/8000s	3.0/s	Y	n
13.		Panasonic GH5	3680	n	3.2 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
14.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
15.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
16.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	Y	Y
17.		Sony A99	2359	Y	3.0 / 1229	full-flex	n	1/8000s	6.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the A77 and the D100 is in-body image stabilization (IBIS). The A77 reduces the risk of handshake-induced blur with all attached lenses, while the D100 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The D100 writes its imaging data to Compact Flash cards, while the A77 uses SDXC or Memory Stick PRO Duo cards.

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 Nikon D100 and Sony Alpha SLT-A77 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.		Nikon D100	Y	- / -	-	-	-	1.1	-	-	-
2.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
3.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
4.		Nikon D500	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
5.		Nikon D300S	Y	stereo / mono	Y	-	mini	2.0	-	-	-
6.		Nikon D90	Y	mono / mono	-	-	mini	2.0	-	-	-
7.		Nikon D300	Y	- / -	-	-	mini	2.0	-	-	-
8.		Nikon D40	Y	- / -	-	-	-	2.0	-	-	-
9.		Nikon D80	Y	- / -	-	-	-	2.0	-	-	-
10.		Nikon D70s	Y	- / -	-	-	-	2.0	-	-	-
11.		Nikon D200	Y	- / -	-	-	-	2.0	-	-	-
12.		Nikon D70	Y	- / -	-	-	-	1.0	-	-	-
13.		Panasonic GH5	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
14.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
15.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
16.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
17.		Sony A99	Y	stereo / mono	Y	Y	mini	2.0	-	-	-

Studio photographers will appreciate that the Sony A77 (unlike the D100) 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 A77 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

Both the D100 and the A77 have been discontinued, but can regularly be found used on ebay. The D100 was replaced by the Nikon D200, while the A77 was followed by the Sony A77 II. Further information on the features and operation of the D100 and A77 can be found, respectively, in the Nikon D100 Manual (free pdf) or the online Sony A77 Manual.

Review summary

So what conclusions can be drawn? Is the Nikon D100 better than the Sony A77 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Nikon D100:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• More heavily discounted: Has been available for much longer (launched in February 2002).

Arguments in favor of the Sony Alpha SLT-A77:

• More detail: Has more megapixels (24 vs 6MP), which boosts linear resolution by 100%.
• Broader imaging potential: Can capture not only stills but also 1080/60p video.
• More framing info: Has an electronic viewfinder that displays shooting data.
• More complete view: Has a viewfinder with a larger field of view (100% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.73x vs 0.53x).
• Larger screen: Has a bigger rear LCD (3.0" vs 1.8") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 118k dots).
• More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (12 vs 3 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (143x104mm vs 144x116mm) and will fit more readily into a bag.
• Longer lasting: Gets more shots (470 versus 370) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• Faster data transfer: Supports a more advanced USB protocol (2.0 vs 1.1).
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More affordable: Was introduced into a lower priced category (30 percent cheaper at launch).
• More modern: Reflects 9 years and 6 months of technical progress since the D100 launch.

If the count of relative strengths (bullet points above) is taken as a measure, the A77 is the clear winner of the contest (20 : 2 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 Nikon D100 and the Sony A77 place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing 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 D100 or the A77 perform in practice. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable.

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 (USD)	Street Price
1.		Nikon D100	..	..	..	+ +	o	..	Feb 2002	1,999	ebay.com
2.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
3.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	1,999	ebay.com
4.		Nikon D500	5/5	+ +	4.7/5	91/100	4.5/5	5/5	Jan 2016	1,999	ebay.com
5.		Nikon D300S	5/5	+ +	..	82/100	4/5	4.5/5	Jul 2009	1,799	ebay.com
6.		Nikon D90	..	+ +	..	+ +	4/5	4.5/5	Aug 2008	1,299	ebay.com
7.		Nikon D300	..	+ +	..	+ +	5/5	4.5/5	Aug 2007	1,799	ebay.com
8.		Nikon D40	..	81/100	..	+ +	o	4.5/5	Nov 2006	499	ebay.com
9.		Nikon D80	..	+	..	+ +	o	4.5/5	Aug 2006	999	ebay.com
10.		Nikon D70s	..	..	..	..	..	5/5	Apr 2005	899	ebay.com
11.		Nikon D200	..	+ +	..	+ +	o	..	Nov 2005	1,699	ebay.com
12.		Nikon D70	..	..	..	+ +	..	..	Jan 2004	999	ebay.com
13.		Panasonic GH5	4.5/5	+ +	..	85/100	4.5/5	5/5	Jan 2017	1,999	ebay.com
14.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	4,499	ebay.com
15.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	1,999	ebay.com
16.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	1,199	ebay.com
17.		Sony A99	5/5	..	..	84/100	4.5/5	4.5/5	Sep 2012	2,799	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. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Check D100 offers at
ebay.com
Check A77 offers at
ebay.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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.

~

Check D100 offers at
ebay.com
Check A77 offers at
ebay.com

Did you notice an error on this page? If so, please get in touch, so that we can correct the information.