Olympus E-420 vs Sony A77

The Olympus E-420 and the Sony Alpha SLT-A77 are two digital cameras that were announced, respectively, in March 2008 and August 2011. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a Four Thirds (E-420) and an APS-C (A77) sensor. The Olympus has a resolution of 10 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

Olympus E-420		Sony A77
Digital single lens reflex		Digital single lens reflex
Four Thirds lenses		Sony A mount lenses
10 MP – Four Thirds sensor		24 MP – APS-C sensor
no Video		1080/60p Video
ISO 100-1,600		ISO 100-16,000 (50 - 25,600)
Optical viewfinder		Electronic viewfinder (2359k dots)
2.7" LCD – 215k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Fully flexible screen (no touchscreen)
3.5 shutter flaps per second		12 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
500 shots per battery charge		470 shots per battery charge
130 x 91 x 53 mm, 440 g		143 x 104 x 81 mm, 732 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus E-420 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 side-by-side display below illustrates the physical size and weight of the Olympus E-420 and the Sony A77. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. 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 A77 is notably larger (26 percent) than the Olympus E-420. Moreover, the A77 is substantially heavier (66 percent) than the E-420. It is noteworthy in this context that the A77 is splash and dust-proof, while the E-420 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 E-420 gets 500 shots out of its Olympus BLS-1 battery, while the A77 can take 470 images on a single charge of its Sony NP-FM500H power pack.

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.		Olympus E-420	130 mm	91 mm	53 mm	440 g	500	n	Mar 2008	599	ebay.com
2.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	ebay.com
3.		Nikon D3000	126 mm	97 mm	64 mm	536 g	500	n	Jul 2009	599	ebay.com
4.		Nikon D60	126 mm	94 mm	64 mm	522 g	500	n	Jan 2008	629	ebay.com
5.		Nikon D40X	124 mm	94 mm	64 mm	522 g	520	n	Mar 2007	729	ebay.com
6.		Olympus E-450	130 mm	91 mm	53 mm	440 g	500	n	Mar 2009	499	ebay.com
7.		Olympus E-600	130 mm	94 mm	60 mm	535 g	500	n	Aug 2009	449	ebay.com
8.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	699	ebay.com
9.		Olympus E-520	136 mm	92 mm	68 mm	535 g	750	n	May 2008	699	ebay.com
10.		Olympus E-410	130 mm	91 mm	53 mm	435 g	500	n	Mar 2007	699	ebay.com
11.		Olympus E-400	130 mm	91 mm	53 mm	435 g	500	n	Sep 2006	699	ebay.com
12.		Panasonic L10	135 mm	96 mm	78 mm	556 g	450	n	Aug 2007	599	ebay.com
13.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
14.		Sony A6500	120 mm	67 mm	53 mm	453 g	350	Y	Oct 2016	1,399	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

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. The E-420 was launched at a markedly lower price (by 57 percent) than the A77, 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. 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 sensor inside a digital camera is one of the key determinants of image quality. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and 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.

Of the two cameras under consideration, the Olympus E-420 features a Four Thirds sensor and the Sony A77 an APS-C sensor. The sensor area in the A77 is 63 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.5. The sensor in the E-420 has a native 4:3 aspect ratio, while the one in the A77 offers a 3:2 aspect.

With 24MP, the A77 offers a higher resolution than the E-420 (10MP), but the A77 has smaller individual pixels (pixel pitch of 3.91μm versus 4.74μm for the E-420). Yet, the A77 is a much more recent model (by 3 years and 5 months) than the E-420, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units.

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 Olympus E-420 are 18.2 x 13.7 inches or 46.3 x 34.7 cm for good quality, 14.6 x 10.9 inches or 37.1 x 27.8 cm for very good quality, and 12.2 x 9.1 inches or 30.9 x 23.2 cm for excellent quality prints.

The Olympus E-420 has a native sensitivity range from ISO 100 to ISO 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.

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.

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"). Of the two cameras under consideration, the A77 offers substantially better image quality than the E-420 (overall score 22 points higher). The advantage is based on 2.5 bits higher color depth, 2.8 EV in additional dynamic range, and 0.6 stops in additional low light sensitivity. 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.		Olympus E-420	Four Thirds	10.0	3648	2736	none	21.5	10.4	527	56
2.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
3.		Nikon D3000	APS-C	10.0	3872	2592	none	22.3	11.1	563	62
4.		Nikon D60	APS-C	10.0	3872	2592	none	22.5	11.4	562	65
5.		Nikon D40X	APS-C	10.0	3872	2592	none	22.4	11.4	516	63
6.		Olympus E-450	Four Thirds	10.0	3648	2736	none	21.5	10.5	512	56
7.		Olympus E-600	Four Thirds	12.2	4032	3024	none	21.5	10.3	541	55
8.		Olympus E-620	Four Thirds	12.2	4032	3024	none	21.3	10.3	536	55
9.		Olympus E-520	Four Thirds	10.0	3648	2736	none	21.4	10.4	548	55
10.		Olympus E-410	Four Thirds	10.0	3648	2736	none	21.1	10.0	494	51
11.		Olympus E-400	Four Thirds	10.0	3648	2736	none	21.0	10.6	127	53
12.		Panasonic L10	Four Thirds	10.0	3648	2736	none	21.3	10.8	429	55
13.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
14.		Sony A6500	APS-C	24.0	6000	4000	4K/30p	24.5	13.7	1405	85
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 cannot only take still pictures, but also record videos. The A77 indeed provides for movie recording, while the E-420 does not. The highest resolution format that the A77 can use is 1080/60p.

Feature comparison

Apart from 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 E-420 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 E-420 (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 0.46x), 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 Olympus E-420 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.		Olympus E-420	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
2.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
3.		Nikon D3000	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
4.		Nikon D60	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
5.		Nikon D40X	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
6.		Olympus E-450	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
7.		Olympus E-600	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
8.		Olympus E-620	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
9.		Olympus E-520	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	Y
10.		Olympus E-410	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	n
11.		Olympus E-400	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	n
12.		Panasonic L10	optical	n	2.5 / 207	swivel	n	1/4000s	3.0/s	Y	n
13.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
14.		Sony A6500	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	Y	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 E-420 is in-body image stabilization (IBIS). The A77 reduces the risk of handshake-induced blur with all attached lenses, while the E-420 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The E-420 writes its imaging data to Compact Flash or xD Picture cards, while the A77 uses SDXC or Memory Stick PRO Duo cards. The E-420 features dual card slots, which can be very useful in case a memory card fails. In contrast, the A77 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 Olympus E-420 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.		Olympus E-420	Y	- / -	-	-	-	2.0	-	-	-
2.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-
3.		Nikon D3000	Y	- / -	-	-	-	2.0	-	-	-
4.		Nikon D60	Y	- / -	-	-	-	2.0	-	-	-
5.		Nikon D40X	Y	- / -	-	-	-	2.0	-	-	-
6.		Olympus E-450	Y	- / -	-	-	-	2.0	-	-	-
7.		Olympus E-600	Y	- / -	-	-	-	2.0	-	-	-
8.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
9.		Olympus E-520	Y	- / -	-	-	-	2.0	-	-	-
10.		Olympus E-410	Y	- / -	-	-	-	2.0	-	-	-
11.		Olympus E-400	Y	- / -	-	-	-	2.0	-	-	-
12.		Panasonic L10	Y	- / -	-	-	-	2.0	-	-	-
13.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
14.		Sony A6500	Y	stereo / mono	Y	-	micro	2.0	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 E-420) 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 E-420 and the A77 have been discontinued, but can regularly be found used on ebay. The A77 was replaced by the Sony A77 II, while the E-420 does not have a direct successor. Further information on the features and operation of the E-420 and A77 can be found, respectively, in the Olympus E-420 Manual (free pdf) or the online Sony A77 Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Olympus E-420 or the Sony A77 – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Olympus E-420:

• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• More compact: Is smaller (130x91mm vs 143x104mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 292g or 40 percent) and hence easier to carry around.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More affordable: Was introduced into a lower priced category (57 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in March 2008).

Advantages of the Sony Alpha SLT-A77:

• More detail: Has more megapixels (24 vs 10MP), which boosts linear resolution by 58%.
• Better image quality: Scores substantially higher (22 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.5 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.8 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (0.6 stops ISO advantage).
• 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 0.46x).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.0" vs 2.7") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 215k 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 3.5 flaps/sec) to capture the decisive moment.
• 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.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More modern: Reflects 3 years and 5 months of technical progress since the E-420 launch.

If the number of relative strengths (bullet points above) is taken as a guide, the A77 is the clear winner of the contest (21 : 6 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 Olympus E-420 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 technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the E-420 and the A77 in practical situations. 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 where reviews by experts come in. 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.		Olympus E-420	..	85/100	..	+ +	4/5	4.5/5	Mar 2008	599	ebay.com
2.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	ebay.com
3.		Nikon D3000	..	+	..	72/100	4/5	4.5/5	Jul 2009	599	ebay.com
4.		Nikon D60	..	80/100	..	+ +	4/5	4.5/5	Jan 2008	629	ebay.com
5.		Nikon D40X	..	79/100	..	+ +	4/5	4/5	Mar 2007	729	ebay.com
6.		Olympus E-450	..	..	..	..	4/5	4/5	Mar 2009	499	ebay.com
7.		Olympus E-600	..	..	..	..	..	4.5/5	Aug 2009	449	ebay.com
8.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	699	ebay.com
9.		Olympus E-520	..	87/100	..	+ +	4.5/5	4.5/5	May 2008	699	ebay.com
10.		Olympus E-410	..	86/100	..	+ +	4/5	4.5/5	Mar 2007	699	ebay.com
11.		Olympus E-400	..	85/100	..	..	4/5	4/5	Sep 2006	699	ebay.com
12.		Panasonic L10	..	85/100	..	+	3.5/5	4/5	Aug 2007	599	ebay.com
13.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
14.		Sony A6500	5/5	+ +	3.5/5	85/100	4.5/5	4.5/5	Oct 2016	1,399	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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. 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 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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