Olympus E-400 vs Pentax K-S2

The Olympus E-400 and the Pentax K-S2 are two digital cameras that were revealed to the public, respectively, in September 2006 and February 2015. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a Four Thirds (E-400) and an APS-C (K-S2) sensor. The Olympus has a resolution of 10 megapixels, whereas the Pentax provides 20 MP.

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

Headline Specifications

Olympus E-400		Pentax K-S2
Digital single lens reflex		Digital single lens reflex
Four Thirds lenses		Pentax K mount lenses
10 MP – Four Thirds sensor		20 MP – APS-C sensor
no Video		1080/30p Video
ISO 100-1,600		ISO 100-51,200
Optical viewfinder		Optical viewfinder
2.5" LCD – 215k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Swivel screen (not touch-sensitive)
3 shutter flaps per second		5.4 shutter flaps per second
Lens stabilization only		In-body stabilization
not weather sealed		Weathersealed body
500 shots per battery charge		410 shots per battery charge
130 x 91 x 53 mm, 435 g		123 x 91 x 73 mm, 678 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus E-400 and the Pentax K-S2? 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 Olympus E-400 and the Pentax K-S2 are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth dimensions are rounded to the nearest millimeter.

The K-S2 can be obtained in six different colors (black, grey, pink, orange, green, white), while the E-400 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 Pentax K-S2 is notably smaller (5 percent) than the Olympus E-400. However, the K-S2 is substantially heavier (56 percent) than the E-400. It is noteworthy in this context that the K-S2 is splash and dust-proof, while the E-400 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-400 gets 500 shots out of its Olympus BLS-1 battery, while the K-S2 can take 410 images on a single charge of its Pentax D-LI109 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price	Street Price
1.		Olympus E-400	130 mm	91 mm	53 mm	435 g	500	n	Sep 2006	US$ 699	ebay.com
2.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	US$ 749	ebay.com
3.		Nikon D40X	124 mm	94 mm	64 mm	522 g	520	n	Mar 2007	US$ 729	ebay.com
4.		Olympus E-410	130 mm	91 mm	53 mm	435 g	500	n	Mar 2007	US$ 699	ebay.com
5.		Olympus E-420	130 mm	91 mm	53 mm	440 g	500	n	Mar 2008	US$ 599	ebay.com
6.		Olympus E-450	130 mm	91 mm	53 mm	440 g	500	n	Mar 2009	US$ 499	ebay.com
7.		Olympus E-500	130 mm	95 mm	66 mm	479 g	750	n	Sep 2005	US$ 599	ebay.com
8.		Olympus E-510	136 mm	92 mm	68 mm	538 g	750	n	Mar 2007	US$ 799	ebay.com
9.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	US$ 699	ebay.com
10.		Olympus Stylus 1	116 mm	87 mm	57 mm	402 g	410	n	Oct 2013	US$ 699	ebay.com
11.		Olympus Stylus 1s	116 mm	87 mm	57 mm	402 g	450	n	Apr 2015	US$ 699	ebay.com
12.		Panasonic L10	135 mm	96 mm	78 mm	556 g	450	n	Aug 2007	US$ 599	ebay.com
13.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	US$ 1 299	ebay.com
14.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	US$ 1 099	ebay.com
15.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	US$ 649	ebay.com
16.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	US$ 1 099	ebay.com
17.		Pentax K-S1	121 mm	93 mm	70 mm	558 g	410	n	Aug 2014	US$ 749	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
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Any camera decision will naturally be influenced heavily by the price. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The E-400 was somewhat cheaper (by 7 percent) than the K-S2 at launch, but both cameras fall into the same price category. 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. 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Olympus E-400 features a Four Thirds sensor and the Pentax K-S2 an APS-C sensor. The sensor area in the K-S2 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-400 has a native 4:3 aspect ratio, while the one in the K-S2 offers a 3:2 aspect.

With 20MP, the K-S2 offers a higher resolution than the E-400 (10MP), but the K-S2 has smaller individual pixels (pixel pitch of 4.28μm versus 4.74μm for the E-400). Yet, the K-S2 is a much more recent model (by 8 years and 4 months) than the E-400, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the K-S2 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax K-S2 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-S2 for good quality output (200 dots per inch) amounts to 27.4 x 18.2 inches or 69.5 x 46.3 cm, for very good quality (250 dpi) 21.9 x 14.6 inches or 55.6 x 37.1 cm, and for excellent quality (300 dpi) 18.2 x 12.2 inches or 46.3 x 30.9 cm. The corresponding values for the Olympus E-400 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-400 has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Pentax K-S2 are ISO 100 to ISO 51200 (no boost).

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"). 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.		Olympus E-400	Four Thirds	10.0	3648	2736	none	21.0	10.6	127	53
2.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
3.		Nikon D40X	APS-C	10.0	3872	2592	none	22.4	11.4	516	63
4.		Olympus E-410	Four Thirds	10.0	3648	2736	none	21.1	10.0	494	51
5.		Olympus E-420	Four Thirds	10.0	3648	2736	none	21.5	10.4	527	56
6.		Olympus E-450	Four Thirds	10.0	3648	2736	none	21.5	10.5	512	56
7.		Olympus E-500	Four Thirds	8.0	3264	2448	none	20.7	10.3	45	51
8.		Olympus E-510	Four Thirds	10.0	3648	2736	none	21.2	10.0	442	52
9.		Olympus E-620	Four Thirds	12.2	4032	3024	none	21.3	10.3	536	55
10.		Olympus Stylus 1	1/1.7	11.8	3968	2976	1080/30p	20.7	11.6	179	51
11.		Olympus Stylus 1s	1/1.7	11.8	3968	2976	1080/30p	20.2	11.3	-111	47
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.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
15.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
16.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
17.		Pentax K-S1	APS-C	20.0	5472	3648	1080/30p	23.5	13.0	1061	78
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 K-S2 indeed provides for movie recording, while the E-400 does not. The highest resolution format that the K-S2 can use is 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The E-400 and the K-S2 are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The viewfinder in the K-S2 offers a wider field of view (100%) than the one in the E-400 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the K-S2 has a higher magnification (0.63x 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-400 and Pentax K-S2 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-400	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	n
2.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
3.		Nikon D40X	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
4.		Olympus E-410	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	n
5.		Olympus E-420	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
6.		Olympus E-450	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
7.		Olympus E-500	optical	n	2.5 / 215	fixed	n	1/4000s	2.5/s	Y	n
8.		Olympus E-510	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	Y
9.		Olympus E-620	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
10.		Olympus Stylus 1	1440	n	3.0 / 1040	tilting	Y	1/2000s	7.0/s	Y	Y
11.		Olympus Stylus 1s	1440	n	3.0 / 1040	tilting	Y	1/2000s	7.0/s	Y	Y
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.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
15.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
16.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
17.		Pentax K-S1	optical	n	3.0 / 921	fixed	n	1/6000s	5.4/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the K-S2 and the E-400 is in-body image stabilization (IBIS). The K-S2 reduces the risk of handshake-induced blur with all attached lenses, while the E-400 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The Pentax K-S2 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 E-400 writes its imaging data to Compact Flash or xD Picture cards, while the K-S2 uses SDXC cards. The E-400 features dual card slots, which can be very useful in case a memory card fails. In contrast, the K-S2 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-400 and Pentax K-S2 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-400	Y	- / -	-	-	-	2.0	-	-	-
2.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
3.		Nikon D40X	Y	- / -	-	-	-	2.0	-	-	-
4.		Olympus E-410	Y	- / -	-	-	-	2.0	-	-	-
5.		Olympus E-420	Y	- / -	-	-	-	2.0	-	-	-
6.		Olympus E-450	Y	- / -	-	-	-	2.0	-	-	-
7.		Olympus E-500	Y	- / -	-	-	-	2.0	-	-	-
8.		Olympus E-510	Y	- / -	-	-	-	2.0	-	-	-
9.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
10.		Olympus Stylus 1	Y	stereo / mono	-	-	micro	2.0	Y	-	-
11.		Olympus Stylus 1s	Y	stereo / mono	-	-	micro	2.0	Y	-	-
12.		Panasonic L10	Y	- / -	-	-	-	2.0	-	-	-
13.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
14.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
16.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
17.		Pentax K-S1	Y	stereo / mono	-	-	micro	2.0	-	-	-

It is notable that the K-S2 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the E-400 does not provide wifi capability.

Both the E-400 and the K-S2 have been discontinued, but can regularly be found used on ebay. The E-400 was replaced by the Olympus E-410, while the K-S2 does not have a direct successor. Further information on the features and operation of the E-400 and K-S2 can be found, respectively, in the Olympus E-400 Manual (free pdf) or the online Pentax K-S2 Manual.

Review summary

So how do things add up? Is there a clear favorite between the Olympus E-400 and the Pentax K-S2? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Olympus E-400:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Less heavy: Is lighter (by 243g or 36 percent) and hence easier to carry around.
• Longer lasting: Can take more shots (500 versus 410) on a single battery charge.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More heavily discounted: Has been available for much longer (launched in September 2006).

Advantages of the Pentax K-S2:

• More detail: Has more megapixels (20 vs 10MP), which boosts linear resolution by 44%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Is equipped with a larger and more technologically advanced sensor.
• Richer colors: The sensor size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger sensor captures a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger sensor produces good images even in poorly lit environments.
• Broader imaging potential: Can capture not only stills but also 1080/30p video.
• 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 (0.63x vs 0.46x).
• Larger screen: Has a bigger rear LCD (3.0" vs 2.5") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 215k dots).
• More flexible LCD: Has a swivel 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 (1/6000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (5.4 vs 3 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• 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 file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More modern: Reflects 8 years and 4 months of technical progress since the E-400 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the K-S2 is the clear winner of the contest (21 : 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 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 Olympus E-400 and the Pentax K-S2 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 specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the E-400 or the K-S2 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 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	Street Price
1.		Olympus E-400	..	85/100	..	..	4/5	4/5	Sep 2006	US$ 699	ebay.com
2.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	US$ 749	ebay.com
3.		Nikon D40X	..	79/100	..	+ +	4/5	4/5	Mar 2007	US$ 729	ebay.com
4.		Olympus E-410	..	86/100	..	+ +	4/5	4.5/5	Mar 2007	US$ 699	ebay.com
5.		Olympus E-420	..	85/100	..	+ +	4/5	4.5/5	Mar 2008	US$ 599	ebay.com
6.		Olympus E-450	..	..	..	..	4/5	4/5	Mar 2009	US$ 499	ebay.com
7.		Olympus E-500	..	76/100	..	+ +	..	..	Sep 2005	US$ 599	ebay.com
8.		Olympus E-510	..	89/100	..	+ +	3.5/5	4.5/5	Mar 2007	US$ 799	ebay.com
9.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	US$ 699	ebay.com
10.		Olympus Stylus 1	..	+ +	..	..	4.5/5	4.5/5	Oct 2013	US$ 699	ebay.com
11.		Olympus Stylus 1s	..	..	..	..	..	..	Apr 2015	US$ 699	ebay.com
12.		Panasonic L10	..	85/100	..	+	3.5/5	4/5	Aug 2007	US$ 599	ebay.com
13.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	US$ 1 299	ebay.com
14.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	US$ 1 099	ebay.com
15.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	US$ 649	ebay.com
16.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	US$ 1 099	ebay.com
17.		Pentax K-S1	4/5	..	..	..	4.5/5	4/5	Aug 2014	US$ 749	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. 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

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