Olympus E-3 vs Pentax K-3

The Olympus E-3 and the Pentax K-3 are two digital cameras that were officially introduced, respectively, in October 2007 and October 2013. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a Four Thirds (E-3) and an APS-C (K-3) sensor. The Olympus has a resolution of 10 megapixels, whereas the Pentax provides 24.1 MP.

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

Headline Specifications

Olympus E-3		Pentax K-3
Digital single lens reflex		Digital single lens reflex
Four Thirds lenses		Pentax K mount lenses
10 MP – Four Thirds sensor		24.1 MP – APS-C sensor
no Video		1080/60i Video
ISO 100-3,200		ISO 100-51,200
Optical viewfinder		Optical viewfinder
2.5" LCD – 230k dots		3.2" LCD – 1037k dots
Swivel screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
5 shutter flaps per second		8.3 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
750 shots per battery charge		560 shots per battery charge
142 x 116 x 75 mm, 876 g		131 x 100 x 77 mm, 800 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus E-3 and the Pentax K-3? 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-3 and the Pentax K-3 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-3 can be obtained in two different colors (black, silver), while the E-3 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-3 is notably smaller (20 percent) than the Olympus E-3. Moreover, the K-3 is markedly lighter (9 percent) than the E-3. 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 E-3 gets 750 shots out of its Olympus BLM-1 battery, while the K-3 can take 560 images on a single charge of its Pentax D-LI90 power pack.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.		Olympus E-3	142 mm	116 mm	75 mm	876 g	750	Y	Oct 2007	1,699	ebay.com
2.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
3.		Nikon D300	147 mm	114 mm	74 mm	925 g	1000	Y	Aug 2007	1,799	ebay.com
4.		Nikon D7100	136 mm	107 mm	76 mm	765 g	950	Y	Feb 2013	1,199	ebay.com
5.		Olympus E-1	141 mm	104 mm	81 mm	738 g	750	Y	Jun 2003	1,699	ebay.com
6.		Olympus E-5	142 mm	117 mm	75 mm	873 g	750	Y	Sep 2010	1,699	ebay.com
7.		Olympus E-30	142 mm	108 mm	75 mm	701 g	750	n	Nov 2008	1,299	ebay.com
8.		Olympus E-410	130 mm	91 mm	53 mm	435 g	500	n	Mar 2007	699	ebay.com
9.		Olympus E-420	130 mm	91 mm	53 mm	440 g	500	n	Mar 2008	599	ebay.com
10.		Olympus E-510	136 mm	92 mm	68 mm	538 g	750	n	Mar 2007	799	ebay.com
11.		Olympus E-520	136 mm	92 mm	68 mm	535 g	750	n	May 2008	699	ebay.com
12.		Olympus E-600	130 mm	94 mm	60 mm	535 g	500	n	Aug 2009	449	ebay.com
13.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	699	ebay.com
14.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
15.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	1,099	ebay.com
16.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
17.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	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 manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The K-3 was launched at a somewhat lower price (by 24 percent) than the E-3, which makes it more attractive for photographers on a tight budget. 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 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

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

With 24.1MP, the K-3 offers a higher resolution than the E-3 (10MP), but the K-3 has smaller individual pixels (pixel pitch of 3.90μm versus 4.74μm for the E-3). Yet, the K-3 is a much more recent model (by 5 years and 11 months) than the E-3, 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-3 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax K-3 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-3 for good quality output (200 dots per inch) amounts to 30.1 x 20 inches or 76.4 x 50.8 cm, for very good quality (250 dpi) 24.1 x 16 inches or 61.1 x 40.6 cm, and for excellent quality (300 dpi) 20.1 x 13.3 inches or 50.9 x 33.9 cm. The corresponding values for the Olympus E-3 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-3 has a native sensitivity range from ISO 100 to ISO 3200. The corresponding ISO settings for the Pentax K-3 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 assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. Of the two cameras under consideration, the K-3 offers substantially better image quality than the E-3 (overall score 24 points higher). The advantage is based on 2.1 bits higher color depth, 2.9 EV in additional dynamic range, and 1.1 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-3	Four Thirds	10.0	3648	2736	none	21.6	10.5	571	56
2.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
3.		Nikon D300	APS-C	12.2	4288	2848	none	22.1	12.0	679	67
4.		Nikon D7100	APS-C	24.0	6000	4000	1080/60p	24.2	13.7	1256	83
5.		Olympus E-1	Four Thirds	4.9	2560	1920	none	20.0	9.7	-145	44
6.		Olympus E-5	Four Thirds	12.2	4032	3024	720/30p	21.6	10.5	519	56
7.		Olympus E-30	Four Thirds	12.2	4032	3024	none	21.3	10.4	530	55
8.		Olympus E-410	Four Thirds	10.0	3648	2736	none	21.1	10.0	494	51
9.		Olympus E-420	Four Thirds	10.0	3648	2736	none	21.5	10.4	527	56
10.		Olympus E-510	Four Thirds	10.0	3648	2736	none	21.2	10.0	442	52
11.		Olympus E-520	Four Thirds	10.0	3648	2736	none	21.4	10.4	548	55
12.		Olympus E-600	Four Thirds	12.2	4032	3024	none	21.5	10.3	541	55
13.		Olympus E-620	Four Thirds	12.2	4032	3024	none	21.3	10.3	536	55
14.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
15.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
16.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
17.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
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 K-3 indeed provides for movie recording, while the E-3 does not. The highest resolution format that the K-3 can use is 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The E-3 and the K-3 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 viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the K-3 has a higher magnification than the one of the E-3 (0.63x vs 0.58x), 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-3 and Pentax K-3 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-3	optical	Y	2.5 / 230	swivel	n	1/8000s	5.0/s	Y	Y
2.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
3.		Nikon D300	optical	Y	3.0 / 922	fixed	n	1/8000s	6.0/s	Y	n
4.		Nikon D7100	optical	Y	3.2 / 1229	fixed	n	1/8000s	6.0/s	Y	n
5.		Olympus E-1	optical	Y	1.8 / 134	fixed	n	1/4000s	3.0/s	n	n
6.		Olympus E-5	optical	Y	3.0 / 920	swivel	n	1/8000s	5.0/s	Y	Y
7.		Olympus E-30	optical	Y	2.7 / 230	swivel	n	1/8000s	5.0/s	Y	Y
8.		Olympus E-410	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	n
9.		Olympus E-420	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
10.		Olympus E-510	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	Y
11.		Olympus E-520	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	Y
12.		Olympus E-600	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
13.		Olympus E-620	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/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-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
16.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
17.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

The Pentax K-3 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-3 writes its imaging data to Compact Flash or xD Picture cards, while the K-3 uses SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails.

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-3 and Pentax K-3 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-3	Y	- / -	-	-	-	2.0	-	-	-
2.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
3.		Nikon D300	Y	- / -	-	-	mini	2.0	-	-	-
4.		Nikon D7100	Y	stereo / mono	Y	Y	mini	2.0	-	-	-
5.		Olympus E-1	Y	- / -	-	-	-	2.0	-	-	-
6.		Olympus E-5	Y	stereo / -	-	-	mini	2.0	-	-	-
7.		Olympus E-30	Y	- / -	-	-	-	2.0	-	-	-
8.		Olympus E-410	Y	- / -	-	-	-	2.0	-	-	-
9.		Olympus E-420	Y	- / -	-	-	-	2.0	-	-	-
10.		Olympus E-510	Y	- / -	-	-	-	2.0	-	-	-
11.		Olympus E-520	Y	- / -	-	-	-	2.0	-	-	-
12.		Olympus E-600	Y	- / -	-	-	-	2.0	-	-	-
13.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
14.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
17.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-

Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.

Both the E-3 and the K-3 have been discontinued, but can regularly be found used on ebay. The E-3 was replaced by the Olympus E-5, while the K-3 was followed by the Pentax K-3 II. Further information on the features and operation of the E-3 and K-3 can be found, respectively, in the Olympus E-3 Manual (free pdf) or the online Pentax K-3 Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Olympus E-3 or the Pentax K-3 – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Olympus E-3:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• 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.
• Longer lasting: Can take more shots (750 versus 560) on a single battery charge.
• More heavily discounted: Has been available for much longer (launched in October 2007).

Advantages of the Pentax K-3:

• More detail: Has more megapixels (24.1 vs 10MP), which boosts linear resolution by 58%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (24 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (2.1 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (2.9 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (1.1 stops ISO advantage).
• Broader imaging potential: Can capture not only stills but also 1080/60i video.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.63x vs 0.58x).
• Larger screen: Has a bigger rear LCD (3.2" vs 2.5") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (1037k vs 230k dots).
• Faster burst: Shoots at higher frequency (8.3 vs 5 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (131x100mm vs 142x116mm) and will fit more readily into a bag.
• Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
• More affordable: Was released into a lower priced segment (24 percent cheaper at launch).
• More modern: Reflects 5 years and 11 months of technical progress since the E-3 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the K-3 is the clear winner of the contest (16 : 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-3 and the Pentax K-3 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 says little about, for example, the shooting experience and imaging performance of the E-3 and the K-3 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 expert reviews are important. The table below provides a synthesis of the camera assessments of some of the best known photo-gear 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-3	..	88/100	..	+ +	o	4/5	Oct 2007	1,699	ebay.com
2.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
3.		Nikon D300	..	+ +	..	+ +	5/5	4.5/5	Aug 2007	1,799	ebay.com
4.		Nikon D7100	5/5	+ +	..	85/100	4.5/5	4.5/5	Feb 2013	1,199	ebay.com
5.		Olympus E-1	..	..	..	+	o	..	Jun 2003	1,699	ebay.com
6.		Olympus E-5	4/5	..	..	75/100	4/5	4.5/5	Sep 2010	1,699	ebay.com
7.		Olympus E-30	..	..	..	71/100	4.5/5	4/5	Nov 2008	1,299	ebay.com
8.		Olympus E-410	..	86/100	..	+ +	4/5	4.5/5	Mar 2007	699	ebay.com
9.		Olympus E-420	..	85/100	..	+ +	4/5	4.5/5	Mar 2008	599	ebay.com
10.		Olympus E-510	..	89/100	..	+ +	3.5/5	4.5/5	Mar 2007	799	ebay.com
11.		Olympus E-520	..	87/100	..	+ +	4.5/5	4.5/5	May 2008	699	ebay.com
12.		Olympus E-600	..	..	..	..	..	4.5/5	Aug 2009	449	ebay.com
13.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	699	ebay.com
14.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
15.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	1,099	ebay.com
16.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
17.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	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. 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

Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. 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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