Olympus E-3 vs Pentax 645Z

The Olympus E-3 and the Pentax 645Z are two professional cameras that were announced, respectively, in October 2007 and April 2014. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a Four Thirds (E-3) and a medium format (645Z) sensor. The Olympus has a resolution of 10 megapixels, whereas the Pentax provides 51.1 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 645Z
Digital single lens reflex		Digital single lens reflex
Four Thirds lenses		Pentax 645 mount lenses
10 MP – Four Thirds sensor		51.1 MP – Medium Format sensor
no Video		1080/60i Video
ISO 100-3,200		ISO 100-204,800
Optical viewfinder		Optical viewfinder
2.5" LCD – 230k dots		3.2" LCD – 1037k dots
Swivel screen (not touch-sensitive)		Tilting screen (no touchscreen)
5 shutter flaps per second		3 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		Weathersealed body
750 shots per battery charge		650 shots per battery charge
142 x 116 x 75 mm, 876 g		156 x 117 x 123 mm, 1550 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 645Z? 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 Olympus E-3 and the Pentax 645Z 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.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax 645Z is notably larger (11 percent) than the Olympus E-3. Moreover, the 645Z is substantially heavier (77 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 645Z can take 650 images on a single charge of its Pentax D-LI90 power pack.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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-3	142 mm	116 mm	75 mm	876 g	750	Y	Oct 2007	US$ 1 699	ebay.com
2.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	US$ 8 499	ebay.com
3.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	US$ 3 699	ebay.com
4.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	US$ 3 699	ebay.com
5.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	US$ 8 995	ebay.com
6.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	US$ 7 449	ebay.com
7.		Nikon D300	147 mm	114 mm	74 mm	925 g	1000	Y	Aug 2007	US$ 1 799	ebay.com
8.		Olympus E-1	141 mm	104 mm	81 mm	738 g	750	Y	Jun 2003	US$ 1 699	ebay.com
9.		Olympus E-5	142 mm	117 mm	75 mm	873 g	750	Y	Sep 2010	US$ 1 699	ebay.com
10.		Olympus E-30	142 mm	108 mm	75 mm	701 g	750	n	Nov 2008	US$ 1 299	ebay.com
11.		Olympus E-410	130 mm	91 mm	53 mm	435 g	500	n	Mar 2007	US$ 699	ebay.com
12.		Olympus E-420	130 mm	91 mm	53 mm	440 g	500	n	Mar 2008	US$ 599	ebay.com
13.		Olympus E-510	136 mm	92 mm	68 mm	538 g	750	n	Mar 2007	US$ 799	ebay.com
14.		Olympus E-520	136 mm	92 mm	68 mm	535 g	750	n	May 2008	US$ 699	ebay.com
15.		Olympus E-600	130 mm	94 mm	60 mm	535 g	500	n	Aug 2009	US$ 449	ebay.com
16.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	US$ 699	ebay.com
17.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	US$ 9 995	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 E-3 was launched at a markedly lower price (by 80 percent) than the 645Z, 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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 more expensive and 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 645Z a medium format sensor. The sensor area in the 645Z is 539 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 0.79. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.

With 51.1MP, the 645Z offers a higher resolution than the E-3 (10MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 4.74μm for the E-3) due to its larger sensor. Moreover, the 645Z is a much more recent model (by 6 years and 6 months) than the E-3, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the 645Z has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax 645Z implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 645Z for good quality output (200 dots per inch) amounts to 41.3 x 31 inches or 104.9 x 78.6 cm, for very good quality (250 dpi) 33 x 24.8 inches or 83.9 x 62.9 cm, and for excellent quality (300 dpi) 27.5 x 20.6 inches or 69.9 x 52.4 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 645Z are ISO 100 to ISO 204800 (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.

For many cameras, data on sensor performance has been reported by DXO Mark. 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 645Z offers substantially better image quality than the E-3 (overall score 45 points higher). The advantage is based on 4.4 bits higher color depth, 4.2 EV in additional dynamic range, and 3 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.		Olympus E-3	Four Thirds	10.0	3648	2736	none	21.6	10.5	571	56
2.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
3.		Canon 5DS	Full Frame	50.3	8688	5792	1080/30p	24.7	12.4	2381	87
4.		Canon 5DS R	Full Frame	50.3	8688	5792	1080/30p	24.6	12.4	2308	86
5.		Hasselblad X1D	Medium Format	51.3	8272	6200	1080/25p	26.2	14.8	4489	102
6.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
7.		Nikon D300	APS-C	12.2	4288	2848	none	22.1	12.0	679	67
8.		Olympus E-1	Four Thirds	4.9	2560	1920	none	20.0	9.7	-145	44
9.		Olympus E-5	Four Thirds	12.2	4032	3024	720/30p	21.6	10.5	519	56
10.		Olympus E-30	Four Thirds	12.2	4032	3024	none	21.3	10.4	530	55
11.		Olympus E-410	Four Thirds	10.0	3648	2736	none	21.1	10.0	494	51
12.		Olympus E-420	Four Thirds	10.0	3648	2736	none	21.5	10.4	527	56
13.		Olympus E-510	Four Thirds	10.0	3648	2736	none	21.2	10.0	442	52
14.		Olympus E-520	Four Thirds	10.0	3648	2736	none	21.4	10.4	548	55
15.		Olympus E-600	Four Thirds	12.2	4032	3024	none	21.5	10.3	541	55
16.		Olympus E-620	Four Thirds	12.2	4032	3024	none	21.3	10.3	536	55
17.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
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 645Z indeed provides for movie recording, while the E-3 does not. The highest resolution format that the 645Z can use is 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The E-3 and the 645Z 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 E-3 offers a wider field of view (100%) than the one in the 645Z (98%), so that a larger proportion of the captured image is visible in the finder. On the other hand, the viewfinder of the 645Z has a higher magnification (0.78x vs 0.58x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The following table reports on some other key feature differences and similarities of the Olympus E-3, the Pentax 645Z, and comparable cameras.

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 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
3.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
4.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
5.		Hasselblad X1D	2360	n	3.0 / 920	fixed	Y	1/2000s	2.3/s	n	n
6.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
7.		Nikon D300	optical	Y	3.0 / 922	fixed	n	1/8000s	6.0/s	Y	n
8.		Olympus E-1	optical	Y	1.8 / 134	fixed	n	1/4000s	3.0/s	n	n
9.		Olympus E-5	optical	Y	3.0 / 920	swivel	n	1/8000s	5.0/s	Y	Y
10.		Olympus E-30	optical	Y	2.7 / 230	swivel	n	1/8000s	5.0/s	Y	Y
11.		Olympus E-410	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	n
12.		Olympus E-420	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	n
13.		Olympus E-510	optical	n	2.5 / 215	fixed	n	1/4000s	3.0/s	Y	Y
14.		Olympus E-520	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	Y
15.		Olympus E-600	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
16.		Olympus E-620	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
17.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One difference between the cameras concerns the presence of an on-board flash. The E-3 has one, while the 645Z does not. While the built-in flash of the E-3 is not very powerful, it can at times be useful as a fill-in light.

The Pentax 645Z 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 645Z 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 645Z 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 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-
3.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
4.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
5.		Hasselblad X1D	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
6.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
7.		Nikon D300	Y	- / -	-	-	mini	2.0	-	-	-
8.		Olympus E-1	Y	- / -	-	-	-	2.0	-	-	-
9.		Olympus E-5	Y	stereo / -	-	-	mini	2.0	-	-	-
10.		Olympus E-30	Y	- / -	-	-	-	2.0	-	-	-
11.		Olympus E-410	Y	- / -	-	-	-	2.0	-	-	-
12.		Olympus E-420	Y	- / -	-	-	-	2.0	-	-	-
13.		Olympus E-510	Y	- / -	-	-	-	2.0	-	-	-
14.		Olympus E-520	Y	- / -	-	-	-	2.0	-	-	-
15.		Olympus E-600	Y	- / -	-	-	-	2.0	-	-	-
16.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
17.		Pentax 645D	Y	stereo / -	-	-	-	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 645Z have been discontinued, but can regularly be found used on ebay. The E-3 was replaced by the Olympus E-5, while the 645Z does not have a direct successor. Further information on the features and operation of the E-3 and 645Z can be found, respectively, in the Olympus E-3 Manual (free pdf) or the online Pentax 645Z Manual.

Review summary

So how do things add up? Is the Olympus E-3 better than the Pentax 645Z or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Olympus E-3:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• More complete view: Has a viewfinder with a larger field of view (100% vs 98%).
• 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 (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (5 vs 3 flaps/sec) to capture the decisive moment.
• Less heavy: Is lighter (by 674g or 43 percent) and hence easier to carry around.
• Longer lasting: Can take more shots (750 versus 650) on a single battery charge.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (80 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in October 2007).

Arguments in favor of the Pentax 645Z:

• More detail: Has more megapixels (51.1 vs 10MP), which boosts linear resolution by 126%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (45 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (4.4 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (4.2 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (3 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 (0.78x 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).
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
• More modern: Reflects 6 years and 6 months of technical progress since the E-3 launch.

If the number of relative strengths (bullet points above) is taken as a guide, the 645Z comes out slightly ahead of the E-3 (13 : 12 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 645Z 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 E-3 or the 645Z 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 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	Street Price
1.		Olympus E-3	..	88/100	..	+ +	o	4/5	Oct 2007	US$ 1 699	ebay.com
2.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	US$ 8 499	ebay.com
3.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	US$ 3 699	ebay.com
4.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	US$ 3 699	ebay.com
5.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	US$ 8 995	ebay.com
6.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	US$ 7 449	ebay.com
7.		Nikon D300	..	+ +	..	+ +	5/5	4.5/5	Aug 2007	US$ 1 799	ebay.com
8.		Olympus E-1	..	..	..	+	o	..	Jun 2003	US$ 1 699	ebay.com
9.		Olympus E-5	4/5	..	..	75/100	4/5	4.5/5	Sep 2010	US$ 1 699	ebay.com
10.		Olympus E-30	..	..	..	71/100	4.5/5	4/5	Nov 2008	US$ 1 299	ebay.com
11.		Olympus E-410	..	86/100	..	+ +	4/5	4.5/5	Mar 2007	US$ 699	ebay.com
12.		Olympus E-420	..	85/100	..	+ +	4/5	4.5/5	Mar 2008	US$ 599	ebay.com
13.		Olympus E-510	..	89/100	..	+ +	3.5/5	4.5/5	Mar 2007	US$ 799	ebay.com
14.		Olympus E-520	..	87/100	..	+ +	4.5/5	4.5/5	May 2008	US$ 699	ebay.com
15.		Olympus E-600	..	..	..	..	..	4.5/5	Aug 2009	US$ 449	ebay.com
16.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	US$ 699	ebay.com
17.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	US$ 9 995	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Hence, a score should always be seen in the context of the camera's market launch date and its price, 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.

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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 a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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