Olympus E-P1 vs Pentax 645Z

The Olympus PEN E-P1 and the Pentax 645Z are two digital cameras that were announced, respectively, in June 2009 and April 2014. The E-P1 is a mirrorless interchangeable lens camera, while the 645Z is a DSLR. The cameras are based on a Four Thirds (E-P1) and a medium format (645Z) sensor. The Olympus has a resolution of 12.2 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-P1		Pentax 645Z
Mirrorless system camera		Digital single lens reflex
Micro Four Thirds lenses		Pentax 645 mount lenses
12.2 MP – Four Thirds sensor		51.1 MP – Medium Format sensor
720/30p Video		1080/60i Video
ISO 100-6,400		ISO 100-204,800
No viewfinder, LCD framing		Optical viewfinder
3.0" LCD – 230k dots		3.2" LCD – 1037k dots
Fixed screen (not touch-sensitive)		Tilting screen (no touchscreen)
3 shutter flaps per second		3 shutter flaps per second
In-body stabilization		Lens stabilization only
not weather sealed		Weathersealed body
300 shots per battery charge		650 shots per battery charge
121 x 70 x 36 mm, 355 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 PEN E-P1 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

The side-by-side display below illustrates the physical size and weight of the Olympus E-P1 and the Pentax 645Z. 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 measures are rounded to the nearest millimeter.

The E-P1 can be obtained in three different colors (black, silver, white), while the 645Z 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 645Z is considerably larger (115 percent) than the Olympus E-P1. Moreover, the 645Z is substantially heavier (337 percent) than the E-P1. It is noteworthy in this context that the 645Z is splash and dust-proof, while the E-P1 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-P1 gets 300 shots out of its Olympus BLS-1 battery, while the 645Z can take 650 images on a single charge of its Pentax D-LI90 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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-P1	121 mm	70 mm	36 mm	355 g	300	n	Jun 2009	799	ebay.com
2.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	8,499	ebay.com
3.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
4.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
5.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	8,995	ebay.com
6.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	7,450	ebay.com
7.		Olympus E-P3	122 mm	69 mm	34 mm	369 g	330	n	Jun 2011	799	ebay.com
8.		Olympus E-PL2	114 mm	72 mm	42 mm	362 g	280	n	Jan 2011	599	ebay.com
9.		Olympus E-PL3	110 mm	64 mm	37 mm	313 g	300	n	Jun 2011	599	ebay.com
10.		Olympus E-PL1	115 mm	72 mm	42 mm	334 g	290	n	Feb 2010	599	ebay.com
11.		Olympus E-620	130 mm	94 mm	60 mm	521 g	500	n	Feb 2009	699	ebay.com
12.		Olympus E-P2	121 mm	70 mm	36 mm	355 g	300	n	Nov 2009	799	ebay.com
13.		Olympus E-520	136 mm	92 mm	68 mm	535 g	750	n	May 2008	699	ebay.com
14.		Panasonic G10	124 mm	84 mm	74 mm	388 g	380	n	Mar 2010	499	ebay.com
15.		Panasonic GF1	119 mm	71 mm	36 mm	385 g	380	n	Sep 2009	749	ebay.com
16.		Panasonic GH1	124 mm	90 mm	45 mm	385 g	300	n	Mar 2009	899	ebay.com
17.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	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-P1 was launched at a markedly lower price (by 91 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. 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 imaging sensor is a crucial determinant 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. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its 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-P1 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-P1 (12.2MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 4.29μm for the E-P1) due to its larger sensor. Moreover, the 645Z is a much more recent model (by 4 years and 9 months) than the E-P1, 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-P1 are 20.2 x 15.1 inches or 51.2 x 38.4 cm for good quality, 16.1 x 12.1 inches or 41 x 30.7 cm for very good quality, and 13.4 x 10.1 inches or 34.1 x 25.6 cm for excellent quality prints.

The Olympus PEN E-P1 has a native sensitivity range from ISO 100 to ISO 6400. 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.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. This service determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). Of the two cameras under consideration, the 645Z offers substantially better image quality than the E-P1 (overall score 46 points higher). The advantage is based on 4.6 bits higher color depth, 4.3 EV in additional dynamic range, and 3.1 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-P1	Four Thirds	12.2	4032	3024	720/30p	21.4	10.4	536	55
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.		Olympus E-P3	Four Thirds	12.2	4032	3024	1080/60i	20.8	10.1	536	51
8.		Olympus E-PL2	Four Thirds	12.2	4032	3024	720/30p	21.4	10.2	573	55
9.		Olympus E-PL3	Four Thirds	12.2	4032	3024	1080/60i	20.9	10.3	499	52
10.		Olympus E-PL1	Four Thirds	12.2	4032	3024	720/30p	21.5	10.1	487	54
11.		Olympus E-620	Four Thirds	12.2	4032	3024	none	21.3	10.3	536	55
12.		Olympus E-P2	Four Thirds	12.2	4032	3024	720/30p	21.5	10.4	505	56
13.		Olympus E-520	Four Thirds	10.0	3648	2736	none	21.4	10.4	548	55
14.		Panasonic G10	Four Thirds	12.0	4000	3000	720/30p	21.2	10.1	411	52
15.		Panasonic GF1	Four Thirds	12.0	4000	3000	720/30p	21.2	10.3	513	54
16.		Panasonic GH1	Four Thirds	12.0	4000	3000	1080/24p	21.6	11.6	772	64
17.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82

Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the 645Z provides a better video resolution than the E-P1. It can shoot movie footage at 1080/60i, while the Olympus is limited to 720/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the 645Z has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the E-P1 relies on live view and the rear LCD for framing. The following table reports on some other key feature differences and similarities of the Olympus E-P1, 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-P1	none	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	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.		Olympus E-P3	optional	n	3.0 / 614	fixed	Y	1/4000s	3.0/s	Y	Y
8.		Olympus E-PL2	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	Y
9.		Olympus E-PL3	optional	n	3.0 / 460	tilting	n	1/4000s	5.5/s	n	Y
10.		Olympus E-PL1	optional	n	2.7 / 230	fixed	n	1/2000s	3.0/s	Y	Y
11.		Olympus E-620	optical	n	2.7 / 230	swivel	n	1/4000s	4.0/s	Y	Y
12.		Olympus E-P2	optional	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
13.		Olympus E-520	optical	n	2.7 / 215	fixed	n	1/4000s	3.5/s	Y	Y
14.		Panasonic G10	202	n	3.0 / 460	fixed	n	1/4000s	2.6/s	Y	n
15.		Panasonic GF1	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	n
16.		Panasonic GH1	1440	n	3.0 / 460	swivel	n	1/4000s	3.0/s	Y	n
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 feature that differentiates the E-P1 and the 645Z is in-body image stabilization (IBIS). The E-P1 reduces the risk of handshake-induced blur with all attached lenses, while the 645Z offers no blur reduction with lenses that themselves do not provide optical image stabilization.

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-P1 writes its imaging data to SDHC cards, while the 645Z uses SDXC cards. The 645Z features dual card slots, which can be very useful in case a memory card fails. In contrast, the E-P1 only has one slot. The 645Z supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the E-P1 cannot take advantage of Ultra High Speed SD 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 Olympus PEN E-P1 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-P1	Y	stereo / -	-	-	mini	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.		Olympus E-P3	Y	stereo / -	-	-	mini	2.0	-	-	-
8.		Olympus E-PL2	Y	stereo / -	-	-	mini	2.0	-	-	-
9.		Olympus E-PL3	Y	stereo / -	-	-	mini	2.0	-	-	-
10.		Olympus E-PL1	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Olympus E-620	Y	- / -	-	-	-	2.0	-	-	-
12.		Olympus E-P2	Y	stereo / -	-	-	mini	2.0	-	-	-
13.		Olympus E-520	Y	- / -	-	-	-	2.0	-	-	-
14.		Panasonic G10	Y	mono / -	-	-	mini	2.0	-	-	-
15.		Panasonic GF1	Y	mono / mono	-	-	mini	2.0	-	-	-
16.		Panasonic GH1	Y	stereo / -	Y	-	mini	2.0	-	-	-
17.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-

It is notable that the 645Z has a microphone port, which can help to improve the quality of audio recordings by attaching an external microphone. The E-P1 does not feature such a mic input.

Studio photographers will appreciate that the Pentax 645Z (unlike the E-P1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the E-P1 and the 645Z have been discontinued, but can regularly be found used on ebay. The E-P1 was replaced by the Olympus E-P2, while the 645Z does not have a direct successor. Further information on the features and operation of the E-P1 and 645Z can be found, respectively, in the Olympus E-P1 Manual (free pdf) or the online Pentax 645Z Manual.

Review summary

So what is the bottom line? Is the Olympus E-P1 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 PEN E-P1:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• More compact: Is smaller (121x70mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 1195g or 77 percent) and hence easier to carry around.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• More affordable: Was introduced into a lower priced category (91 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in June 2009).

Arguments in favor of the Pentax 645Z:

• More detail: Has more megapixels (51.1 vs 12.2MP), which boosts linear resolution by 105%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores substantially higher (46 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (4.6 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (4.3 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (3.1 stops ISO advantage).
• Better video: Provides higher definition movie capture (1080/60i vs 720/30p).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (1037k vs 230k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Gets more shots (650 versus 300) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Reflects 4 years and 9 months of technical progress since the E-P1 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the 645Z is the clear winner of the contest (21 : 7 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 Olympus E-P1 and the Pentax 645Z place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best DSLR Camera listings 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 remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the E-P1 or the 645Z. 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 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 (USD)	Street Price
1.		Olympus E-P1	..	+	..	66/100	4/5	4.5/5	Jun 2009	799	ebay.com
2.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	ebay.com
3.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	3,699	ebay.com
4.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	3,699	ebay.com
5.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	8,995	ebay.com
6.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	7,450	ebay.com
7.		Olympus E-P3	..	83/100	..	74/100	4.5/5	4.5/5	Jun 2011	799	ebay.com
8.		Olympus E-PL2	3/5	83/100	..	71/100	4.5/5	4.5/5	Jan 2011	599	ebay.com
9.		Olympus E-PL3	3/5	+ +	..	72/100	4.5/5	4/5	Jun 2011	599	ebay.com
10.		Olympus E-PL1	..	86/100	..	69/100	4/5	4.5/5	Feb 2010	599	ebay.com
11.		Olympus E-620	3/5	88/100	..	72/100	4.5/5	5/5	Feb 2009	699	ebay.com
12.		Olympus E-P2	3/5	+	..	69/100	4/5	4.5/5	Nov 2009	799	ebay.com
13.		Olympus E-520	..	87/100	..	+ +	4.5/5	4.5/5	May 2008	699	ebay.com
14.		Panasonic G10	3/5	..	..	70/100	4/5	4/5	Mar 2010	499	ebay.com
15.		Panasonic GF1	..	85/100	..	69/100	4.5/5	4.5/5	Sep 2009	749	ebay.com
16.		Panasonic GH1	..	+ +	..	72/100	4.5/5	4.5/5	Mar 2009	899	ebay.com
17.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	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 comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

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Other camera comparisons

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