Panasonic GX1 vs Pentax 645Z

The Panasonic Lumix DMC-GX1 and the Pentax 645Z are two digital cameras that were announced, respectively, in November 2011 and April 2014. The GX1 is a mirrorless interchangeable lens camera, while the 645Z is a DSLR. The cameras are based on a Four Thirds (GX1) and a medium format (645Z) sensor. The Panasonic has a resolution of 15.8 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

Panasonic GX1		Pentax 645Z
Mirrorless system camera		Digital single lens reflex
Micro Four Thirds lenses		Pentax 645 mount lenses
15.8 MP – Four Thirds sensor		51.1 MP – Medium Format sensor
1080/60p Video		1080/60i Video
ISO 160-12,800		ISO 100-204,800
Viewfinder optional		Optical viewfinder
3.0" LCD – 460k dots		3.2" LCD – 1037k dots
Fixed touchscreen		Tilting screen (no touchscreen)
4.2 shutter flaps per second		3 shutter flaps per second
not weather sealed		Weathersealed body
320 shots per battery charge		650 shots per battery charge
116 x 68 x 39 mm, 318 g		156 x 117 x 123 mm, 1550 g

Check GX1 offers at
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Check 645Z offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Panasonic Lumix DMC-GX1 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 physical size and weight of the Panasonic GX1 and the Pentax 645Z are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side are shown. 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 Pentax 645Z is considerably larger (131 percent) than the Panasonic GX1. Moreover, the 645Z is substantially heavier (387 percent) than the GX1. It is noteworthy in this context that the 645Z is splash and dust-proof, while the GX1 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 GX1 gets 320 shots out of its Panasonic DMW-BLD10 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. 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.		Panasonic GX1	116 mm	68 mm	39 mm	318 g	320	n	Nov 2011	699	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.		Panasonic G2	124 mm	84 mm	74 mm	428 g	360	n	Mar 2010	599	ebay.com
8.		Panasonic G3	115 mm	84 mm	47 mm	336 g	270	n	May 2011	599	ebay.com
9.		Panasonic G5	120 mm	83 mm	71 mm	396 g	320	n	Jul 2012	599	ebay.com
10.		Panasonic G6	122 mm	85 mm	71 mm	390 g	340	n	Apr 2013	599	ebay.com
11.		Panasonic GF1	119 mm	71 mm	36 mm	385 g	380	n	Sep 2009	749	ebay.com
12.		Panasonic GF2	113 mm	68 mm	33 mm	310 g	300	n	Nov 2010	549	ebay.com
13.		Panasonic GF3	108 mm	67 mm	32 mm	264 g	300	n	Jun 2011	549	ebay.com
14.		Panasonic GF5	108 mm	67 mm	37 mm	267 g	360	n	Apr 2012	499	ebay.com
15.		Panasonic GH2	124 mm	90 mm	76 mm	442 g	330	n	Sep 2010	899	ebay.com
16.		Panasonic GM1	99 mm	55 mm	30 mm	204 g	230	n	Oct 2013	749	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 naturally be influenced heavily by the price. 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 GX1 was launched at a markedly lower price (by 92 percent) than the 645Z, which puts it into a different market segment. 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.

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 Panasonic GX1 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 GX1 (15.8MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 3.77μm for the GX1) due to its larger sensor. Moreover, the 645Z is a much more recent model (by 2 years and 5 months) than the GX1, 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 Panasonic GX1 are 23 x 17.2 inches or 58.3 x 43.8 cm for good quality, 18.4 x 13.8 inches or 46.7 x 35 cm for very good quality, and 15.3 x 11.5 inches or 38.9 x 29.2 cm for excellent quality prints.

The Panasonic Lumix DMC-GX1 has a native sensitivity range from ISO 160 to ISO 12800. 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.

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 645Z offers substantially better image quality than the GX1 (overall score 46 points higher). The advantage is based on 5.2 bits higher color depth, 4.1 EV in additional dynamic range, and 2.7 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.		Panasonic GX1	Four Thirds	15.8	4592	3448	1080/60p	20.8	10.6	703	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.		Panasonic G2	Four Thirds	12.0	4000	3000	720/30p	21.2	10.3	493	53
8.		Panasonic G3	Four Thirds	15.8	4592	3448	1080/60i	21.0	10.6	667	56
9.		Panasonic G5	Four Thirds	15.9	4608	3456	1080/60p	21.4	11.6	618	61
10.		Panasonic G6	Four Thirds	15.9	4608	3456	1080/60p	21.3	11.5	639	61
11.		Panasonic GF1	Four Thirds	12.0	4000	3000	720/30p	21.2	10.3	513	54
12.		Panasonic GF2	Four Thirds	12.0	4000	3000	1080/60i	21.2	10.3	506	54
13.		Panasonic GF3	Four Thirds	12.0	4000	3000	1080/60i	20.6	10.1	459	50
14.		Panasonic GF5	Four Thirds	12.0	4000	3000	1080/60i	20.5	10.0	573	50
15.		Panasonic GH2	Four Thirds	15.9	4608	3456	1080/60i	21.2	11.3	655	60
16.		Panasonic GM1	Four Thirds	15.8	4592	3448	1080/60i	22.3	11.7	660	66
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 also of capturing video footage. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the GX1 provides a higher frame rate than the 645Z. It can shoot video footage at 1080/60p, while the Pentax is limited to 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the 645Z has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the GX1 relies on live view and the rear LCD for framing. That said, the GX1 can be equipped with an optional viewfinder – the DMW-LVF2. The table below summarizes some of the other core capabilities of the Panasonic GX1 and Pentax 645Z in connection with corresponding information for a sample of similar 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.		Panasonic GX1	optional	n	3.0 / 460	fixed	Y	1/4000s	4.2/s	Y	n
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.		Panasonic G2	1440	n	3.0 / 460	swivel	Y	1/4000s	2.6/s	Y	n
8.		Panasonic G3	1440	n	3.0 / 460	swivel	Y	1/4000s	4.0/s	Y	n
9.		Panasonic G5	1440	n	3.0 / 920	swivel	Y	1/4000s	6.0/s	Y	n
10.		Panasonic G6	1440	n	3.0 / 1036	swivel	Y	1/4000s	7.0/s	Y	n
11.		Panasonic GF1	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	n
12.		Panasonic GF2	optional	n	3.0 / 460	fixed	Y	1/4000s	2.6/s	Y	n
13.		Panasonic GF3	none	n	3.0 / 460	fixed	Y	1/4000s	3.2/s	Y	n
14.		Panasonic GF5	none	n	3.0 / 920	fixed	Y	1/4000s	4.0/s	Y	n
15.		Panasonic GH2	1534	n	3.0 / 460	swivel	n	1/4000s	3.0/s	Y	n
16.		Panasonic GM1	none	n	3.0 / 1036	fixed	Y	1/500s	5.0/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 difference between the cameras concerns the presence of an on-board flash. The GX1 has one, while the 645Z does not. While the built-in flash of the GX1 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.

Concerning the storage of imaging data, both the GX1 and the 645Z write their files to SDXC cards. The 645Z features dual card slots, which can be very useful in case a memory card fails. In contrast, the GX1 only has one slot. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.

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 Panasonic Lumix DMC-GX1 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.		Panasonic GX1	Y	stereo / mono	-	-	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.		Panasonic G2	Y	stereo / mono	-	-	mini	2.0	-	-	-
8.		Panasonic G3	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Panasonic G5	Y	stereo / mono	-	-	mini	2.0	-	-	-
10.		Panasonic G6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
11.		Panasonic GF1	Y	mono / mono	-	-	mini	2.0	-	-	-
12.		Panasonic GF2	Y	stereo / mono	-	-	mini	2.0	-	-	-
13.		Panasonic GF3	-	stereo / mono	-	-	mini	2.0	-	-	-
14.		Panasonic GF5	-	stereo / mono	-	-	mini	2.0	-	-	-
15.		Panasonic GH2	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Panasonic GM1	-	stereo / mono	-	-	micro	2.0	Y	-	-
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 GX1 does not feature such a mic input.

Studio photographers will appreciate that the Pentax 645Z (unlike the GX1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the GX1 and the 645Z have been discontinued, but can regularly be found used on ebay. The GX1 was replaced by the Panasonic GX7, while the 645Z does not have a direct successor. Further information on the features and operation of the GX1 and 645Z can be found, respectively, in the Panasonic GX1 Manual (free pdf) or the online Pentax 645Z Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Panasonic GX1 or the Pentax 645Z – 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.

Advantages of the Panasonic Lumix DMC-GX1:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• Faster burst: Shoots at higher frequency (4.2 vs 3 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (116x68mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 1232g or 79 percent) and hence easier to carry around.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (92 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in November 2011).

Reasons to prefer the Pentax 645Z:

• More detail: Has more megapixels (51.1 vs 15.8MP), which boosts linear resolution by 80%.
• 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 (5.2 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (4.1 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (2.7 stops ISO advantage).
• 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 460k 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 320) 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.
• More modern: Reflects 2 years and 5 months of technical progress since the GX1 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the 645Z is the clear winner of the contest (19 : 10 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision 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 Panasonic GX1 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 GX1 or the 645Z. 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 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.		Panasonic GX1	3/5	+	..	77/100	4.5/5	4.5/5	Nov 2011	699	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.		Panasonic G2	..	..	..	72/100	4/5	4.5/5	Mar 2010	599	ebay.com
8.		Panasonic G3	3/5	+ +	..	75/100	4.5/5	5/5	May 2011	599	ebay.com
9.		Panasonic G5	3/5	+ +	..	..	4.5/5	4.5/5	Jul 2012	599	ebay.com
10.		Panasonic G6	4/5	+ +	..	..	5/5	4.5/5	Apr 2013	599	ebay.com
11.		Panasonic GF1	..	85/100	..	69/100	4.5/5	4.5/5	Sep 2009	749	ebay.com
12.		Panasonic GF2	3/5	82/100	..	70/100	4.5/5	4.5/5	Nov 2010	549	ebay.com
13.		Panasonic GF3	3/5	82/100	..	71/100	4.5/5	4/5	Jun 2011	549	ebay.com
14.		Panasonic GF5	3/5	..	..	..	4.5/5	4.5/5	Apr 2012	499	ebay.com
15.		Panasonic GH2	5/5	+ +	..	79/100	4.5/5	5/5	Sep 2010	899	ebay.com
16.		Panasonic GM1	3/5	+	..	78/100	5/5	4.5/5	Oct 2013	749	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, 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 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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