Fujifilm GFX 100 vs Pentax 645Z

The Fujifilm GFX 100 and the Pentax 645Z are two professional cameras that were officially introduced, respectively, in May 2019 and April 2014. The GFX 100 is a mirrorless interchangeable lens camera, while the 645Z is a DSLR. Both cameras are equipped with a medium format sensor. The Fujifilm has a resolution of 101.8 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

Fujifilm GFX 100		Pentax 645Z
Mirrorless system camera		Digital single lens reflex
Fujifilm G mount lenses		Pentax 645 mount lenses
101.8 MP – Medium Format sensor		51.1 MP – Medium Format sensor
4K/30p Video		1080/60i Video
ISO 100-12,800 (50 - 102,400)		ISO 100-204,800
Viewfinder optional		Optical viewfinder
3.2" LCD – 2360k dots		3.2" LCD – 1037k dots
Fully flexible touchscreen		Tilting screen (no touchscreen)
5 shutter flaps per second		3 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		Weathersealed body
800 shots per battery charge		650 shots per battery charge
156 x 144 x 75 mm, 1320 g		156 x 117 x 123 mm, 1550 g

Check GFX 100 offers at
ebay.com
Check 645Z offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Fujifilm GFX 100 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 Fujifilm GFX 100 and the Pentax 645Z are illustrated 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 measures 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 smaller (19 percent) than the Fujifilm GFX 100. However, the 645Z is markedly heavier (17 percent) than the GFX 100. 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 GFX 100 gets 800 shots out of its Fujifilm NP-T125 battery, while the 645Z can take 650 images on a single charge of its Pentax D-LI90 power pack. As can be seen in the images above, the GFX 100 has a battery grip built in. This facilitates image-taking in portrait orientation and gives it additional battery power. The power pack in the GFX 100 can be charged via the USB port, so that it is not always necessary to take the battery charger along when travelling.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.		Fujifilm GFX 100	156 mm	144 mm	75 mm	1320 g	800	Y	May 2019	9,999	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.		Fujifilm GFX 50R	161 mm	97 mm	66 mm	775 g	400	Y	Sep 2018	4,499	ebay.com
6.		Fujifilm GFX 50S	148 mm	94 mm	91 mm	740 g	400	Y	Sep 2016	6,499	ebay.com
7.		Fujifilm GFX 50S II	150 mm	104 mm	87 mm	900 g	440	Y	Sep 2021	3,999	amazon.com
8.		Fujifilm GFX 100 II	152 mm	117 mm	99 mm	1030 g	540	Y	Sep 2023	7,499	amazon.com
9.		Fujifilm GFX 100S	150 mm	104 mm	87 mm	900 g	460	Y	Jan 2021	5,999	amazon.com
10.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	1,899	ebay.com
11.		Fujifilm XP140	110 mm	71 mm	28 mm	207 g	240	Y	Feb 2019	229	ebay.com
12.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	8,995	ebay.com
13.		Hasselblad X2D 100C	149 mm	106 mm	75 mm	895 g	420	Y	Sep 2022	8,199	amazon.com
14.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	7,450	ebay.com
15.		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 manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The 645Z was launched at a somewhat lower price (by 15 percent) than the GFX 100, 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.

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 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. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to 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.

Both cameras under consideration feature a medium format sensor, but their sensors differ slightly in size. They nevertheless have the same format factor of 0.79. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.

With 101.8MP, the GFX 100 offers a higher resolution than the 645Z (51.1MP), but the GFX 100 has smaller individual pixels (pixel pitch of 3.76μm versus 5.30μm for the 645Z). However, the GFX 100 is a much more recent model (by 5 years and 1 month) than the 645Z, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels. Coming back to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

The resolution advantage of the Fujifilm GFX 100 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the GFX 100 for good quality output (200 dots per inch) amounts to 58.2 x 43.7 inches or 147.9 x 110.9 cm, for very good quality (250 dpi) 46.6 x 34.9 inches or 118.3 x 88.8 cm, and for excellent quality (300 dpi) 38.8 x 29.1 inches or 98.6 x 74 cm. The corresponding values for the Pentax 645Z are 41.3 x 31 inches or 104.9 x 78.6 cm for good quality, 33 x 24.8 inches or 83.9 x 62.9 cm for very good quality, and 27.5 x 20.6 inches or 69.9 x 52.4 cm for excellent quality prints.

The GFX 100 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Fujifilm GFX 100 has a native sensitivity range from ISO 100 to ISO 12800, which can be extended to ISO 50-102400. The corresponding ISO settings for the Pentax 645Z are ISO 100 to ISO 204800 (no boost).

In terms of underlying technology, the GFX 100 is build around a BSI-CMOS sensor, while the 645Z uses a CMOS imager. 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 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"). 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.		Fujifilm GFX 100	Medium Format	101.8	11648	8736	4K/30p	25.7	14.5	3227	99
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.		Fujifilm GFX 50R	Medium Format	51.1	8256	6192	1080/30p	25.7	14.4	3169	98
6.		Fujifilm GFX 50S	Medium Format	51.1	8256	6192	1080/30p	25.4	14.1	2977	96
7.		Fujifilm GFX 50S II	Medium Format	51.1	8256	6192	1080/30p	25.9	14.8	3456	100
8.		Fujifilm GFX 100 II	Medium Format	101.8	11648	8736	8K/30p	25.9	15.0	3651	101
9.		Fujifilm GFX 100S	Medium Format	101.8	11648	8736	4K/30p	25.8	14.7	3391	100
10.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
11.		Fujifilm XP140	1/2.3	15.9	4608	3456	4K/15p	20.7	12.2	1102	52
12.		Hasselblad X1D	Medium Format	51.3	8272	6200	1080/25p	26.2	14.8	4489	102
13.		Hasselblad X2D 100C	Medium Format	102.1	11656	8762	none	25.9	14.9	3550	101
14.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
15.		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 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 GFX 100 provides a higher video resolution than the 645Z. It can shoot video footage at 4K/30p, while the Pentax is limited to 1080/60i.

Feature comparison

Beyond 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 GFX 100 relies on live view and the rear LCD for framing. That said, the GFX 100 can be equipped with an optional viewfinder – the EVF-GFX2. The table below summarizes some of the other core capabilities of the Fujifilm GFX 100 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.		Fujifilm GFX 100	optional	Y	3.2 / 2360	full-flex	Y	1/4000s	5.0/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.		Fujifilm GFX 50R	3690	n	3.2 / 2360	tilting	Y	1/4000s	3.0/s	n	n
6.		Fujifilm GFX 50S	optional	Y	3.2 / 2360	full-flex	Y	1/4000s	3.0/s	n	n
7.		Fujifilm GFX 50S II	3690	Y	3.2 / 2360	full-flex	Y	1/4000s	3.0/s	n	Y
8.		Fujifilm GFX 100 II	9440	Y	3.2 / 2360	full-flex	Y	1/4000s	8.0/s	n	Y
9.		Fujifilm GFX 100S	3690	Y	3.2 / 2360	full-flex	Y	1/4000s	5.0/s	n	Y
10.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
11.		Fujifilm XP140	none	n	3.0 / 920	fixed	n	1/2000s	10.0/s	Y	Y
12.		Hasselblad X1D	2360	n	3.0 / 920	fixed	Y	1/2000s	2.3/s	n	n
13.		Hasselblad X2D 100C	5760	Y	3.6 / 2360	tilting	Y	1/4000s	3.3/s	n	Y
14.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
15.		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 GFX 100 and the 645Z is in-body image stabilization (IBIS). The GFX 100 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 reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the GFX 100 is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).

The Fujifilm GFX 100 and the Pentax 645Z both have 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 GFX 100 and the 645Z write their files to SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. The GFX 100 supports UHS-II cards (on both slots), while the 645Z can use UHS-I 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 Fujifilm GFX 100 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.		Fujifilm GFX 100	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
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.		Fujifilm GFX 50R	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
6.		Fujifilm GFX 50S	Y	stereo / mono	Y	Y	micro	3.0	Y	-	-
7.		Fujifilm GFX 50S II	Y	stereo / mono	Y	Y	micro	3.2	Y	-	-
8.		Fujifilm GFX 100 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
9.		Fujifilm GFX 100S	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
10.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
11.		Fujifilm XP140	-	mono / mono	-	-	micro	2.0	Y	-	Y
12.		Hasselblad X1D	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
13.		Hasselblad X2D 100C	Y	stereo / mono	-	-	-	3.2	Y	-	-
14.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
15.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-

It is notable that the GFX 100 has a headphone jack, which is not present on the 645Z This port makes it possible to attach external headphones and monitor the quality of sound during the recording process.

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

Both the GFX 100 and the 645Z have been discontinued, but can regularly be found used on ebay. The GFX 100 was replaced by the Fujifilm GFX 100 II, while the 645Z does not have a direct successor. Further information on the features and operation of the GFX 100 and 645Z can be found, respectively, in the Fujifilm GFX 100 Manual (free pdf) or the online Pentax 645Z Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Fujifilm GFX 100 or the Pentax 645Z – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Fujifilm GFX 100:

• More detail: Offers more megapixels (101.8 vs 51.1MP) with a 41% higher linear resolution.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• More detailed LCD: Has a higher resolution rear screen (2360k vs 1037k dots).
• More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
• Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
• Faster burst: Shoots at higher frequency (5 vs 3 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Less heavy: Is lighter (by 230g or 15 percent) and hence easier to carry around.
• More portrait friendly: Features an integrated vertical grip for easier portrait shooting.
• Longer lasting: Can take more shots (800 versus 650) on a single battery charge.
• Easier travel charging: Can be conveniently charged via its USB port.
• 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.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
• More modern: Reflects 5 years and 1 month of technical progress since the 645Z launch.

Advantages of the Pentax 645Z:

• Easier framing: Has an optical viewfinder for image composition and settings control.
• More compact: Is smaller (156x117mm vs 156x144mm) and will fit more readily into a bag.
• More affordable: Was released into a lower priced segment (15 percent cheaper at launch).
• More heavily discounted: Has been around for much longer (launched in April 2014).

If the number of relative strengths (bullet points above) is taken as a guide, the GFX 100 is the clear winner of the match-up (19 : 4 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 wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports 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 Fujifilm GFX 100 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 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 GFX 100 or the 645Z perform in practice. 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 where reviews by experts come in. 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.		Fujifilm GFX 100	4.5/5	+ +	4.8/5	90/100	5/5	4.5/5	May 2019	9,999	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.		Fujifilm GFX 50R	5/5	..	5/5	84/100	4.5/5	4.5/5	Sep 2018	4,499	ebay.com
6.		Fujifilm GFX 50S	..	..	4.5/5	85/100	5/5	4.5/5	Sep 2016	6,499	ebay.com
7.		Fujifilm GFX 50S II	5/5	..	5/5	87/100	..	5/5	Sep 2021	3,999	amazon.com
8.		Fujifilm GFX 100 II	5/5	+	5/5	..	..	4.5/5	Sep 2023	7,499	amazon.com
9.		Fujifilm GFX 100S	5/5	+ +	5/5	90/100	5/5	5/5	Jan 2021	5,999	amazon.com
10.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	1,899	ebay.com
11.		Fujifilm XP140	..	+	..	..	3.5/5	4/5	Feb 2019	229	ebay.com
12.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	8,995	ebay.com
13.		Hasselblad X2D 100C	4/5	..	5/5	..	..	..	Sep 2022	8,199	amazon.com
14.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	7,450	ebay.com
15.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Check GFX 100 offers at
ebay.com
Check 645Z offers at
ebay.com

Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

~

Check GFX 100 offers at
ebay.com
Check 645Z offers at
ebay.com

Did you notice an error on this page? If so, please get in touch, so that we can correct the information.