Fujifilm X100 vs Pentax 645D

The Fujifilm FinePix X100 and the Pentax 645D are two digital cameras that were announced, respectively, in September 2010 and March 2010. The X100 is a fixed lens compact, while the 645D is a DSLR. The cameras are based on an APS-C (X100) and a medium format (645D) sensor. The Fujifilm has a resolution of 12.2 megapixels, whereas the Pentax provides 39.5 MP.

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

Headline Specifications

Fujifilm X100		Pentax 645D
Fixed lens compact camera		Digital single lens reflex
35mm f/2.0		Pentax 645 mount lenses
12.2 MP – APS-C sensor		39.5 MP – Medium Format sensor
720/30p Video		no Video
ISO 200-6,400 (100 - 12,800)		ISO 100-1,600
Electronic viewfinder (1440k dots)		Optical viewfinder
2.8" LCD – 460k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
5 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
300 shots per battery charge		800 shots per battery charge
126 x 75 x 54 mm, 445 g		156 x 117 x 119 mm, 1480 g

Check X100 offers at
ebay.com
Check 645D offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Fujifilm FinePix X100 and the Pentax 645D? 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 Fujifilm X100 and the Pentax 645D. 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 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 645D is considerably larger (93 percent) than the Fujifilm X100. It is noteworthy in this context that the 645D is splash and dust-proof, while the X100 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the X100 has a lens built in, whereas the 645D is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.

Concerning battery life, the X100 gets 300 shots out of its Fujifilm NP-95 battery, while the 645D can take 800 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. 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 (USD)	Street Price
1.		Fujifilm X100	126 mm	75 mm	54 mm	445 g	300	n	Sep 2010	1,199	ebay.com
2.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
3.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
4.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
5.		Canon G1 X	117 mm	81 mm	65 mm	534 g	250	n	Jan 2012	799	ebay.com
6.		Fujifilm X30	119 mm	72 mm	60 mm	423 g	470	n	Aug 2014	599	ebay.com
7.		Fujifilm X100S	127 mm	74 mm	54 mm	445 g	330	n	Jan 2013	1,299	ebay.com
8.		Fujifilm X100T	127 mm	74 mm	52 mm	440 g	330	n	Sep 2014	1,299	ebay.com
9.		Fujifilm X100F	127 mm	75 mm	52 mm	469 g	390	n	Jan 2017	1,299	ebay.com
10.		Leica D-LUX Typ 109	118 mm	66 mm	55 mm	405 g	300	n	Sep 2014	1,195	ebay.com
11.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
12.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
13.		Nikon D3000	126 mm	97 mm	64 mm	536 g	500	n	Jul 2009	599	ebay.com
14.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	599	ebay.com
15.		Panasonic LX100	115 mm	66 mm	55 mm	393 g	300	n	Sep 2014	899	ebay.com
16.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	8,499	ebay.com
17.		Sony NEX-7	120 mm	67 mm	43 mm	400 g	430	n	Aug 2011	1,349	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The X100 was launched at a lower price than the 645D, despite having a lens built in. 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. 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Fujifilm X100 features an APS-C sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 289 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 0.79. The sensor in the X100 has a native 3:2 aspect ratio, while the one in the 645D offers a 4:3 aspect.

With 39.5MP, the 645D offers a higher resolution than the X100 (12.2MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 5.53μm for the X100) due to its larger sensor. However, the X100 is a somewhat more recent model (by 6 months) than the 645D, and its sensor might 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 645D has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax 645D implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 645D for good quality output (200 dots per inch) amounts to 36.3 x 27.2 inches or 92.3 x 69.1 cm, for very good quality (250 dpi) 29.1 x 21.8 inches or 73.8 x 55.3 cm, and for excellent quality (300 dpi) 24.2 x 18.1 inches or 61.5 x 46.1 cm. The corresponding values for the Fujifilm X100 are 21.4 x 14.2 inches or 54.5 x 36.2 cm for good quality, 17.2 x 11.4 inches or 43.6 x 28.9 cm for very good quality, and 14.3 x 9.5 inches or 36.3 x 24.1 cm for excellent quality prints.

The Fujifilm FinePix X100 has a native sensitivity range from ISO 200 to ISO 6400, which can be extended to ISO 100-12800. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).

In terms of underlying technology, the X100 is build around a CMOS sensor, while the 645D uses a CCD 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.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 645D has a markedly higher DXO score than the X100 (overall score 9 points higher), which will translate into better image quality. The advantage is based on 1.7 bits higher color depth, 0.2 EV in additional dynamic range, and 0.3 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.		Fujifilm X100	APS-C	12.2	4288	2848	720/30p	22.9	12.4	1001	73
2.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
3.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
4.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
5.		Canon G1 X	1.5-inch	14.2	4352	3264	1080/24p	21.7	10.8	644	60
6.		Fujifilm X30	2/3	12.0	4000	3000	1080/60p	20.4	11.2	-312	49
7.		Fujifilm X100S	APS-C	16.0	4896	3264	1080/60p	23.3	12.5	1329	75
8.		Fujifilm X100T	APS-C	16.0	4896	3264	1080/60p	23.6	12.8	1483	78
9.		Fujifilm X100F	APS-C	24.0	6000	4000	1080/60p	23.9	13.2	1704	81
10.		Leica D-LUX Typ 109	Four Thirds	12.7	4112	3088	4K/30p	22.4	12.1	607	67
11.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
12.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
13.		Nikon D3000	APS-C	10.0	3872	2592	none	22.3	11.1	563	62
14.		Nikon D3100	APS-C	14.2	4608	3072	1080/24p	22.5	11.3	919	67
15.		Panasonic LX100	Four Thirds	12.7	4112	3088	4K/30p	22.3	12.5	553	67
16.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
17.		Sony NEX-7	APS-C	24.0	6000	4000	1080/60i	24.1	13.4	1016	81
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. The X100 indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the X100 can use is 720/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the X100 has an electronic viewfinder (1440k dots), while the 645D has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The viewfinder in the X100 offers a wider field of view (100%) than the one in the 645D (98%), so that a larger proportion of the captured image is visible in the finder. On the other hand, the viewfinder of the 645D has a higher magnification (0.78x vs 0.50x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Fujifilm X100 and Pentax 645D 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 X100	1440	n	2.8 / 460	fixed	n	1/4000s	5.0/s	Y	n
2.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
3.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
4.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
5.		Canon G1 X	optical	n	3.0 / 922	swivel	n	1/4000s	1.9/s	Y	Y
6.		Fujifilm X30	2360	n	3.0 / 920	tilting	n	1/4000s	12.0/s	Y	Y
7.		Fujifilm X100S	2360	n	2.8 / 460	fixed	n	1/4000s	6.0/s	Y	n
8.		Fujifilm X100T	2360	n	3.0 / 1040	fixed	n	1/4000s	6.0/s	Y	n
9.		Fujifilm X100F	2360	n	3.0 / 1040	fixed	n	1/4000s	8.0/s	Y	n
10.		Leica D-LUX Typ 109	2764	n	3.0 / 921	fixed	n	1/4000s	11.0/s	n	Y
11.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
12.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
13.		Nikon D3000	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
14.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
15.		Panasonic LX100	2764	n	3.0 / 921	fixed	n	1/4000s	11.0/s	n	Y
16.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
17.		Sony NEX-7	2359	n	3.0 / 921	tilting	n	1/4000s	10.0/s	Y	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 X100 has one, while the 645D does not. While the built-in flash of the X100 is not very powerful, it can at times be useful as a fill-in light.

The Pentax 645D 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 X100 and the 645D write their files to SDXC cards. The 645D features dual card slots, which can be very useful in case a memory card fails. In contrast, the X100 only has one slot.

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 FinePix X100 and Pentax 645D 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 X100	Y	stereo / -	-	-	mini	2.0	-	-	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
4.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
5.		Canon G1 X	Y	stereo / mono	-	-	mini	2.0	-	-	-
6.		Fujifilm X30	Y	stereo / mono	-	-	micro	2.0	Y	-	-
7.		Fujifilm X100S	Y	stereo / mono	-	-	micro	2.0	-	-	-
8.		Fujifilm X100T	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
9.		Fujifilm X100F	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
10.		Leica D-LUX Typ 109	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
11.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
12.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
13.		Nikon D3000	Y	- / -	-	-	-	2.0	-	-	-
14.		Nikon D3100	Y	mono / mono	-	-	mini	2.0	-	-	-
15.		Panasonic LX100	Y	stereo / mono	-	-	micro	2.0	Y	Y	-
16.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-
17.		Sony NEX-7	Y	stereo / mono	Y	-	mini	2.0	-	-	-

Studio photographers will appreciate that the Pentax 645D (unlike the X100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the X100 and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the X100 was followed by the Fujifilm X100S. Further information on the features and operation of the X100 and 645D can be found, respectively, in the Fujifilm X100 Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Fujifilm X100 or the Pentax 645D – 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.

Advantages of the Fujifilm FinePix X100:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Broader imaging potential: Can record not only still images but also 720/30p movies.
• More framing info: Has an electronic viewfinder that displays shooting data.
• More complete view: Has a viewfinder with a larger field of view (100% vs 98%).
• Faster burst: Shoots at higher frequency (5 vs 1.1 flaps/sec) to capture the decisive moment.
• Ready to shoot: Comes with a built-in lens, while the 645D requires a separate lens.
• More compact: Is smaller (126x75mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter even though it comes with a built-in lens (unlike the 645D).
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More modern: Is somewhat more recent (announced 6 months after the 645D).

Arguments in favor of the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 12.2MP), which boosts linear resolution by 76%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Scores markedly higher (9 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (1.7 bits more color depth).
• Better low-light sensitivity: Can shoot in dim conditions (0.3 stops ISO advantage).
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.50x).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• Larger screen: Has a bigger rear LCD (3.0" vs 2.8") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 460k dots).
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More flexible: Makes it possible to change lenses and thus to use specialty optics.
• Longer lasting: Gets more shots (800 versus 300) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• 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 heavily discounted: Has been on the market for longer (launched in March 2010).

If the count of relative strengths (bullet points above) is taken as a measure, the 645D is the clear winner of the contest (17 : 11 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 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 Fujifilm X100 and the Pentax 645D place the cameras among the top in their class? Find out in the latest Best Prime Lens Compact 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 X100 or the 645D 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 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.		Fujifilm X100	3/5	..	..	75/100	4/5	5/5	Sep 2010	1,199	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
3.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
4.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
5.		Canon G1 X	5/5	+	..	76/100	4/5	4.5/5	Jan 2012	799	ebay.com
6.		Fujifilm X30	4/5	..	..	76/100	4.5/5	4.5/5	Aug 2014	599	ebay.com
7.		Fujifilm X100S	5/5	+ +	..	81/100	4.5/5	5/5	Jan 2013	1,299	ebay.com
8.		Fujifilm X100T	5/5	+	..	81/100	4.5/5	5/5	Sep 2014	1,299	ebay.com
9.		Fujifilm X100F	5/5	+	3.9/5	83/100	4.5/5	4.5/5	Jan 2017	1,299	ebay.com
10.		Leica D-LUX Typ 109	..	..	..	..	4.5/5	4.5/5	Sep 2014	1,195	ebay.com
11.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
12.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
13.		Nikon D3000	..	+	..	72/100	4/5	4.5/5	Jul 2009	599	ebay.com
14.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	599	ebay.com
15.		Panasonic LX100	5/5	+ +	..	85/100	5/5	5/5	Sep 2014	899	ebay.com
16.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	ebay.com
17.		Sony NEX-7	5/5	+ +	..	81/100	4.5/5	5/5	Aug 2011	1,349	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. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date 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

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