Fujifilm X20 vs Pentax 645D

The Fujifilm X20 and the Pentax 645D are two digital cameras that were officially introduced, respectively, in January 2013 and March 2010. The X20 is a fixed lens compact, while the 645D is a DSLR. The cameras are based on a 2/3 (X20) and a medium format (645D) sensor. The Fujifilm has a resolution of 12 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 X20		Pentax 645D
Fixed lens compact camera		Digital single lens reflex
28-112mm f/2.0-2.8		Pentax 645 mount lenses
12 MP – Two Thirds sensor		39.5 MP – Medium Format sensor
1080/60p Video		no Video
ISO 100-12,800		ISO 100-1,600
Optical viewfinder		Optical viewfinder
2.8" LCD – 460k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
12 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
270 shots per battery charge		800 shots per battery charge
117 x 70 x 57 mm, 353 g		156 x 117 x 119 mm, 1480 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Fujifilm X20 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

An illustration of the physical size and weight of the Fujifilm X20 and the Pentax 645D is provided 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.

The X20 can be obtained in two different colors (black, silver), while the 645D 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 645D is considerably larger (123 percent) than the Fujifilm X20. It is noteworthy in this context that the 645D is splash and dust-proof, while the X20 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the X20 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 X20 gets 270 shots out of its Fujifilm NP-50 battery, while the 645D can take 800 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 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.		Fujifilm X20	117 mm	70 mm	57 mm	353 g	270	n	Jan 2013	599	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 G7 X	103 mm	60 mm	40 mm	304 g	210	n	Sep 2014	699	ebay.com
6.		Canon G15	107 mm	76 mm	40 mm	352 g	350	n	Sep 2012	499	ebay.com
7.		Canon G16	109 mm	76 mm	40 mm	356 g	360	n	Aug 2013	549	ebay.com
8.		Fujifilm X10	117 mm	70 mm	57 mm	350 g	270	n	Sep 2011	599	ebay.com
9.		Fujifilm X30	119 mm	72 mm	60 mm	423 g	470	n	Aug 2014	599	ebay.com
10.		Fujifilm XQ1	100 mm	59 mm	33 mm	206 g	240	n	Oct 2013	499	ebay.com
11.		Leica D-LUX 6	111 mm	68 mm	46 mm	298 g	330	n	Sep 2012	699	ebay.com
12.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
13.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
14.		Nikon P7800	119 mm	78 mm	50 mm	399 g	350	n	Sep 2013	549	ebay.com
15.		Olympus Stylus 1	116 mm	87 mm	57 mm	402 g	410	n	Oct 2013	699	ebay.com
16.		Panasonic LX7	111 mm	68 mm	46 mm	298 g	330	n	Jul 2012	499	ebay.com
17.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	8,499	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The X20 was launched at a lower price than the 645D, despite having a lens built in. 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 size of the imaging sensor is a crucial determinant 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. 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Fujifilm X20 features a 2/3 sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 2403 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 3.9 and 0.79. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.

With 39.5MP, the 645D offers a higher resolution than the X20 (12MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 2.20μm for the X20) due to its larger sensor. However, the X20 is a much more recent model (by 2 years and 9 months) than the 645D, and its sensor will 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 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 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 X20 are 20 x 15 inches or 50.8 x 38.1 cm for good quality, 16 x 12 inches or 40.6 x 30.5 cm for very good quality, and 13.3 x 10 inches or 33.9 x 25.4 cm for excellent quality prints.

The X20 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Fujifilm X20 has a native sensitivity range from ISO 100 to ISO 12800. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).

In terms of underlying technology, the X20 is build around a CMOS sensor, while the 645D uses a CCD imager. The X20 uses Fujifilm's X-Trans layout of photosites, while the 645D employs the more common Bayer array.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-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 X20	2/3	12.0	4000	3000	1080/60p	20.1	10.9	-462	46
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 G7 X	1-inch	20.0	5472	3648	1080/60p	23.0	12.7	556	71
6.		Canon G15	1/1.7	12.0	4000	3000	1080/24p	19.9	11.5	165	46
7.		Canon G16	1/1.7	12.0	4000	3000	1080/60p	21.0	11.7	230	54
8.		Fujifilm X10	2/3	12.0	4000	3000	1080/30p	20.5	11.3	245	50
9.		Fujifilm X30	2/3	12.0	4000	3000	1080/60p	20.4	11.2	-312	49
10.		Fujifilm XQ1	2/3	12.0	4000	3000	1080/60p	20.3	11.0	-390	47
11.		Leica D-LUX 6	1/1.7	10.0	3648	2736	1080/60p	19.8	10.8	-303	43
12.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
13.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
14.		Nikon P7800	1/1.7	12.0	4000	3000	1080/30p	21.2	11.7	200	54
15.		Olympus Stylus 1	1/1.7	11.8	3968	2976	1080/30p	20.7	11.6	179	51
16.		Panasonic LX7	1/1.7	10.0	3648	2736	1080/60p	20.7	11.7	147	50
17.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
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 also of capturing video footage. The X20 indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the X20 can use is 1080/60p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The X20 and the 645D 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 adjacent table lists some of the other core features of the Fujifilm X20 and Pentax 645D along with similar information for a selection of comparators.

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 X20	optical	n	2.8 / 460	fixed	n	1/4000s	12.0/s	Y	Y
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 G7 X	none	n	3.0 / 1040	tilting	Y	1/2000s	6.5/s	Y	Y
6.		Canon G15	optical	n	3.0 / 922	fixed	n	1/4000s	2.1/s	Y	Y
7.		Canon G16	optical	n	3.0 / 922	fixed	n	1/4000s	2.2/s	Y	Y
8.		Fujifilm X10	optical	n	2.8 / 460	fixed	n	1/4000s	10.0/s	Y	Y
9.		Fujifilm X30	2360	n	3.0 / 920	tilting	n	1/4000s	12.0/s	Y	Y
10.		Fujifilm XQ1	none	n	3.0 / 920	fixed	n	1/4000s	12.0/s	Y	Y
11.		Leica D-LUX 6	optional	n	3.0 / 920	fixed	n	1/4000s	11.0/s	Y	Y
12.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
13.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
14.		Nikon P7800	921	n	3.0 / 921	swivel	n	1/4000s	8.0/s	Y	Y
15.		Olympus Stylus 1	1440	n	3.0 / 1040	tilting	Y	1/2000s	7.0/s	Y	Y
16.		Panasonic LX7	optional	n	3.0 / 920	fixed	n	1/4000s	11.0/s	Y	Y
17.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/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 X20 has one, while the 645D does not. While the built-in flash of the X20 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 X20 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 X20 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 X20 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 X20	Y	stereo / mono	-	-	micro	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 G7 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
6.		Canon G15	Y	stereo / mono	-	-	mini	2.0	-	-	-
7.		Canon G16	Y	stereo / mono	-	-	mini	2.0	Y	-	-
8.		Fujifilm X10	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Fujifilm X30	Y	stereo / mono	-	-	micro	2.0	Y	-	-
10.		Fujifilm XQ1	-	stereo / mono	-	-	micro	2.0	Y	-	-
11.		Leica D-LUX 6	Y	stereo / mono	-	-	mini	2.0	-	-	-
12.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
13.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
14.		Nikon P7800	Y	stereo / mono	Y	-	mini	2.0	-	-	-
15.		Olympus Stylus 1	Y	stereo / mono	-	-	micro	2.0	Y	-	-
16.		Panasonic LX7	Y	stereo / mono	-	-	mini	2.0	-	-	-
17.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

Studio photographers will appreciate that the Pentax 645D (unlike the X20) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the X20 and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the X20 was followed by the Fujifilm X30. Further information on the features and operation of the X20 and 645D can be found, respectively, in the Fujifilm X20 Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So what conclusions can be drawn? Is there a clear favorite between the Fujifilm X20 and the Pentax 645D? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer the Fujifilm X20:

• Broader imaging potential: Can record not only still images but also 1080/60p movies.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Faster burst: Shoots at higher frequency (12 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 (117x70mm 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).
• 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 at a lower price, despite coming with a built-in lens.
• More modern: Reflects 2 years and 9 months of technical progress since the 645D launch.

Arguments in favor of the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 12MP), which boosts linear resolution by 82%.
• Better image quality: Features bigger pixels on a larger sensor for higher quality imaging.
• Richer colors: The pixel size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger pixels capture a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger pixels means good image quality even under poor lighting.
• 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 270) 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 around for much longer (launched in March 2010).

If the number of relative strengths (bullet points above) is taken as a guide, the 645D is the clear winner of the contest (15 : 10 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 X20 and the Pentax 645D place the cameras among the top in their class? Find out in the latest Best Travel-Zoom 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 incomplete and does no justice, for example, to the way the X20 or the 645D perform in practice. 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 where reviews by experts come in. 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.		Fujifilm X20	4/5	+ +	..	77/100	4.5/5	5/5	Jan 2013	599	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 G7 X	4/5	+ +	..	77/100	4.5/5	4.5/5	Sep 2014	699	ebay.com
6.		Canon G15	4/5	+	..	76/100	4.5/5	4.5/5	Sep 2012	499	ebay.com
7.		Canon G16	4/5	+	..	..	4.5/5	4.5/5	Aug 2013	549	ebay.com
8.		Fujifilm X10	..	..	..	76/100	4/5	4.5/5	Sep 2011	599	ebay.com
9.		Fujifilm X30	4/5	..	..	76/100	4.5/5	4.5/5	Aug 2014	599	ebay.com
10.		Fujifilm XQ1	..	..	..	..	4.5/5	4.5/5	Oct 2013	499	ebay.com
11.		Leica D-LUX 6	..	..	..	..	4/5	4/5	Sep 2012	699	ebay.com
12.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
13.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
14.		Nikon P7800	3/5	..	..	..	4/5	4.5/5	Sep 2013	549	ebay.com
15.		Olympus Stylus 1	..	+ +	..	..	4.5/5	4.5/5	Oct 2013	699	ebay.com
16.		Panasonic LX7	3/5	+ +	..	75/100	4/5	4.5/5	Jul 2012	499	ebay.com
17.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, 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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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 your choice using the following search menu. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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