Fujifilm X-A2 vs Pentax 645D

The Fujifilm X-A2 and the Pentax 645D are two digital cameras that were revealed to the public, respectively, in January 2015 and March 2010. The X-A2 is a mirrorless interchangeable lens camera, while the 645D is a DSLR. The cameras are based on an APS-C (X-A2) and a medium format (645D) sensor. The Fujifilm has a resolution of 16 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 X-A2		Pentax 645D
Mirrorless system camera		Digital single lens reflex
Fujifilm X mount lenses		Pentax 645 mount lenses
16 MP – APS-C sensor		39.5 MP – Medium Format sensor
1080/30p Video		no Video
ISO 200-6,400 (100 - 25,600)		ISO 100-1,600
No viewfinder, LCD framing		Optical viewfinder
3.0" LCD – 920k dots		3.0" LCD – 921k dots
Tilting screen (no touchscreen)		Fixed screen (not touch-sensitive)
5.6 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
410 shots per battery charge		800 shots per battery charge
117 x 67 x 40 mm, 350 g		156 x 117 x 119 mm, 1480 g

Check X-A2 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 X-A2 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 physical size and weight of the Fujifilm X-A2 and the Pentax 645D 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.

The X-A2 can be obtained in three different colors (black, brown, white), 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 (133 percent) than the Fujifilm X-A2. Moreover, the 645D is substantially heavier (323 percent) than the X-A2. It is noteworthy in this context that the 645D is splash and dust-proof, while the X-A2 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 X-A2 gets 410 shots out of its Fujifilm NP-W126 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 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 X-A2	117 mm	67 mm	40 mm	350 g	410	n	Jan 2015	399	ebay.com
2.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
3.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
4.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
5.		Fujifilm X-A5	117 mm	68 mm	40 mm	361 g	450	n	Jan 2018	399	ebay.com
6.		Fujifilm X70	113 mm	64 mm	44 mm	340 g	330	n	Jan 2016	799	ebay.com
7.		Fujifilm X-A3	117 mm	67 mm	40 mm	339 g	410	n	Aug 2016	399	ebay.com
8.		Fujifilm X-A10	117 mm	67 mm	40 mm	331 g	410	n	Dec 2016	399	ebay.com
9.		Fujifilm X-E2S	129 mm	75 mm	37 mm	350 g	350	n	Jan 2016	699	ebay.com
10.		Fujifilm X-T10	118 mm	83 mm	41 mm	381 g	350	n	May 2015	799	ebay.com
11.		Fujifilm X-A1	117 mm	67 mm	39 mm	330 g	350	n	Sep 2013	399	ebay.com
12.		Fujifilm X-E2	129 mm	75 mm	37 mm	350 g	350	n	Oct 2013	999	ebay.com
13.		Fujifilm X-M1	117 mm	67 mm	39 mm	330 g	350	n	Jun 2013	699	ebay.com
14.		Fujifilm X-E1	129 mm	75 mm	38 mm	350 g	350	n	Sep 2012	999	ebay.com
15.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
16.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	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 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 X-A2 was launched at a markedly lower price (by 96 percent) than the 645D, 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 size of the sensor inside a digital camera is one of the key determinants of image quality. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and 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 tend to be associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Fujifilm X-A2 features an APS-C sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 295 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 X-A2 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 X-A2 (16MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 4.80μm for the X-A2) due to its larger sensor. However, the X-A2 is a much more recent model (by 4 years and 10 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 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 X-A2 are 24.5 x 16.3 inches or 62.2 x 41.5 cm for good quality, 19.6 x 13.1 inches or 49.7 x 33.2 cm for very good quality, and 16.3 x 10.9 inches or 41.5 x 27.6 cm for excellent quality prints.

The Fujifilm X-A2 has a native sensitivity range from ISO 200 to ISO 6400, which can be extended to ISO 100-25600. The corresponding ISO settings for the Pentax 645D are ISO 100 to ISO 1600 (no boost).

In terms of underlying technology, the X-A2 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.

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. 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 X-A2	APS-C	16.0	4896	3264	1080/30p	23.6	12.8	1515	79
2.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
3.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
4.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
5.		Fujifilm X-A5	APS-C	24.0	6000	4000	4K/15p	24.0	13.3	1800	82
6.		Fujifilm X70	APS-C	16.0	4896	3264	1080/60p	23.7	13.0	1608	80
7.		Fujifilm X-A3	APS-C	24.0	6000	4000	1080/60p	23.8	13.1	1664	81
8.		Fujifilm X-A10	APS-C	16.0	4896	3264	1080/30p	23.9	13.2	1691	81
9.		Fujifilm X-E2S	APS-C	16.0	4896	3264	1080/60p	23.7	13.0	1608	80
10.		Fujifilm X-T10	APS-C	16.0	4896	3264	1080/60p	23.7	12.9	1546	79
11.		Fujifilm X-A1	APS-C	16.0	4896	3264	1080/30p	23.4	12.6	1390	76
12.		Fujifilm X-E2	APS-C	16.0	4896	3264	1080/60p	23.4	12.6	1400	77
13.		Fujifilm X-M1	APS-C	16.0	4896	3264	1080/30p	23.4	12.6	1371	76
14.		Fujifilm X-E1	APS-C	16.0	4896	3264	1080/24p	23.2	12.4	1298	75
15.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
16.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
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 can also record movies. The X-A2 indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the X-A2 can use is 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the 645D has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the X-A2 relies on live view and the rear LCD for framing. The table below summarizes some of the other core capabilities of the Fujifilm X-A2 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 X-A2	none	n	3.0 / 920	tilting	n	1/4000s	5.6/s	Y	n
2.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
3.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
4.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
5.		Fujifilm X-A5	none	n	3.0 / 1040	tilting	Y	1/4000s	6.0/s	Y	n
6.		Fujifilm X70	optional	n	3.0 / 1040	tilting	Y	1/4000s	8.0/s	Y	n
7.		Fujifilm X-A3	none	n	3.0 / 1040	tilting	Y	1/4000s	6.0/s	Y	n
8.		Fujifilm X-A10	none	n	3.0 / 1040	tilting	n	1/4000s	6.0/s	Y	n
9.		Fujifilm X-E2S	2360	n	3.0 / 1040	fixed	n	1/4000s	7.0/s	Y	n
10.		Fujifilm X-T10	2360	n	3.0 / 920	tilting	n	1/4000s	8.0/s	Y	n
11.		Fujifilm X-A1	none	n	3.0 / 920	tilting	n	1/4000s	5.6/s	Y	n
12.		Fujifilm X-E2	2360	n	3.0 / 1040	fixed	n	1/4000s	7.0/s	Y	n
13.		Fujifilm X-M1	none	n	3.0 / 920	tilting	n	1/4000s	5.6/s	Y	n
14.		Fujifilm X-E1	2360	n	2.8 / 460	fixed	n	1/4000s	6.0/s	Y	n
15.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
16.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
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 X-A2 has one, while the 645D does not. While the built-in flash of the X-A2 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 X-A2 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 X-A2 only has one slot. The X-A2 supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the 645D 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 Fujifilm X-A2 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 X-A2	Y	stereo / mono	-	-	mini	2.0	Y	-	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
4.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
5.		Fujifilm X-A5	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
6.		Fujifilm X70	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
7.		Fujifilm X-A3	Y	stereo / mono	-	-	micro	2.0	Y	-	-
8.		Fujifilm X-A10	-	stereo / mono	-	-	micro	2.0	Y	-	-
9.		Fujifilm X-E2S	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
10.		Fujifilm X-T10	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
11.		Fujifilm X-A1	Y	stereo / mono	-	-	mini	2.0	Y	-	-
12.		Fujifilm X-E2	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
13.		Fujifilm X-M1	Y	stereo / mono	-	-	mini	2.0	Y	-	-
14.		Fujifilm X-E1	Y	stereo / mono	Y	-	mini	2.0	-	-	-
15.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
16.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
17.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

It is notable that the X-A2 offers wifi support, while the 645D does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Studio photographers will appreciate that the Pentax 645D (unlike the X-A2) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the X-A2 and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the X-A2 was followed by the Fujifilm X-A3. Further information on the features and operation of the X-A2 and 645D can be found, respectively, in the Fujifilm X-A2 Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So how do things add up? Is the Fujifilm X-A2 better than the Pentax 645D or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Fujifilm X-A2:

• 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 1080/30p movies.
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster burst: Shoots at higher frequency (5.6 vs 1.1 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (117x67mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 1130g or 76 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.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More affordable: Was introduced into a lower priced category (96 percent cheaper at launch).
• More modern: Reflects 4 years and 10 months of technical progress since the 645D launch.

Advantages of the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 16MP), which boosts linear resolution by 54%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• 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.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Gets more shots (800 versus 410) 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 X-A2 emerges as the winner of the contest (13 : 10 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 X-A2 and the Pentax 645D 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 says little about, for example, the shooting experience and imaging performance of the X-A2 and the 645D in practical situations. 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.		Fujifilm X-A2	4/5	..	..	..	4.5/5	4.5/5	Jan 2015	399	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
3.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
4.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
5.		Fujifilm X-A5	..	+	4.1/5	..	4/5	3.5/5	Jan 2018	399	ebay.com
6.		Fujifilm X70	4.5/5	..	..	76/100	4.5/5	4.5/5	Jan 2016	799	ebay.com
7.		Fujifilm X-A3	..	..	..	74/100	4.5/5	4/5	Aug 2016	399	ebay.com
8.		Fujifilm X-A10	..	..	..	..	4/5	4/5	Dec 2016	399	ebay.com
9.		Fujifilm X-E2S	4.5/5	..	..	77/100	4.5/5	4.5/5	Jan 2016	699	ebay.com
10.		Fujifilm X-T10	4.5/5	+ +	..	80/100	5/5	5/5	May 2015	799	ebay.com
11.		Fujifilm X-A1	..	..	..	..	4.5/5	4.5/5	Sep 2013	399	ebay.com
12.		Fujifilm X-E2	4/5	..	..	80/100	4.5/5	5/5	Oct 2013	999	ebay.com
13.		Fujifilm X-M1	3/5	+	..	77/100	4.5/5	4.5/5	Jun 2013	699	ebay.com
14.		Fujifilm X-E1	4/5	+ +	..	79/100	4.5/5	4.5/5	Sep 2012	999	ebay.com
15.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
16.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	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 review scores listed above should be treated with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. Thus, a score needs to be put into the context of the launch date and the launch price 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, 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

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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