Fujifilm X-T4 vs Pentax K-3 III

The Fujifilm X-T4 and the Pentax K-3 III are two enthusiast cameras that were announced, respectively, in February 2020 and March 2021. The X-T4 is a mirrorless interchangeable lens camera, while the K-3 III is a DSLR. Both cameras are equipped with an APS-C sensor. The Fujifilm has a resolution of 26 megapixels, whereas the Pentax provides 25.6 MP.

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

Headline Specifications

Fujifilm X-T4		Pentax K-3 III
Mirrorless system camera		Digital single lens reflex
Fujifilm X mount lenses		Pentax K mount lenses
26 MP – APS-C sensor		25.6 MP – APS-C sensor
4K/60p Video		4K/30p Video
ISO 160-12,800 (80 - 51,200)		ISO 100-160,000
Electronic viewfinder (3690k dots)		Optical viewfinder
3.0" LCD – 1620k dots		3.2" LCD – 1620k dots
Swivel touchscreen		Fixed touchscreen
15 shutter flaps per second		12 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
500 shots per battery charge		800 shots per battery charge
135 x 93 x 64 mm, 607 g		135 x 104 x 74 mm, 820 g

Check X-T4 offers at
ebay.com
Check K-3 III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Fujifilm X-T4 and the Pentax K-3 III? 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 X-T4 and the Pentax K-3 III. 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 dimensions are rounded to the nearest millimeter.

Both cameras are available in two different colors (black, silver).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-3 III is notably larger (12 percent) than the Fujifilm X-T4. Moreover, the K-3 III is substantially heavier (35 percent) than the X-T4. 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 X-T4 gets 500 shots out of its Fujifilm NP-W235 battery, while the K-3 III can take 800 images on a single charge of its Pentax D-LI90 power pack. The power pack in the X-T4 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. 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-T4	135 mm	93 mm	64 mm	607 g	500	Y	Feb 2020	1,699	ebay.com
2.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
3.		Fujifilm X-H2S	136 mm	93 mm	85 mm	660 g	580	Y	May 2022	2,499	amazon.com
4.		Fujifilm X-H2	136 mm	93 mm	85 mm	660 g	680	Y	Sep 2022	1,999	amazon.com
5.		Fujifilm X-T5	130 mm	91 mm	64 mm	557 g	580	Y	Nov 2022	1,699	amazon.com
6.		Fujifilm X-Pro3	141 mm	83 mm	46 mm	497 g	440	Y	Oct 2019	1,799	amazon.com
7.		Fujifilm X-T3	133 mm	93 mm	59 mm	539 g	390	Y	Sep 2018	1,499	ebay.com
8.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	1,899	ebay.com
9.		Fujifilm X-Pro2	141 mm	83 mm	46 mm	495 g	350	Y	Jan 2016	1,699	ebay.com
10.		Fujifilm X-T2	133 mm	92 mm	49 mm	507 g	340	Y	Jul 2016	1,599	ebay.com
11.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
12.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
13.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
14.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
15.		Sony A6600	120 mm	67 mm	69 mm	503 g	810	Y	Aug 2019	1,399	amazon.com
16.		Sony A77	143 mm	104 mm	81 mm	732 g	470	Y	Aug 2011	1,399	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 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-T4 was launched at a somewhat lower price (by 15 percent) than the K-3 III, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

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. 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.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the K-3 III is 2 percent smaller. They nevertheless have the same format factor of 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 26MP, the X-T4 offers a slightly higher resolution than the K-3 III (25.6MP), but the X-T4 nevertheless has the same individual pixel size (pixel pitch of 3.76μm) as the K-3 III due to its larger sensor. Moreover, the K-3 III is a somewhat more recent model (by 1 year and 1 month) than the X-T4, and its sensor might have benefitted from technological advances during this time that further 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 X-T4 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

Unlike the X-T4, the K-3 III has the capacity to capture high quality composite images (YESMP) by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

The Fujifilm X-T4 has a native sensitivity range from ISO 160 to ISO 12800, which can be extended to ISO 80-51200. The corresponding ISO settings for the Pentax K-3 III are ISO 100 to ISO 160000 (no boost).

In terms of underlying technology, the X-T4 is build around a BSI-CMOS sensor, while the K-3 III uses a CMOS imager. The X-T4 uses Fujifilm's X-Trans layout of photosites, while the K-3 III employs the more common Bayer array.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 X-T4	APS-C	26.0	6240	4160	4K/60p	24.1	13.6	1995	84
2.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
3.		Fujifilm X-H2S	APS-C	26.0	6240	4160	6.2k/30p	24.3	13.9	2224	86
4.		Fujifilm X-H2	APS-C	39.8	7728	5152	8k/30p	24.3	13.9	2249	86
5.		Fujifilm X-T5	APS-C	39.8	7728	5152	6.2k/30p	24.3	13.9	2264	86
6.		Fujifilm X-Pro3	APS-C	26.0	6240	4160	4K/30p	24.1	13.6	1968	84
7.		Fujifilm X-T3	APS-C	26.0	6240	4160	4K/60p	24.0	13.4	1853	83
8.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
9.		Fujifilm X-Pro2	APS-C	24.0	6000	4000	1080/60p	23.7	13.0	1608	80
10.		Fujifilm X-T2	APS-C	24.0	6000	4000	4K/30p	23.8	13.1	1653	81
11.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
12.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
13.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
14.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
15.		Sony A6600	APS-C	24.0	6000	4000	4K/30p	23.8	13.4	1497	82
16.		Sony A77	APS-C	24.0	6000	4000	1080/60p	24.0	13.2	801	78
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 have a sensor with sufficiently fast read-out times for moving pictures, but the X-T4 provides a higher frame rate than the K-3 III. It can shoot video footage at 4K/60p, while the Pentax is limited to 4K/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the X-T4 has an electronic viewfinder (3690k dots), while the K-3 III 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 viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the X-T4 has a higher magnification than the one of the K-3 III (0.75x vs 0.70x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The following table reports on some other key feature differences and similarities of the Fujifilm X-T4, the Pentax K-3 III, and comparable 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-T4	3690	n	3.0 / 1620	swivel	Y	1/8000s	15.0/s	n	Y
2.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
3.		Fujifilm X-H2S	5760	Y	3.0 / 1620	swivel	Y	1/8000s	15.0/s	n	Y
4.		Fujifilm X-H2	5760	Y	3.0 / 1620	swivel	Y	1/8000s	15.0/s	n	Y
5.		Fujifilm X-T5	3690	n	3.0 / 1840	full-flex	Y	1/8000s	15.0/s	n	Y
6.		Fujifilm X-Pro3	3690	n	3.0 / 1620	tilting	Y	1/8000s	8.0/s	n	n
7.		Fujifilm X-T3	3690	n	3.0 / 1040	full-flex	Y	1/8000s	11.0/s	n	n
8.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
9.		Fujifilm X-Pro2	2360	n	3.0 / 1620	fixed	n	1/8000s	8.0/s	n	n
10.		Fujifilm X-T2	2360	n	3.0 / 1040	full-flex	n	1/8000s	8.0/s	n	n
11.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
12.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
13.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
14.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
15.		Sony A6600	2359	n	3.0 / 922	tilting	Y	1/4000s	11.0/s	n	Y
16.		Sony A77	2359	Y	3.0 / 921	full-flex	n	1/8000s	12.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the K-3 III, but is missing on the X-T4 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

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 X-T4 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 X-T4 and the Pentax K-3 III 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 X-T4 and the K-3 III write their files to SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. However, while the X-T4 supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s) on both slots, the K-3 III supports UHS-II only on its first slot and UHS-I (data transfer speed up to 104 MB/s) on the second one.

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-T4 and Pentax K-3 III 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-T4	Y	stereo / mono	Y	-	micro	3.1	Y	-	Y
2.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
3.		Fujifilm X-H2S	Y	stereo / mono	Y	Y	full	3.0	Y	-	Y
4.		Fujifilm X-H2	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
5.		Fujifilm X-T5	Y	stereo / mono	Y	-	micro	3.2	Y	-	Y
6.		Fujifilm X-Pro3	Y	stereo / mono	Y	-	-	3.1	Y	-	Y
7.		Fujifilm X-T3	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
8.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
9.		Fujifilm X-Pro2	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
10.		Fujifilm X-T2	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
11.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
12.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
13.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
14.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
15.		Sony A6600	Y	stereo / mono	Y	Y	YES	2.0	Y	Y	Y
16.		Sony A77	Y	stereo / mono	Y	-	mini	2.0	-	-	-

It is notable that the K-3 III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The X-T4 lacks such a headphone port.

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

Travel and landscape photographers will find it useful that the K-3 III has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

The K-3 III is a recent model that features in the current product line-up of Pentax. In contrast, the X-T4 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the X-T4 was succeeded by the Fujifilm X-T5. Further information on the features and operation of the X-T4 and K-3 III can be found, respectively, in the Fujifilm X-T4 Manual (free pdf) or the online Pentax K-3 III Manual.

Review summary

So how do things add up? Is the Fujifilm X-T4 better than the Pentax K-3 III or vice versa? The listing below highlights the relative strengths of the two models.

Arguments in favor of the Fujifilm X-T4:

• Better video: Provides higher movie framerates (4K/60p versus 4K/30p).
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• More framing info: Has an electronic viewfinder that displays shooting data.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.75x vs 0.70x).
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster burst: Shoots at higher frequency (15 vs 12 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• More compact: Is smaller (135x93mm vs 135x104mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 213g or 26 percent) and hence easier to carry around.
• Easier travel charging: Can be conveniently charged via its USB port.
• More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
• More affordable: Was introduced into a lower priced segment (15 percent cheaper at launch).
• More heavily discounted: Has been on the market for longer (launched in February 2020).

Reasons to prefer the Pentax K-3 III:

• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• 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.
• Longer lasting: Gets more shots (800 versus 500) out of a single battery charge.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 3.1).
• More modern: Was introduced somewhat (1 year and 1 month) more recently.

If the count of individual advantages (bullet points above) is taken as a guide, the X-T4 is the clear winner of the match-up (14 : 9 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 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 X-T4 and the Pentax K-3 III 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 the spec-sheets of cameras can offer a general idea of their imaging potential, it says little about, for example, the shooting experience and imaging performance of the X-T4 and the K-3 III in practical situations. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.

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.		Fujifilm X-T4	5/5	+ +	5/5	88/100	5/5	5/5	Feb 2020	1,699	ebay.com
2.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
3.		Fujifilm X-H2S	5/5	+	5/5	90/100	5/5	5/5	May 2022	2,499	amazon.com
4.		Fujifilm X-H2	5/5	+ +	5/5	89/100	5/5	5/5	Sep 2022	1,999	amazon.com
5.		Fujifilm X-T5	5/5	+ +	4.5/5	90/100	4.5/5	..	Nov 2022	1,699	amazon.com
6.		Fujifilm X-Pro3	4/5	+	4/5	85/100	4/5	..	Oct 2019	1,799	amazon.com
7.		Fujifilm X-T3	5/5	+ +	4.5/5	88/100	5/5	5/5	Sep 2018	1,499	ebay.com
8.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	1,899	ebay.com
9.		Fujifilm X-Pro2	..	+	..	83/100	4.5/5	4.5/5	Jan 2016	1,699	ebay.com
10.		Fujifilm X-T2	5/5	+ +	..	86/100	4.5/5	5/5	Jul 2016	1,599	ebay.com
11.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
12.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
13.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
14.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
15.		Sony A6600	4/5	+	4/5	83/100	4.5/5	4/5	Aug 2019	1,399	amazon.com
16.		Sony A77	5/5	91/100	..	81/100	..	5/5	Aug 2011	1,399	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.

Check X-T4 offers at
ebay.com
Check K-3 III price at
amazon.com

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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.

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