PENTAX K-3 Mark III Camera Review

The PENTAX K-3 III isn't especially portable, but it isn't bad for a DSLR. It is heavy, though, since it uses a pentaprism for its viewfinder, which adds a bit of weight. If you'd prefer a more portable camera, consider a mirrorless alternative like the Olympus OM-D E-M1 Mark III.

The PENTAX K-3 Mark III feels very well-built. It has a sturdy magnesium alloy body with rubber-coated sides and thumb rest for better grip. The buttons and dials feel solid and offer good physical feedback. The inputs and outputs are covered by standard rubber flaps, while the battery compartment uses a secure locking hinged door.

The PENTAX K-3 Mark III uses the Pentax K-mount, which is compatible with K, KA, KAF, KAF2 (with power zoom), KAF3, or KAF4 lenses. The camera's weather-sealed and advertised to be dustproof as well as cold-resistant down to -10°C (14°F).

The camera has three command dials. By default in manual mode, the front dial near the shutter button controls shutter speed, the rear dial controls aperture, and the top dial (or 'E Dial') controls ISO. You can customize these and more (up to 10 buttons in total are customizable) to suit your preferences, and you can set different customizations for each shooting mode, which is great.

• PENTAX K3 Mark III camera body
• PENTAX DA 18-55mm f/3.5-5.6 AL WR lens
• Front and rear lens caps
• Lens hood
• Sensor cap
• Hot shoe cover
• Eye cup
• Viewfinder cover
• Shoulder strap
• D-LI90 battery
• AC adapter
• AC adapter plug
• USB-A to USB-C cable
• User manual

The PENTAX K-3 III feels incredibly comfortable to use. Its large handgrip fits the hand well, and it's suitable for all hand sizes to hold comfortably. The buttons and dials are well-spaced, making it easy to adjust settings with your eye to the viewfinder. It also has a top display, so you can quickly check settings and battery life at a glance.

The PENTAX K-3 Mark III uses a pentaprism in its viewfinder, which adds some weight to the camera but gives a clearer view through the viewfinder compared to a more inexpensive pentamirror mechanism. The eyecup around the viewfinder is very soft and comfortable.

The PENTAX K-3 III has a fixed screen, which is limiting for waist-level shooting or video work. The screen has a neat 'Night Vision' mode that decreases its luminosity and turns the display red for nighttime shooting.

The PENTAX K-3 III has a good menu system. While settings are all pretty clearly labeled, the submenus are very long and could be more clearly organized. Thankfully, there's a quick menu function to easily access more common settings and a smart function ('S.Fn' button) menu that can be customized to access up to five different settings. If you don't understand what a setting does, the camera has an info/guide function to explain.

The PENTAX K3 Mark III has a great battery life. Its 800-shot CIPA rating is better than most mirrorless models and is quite good for a DSLR, though it falls far short of some Nikon models like the Nikon D780. What that means is you're likely to get plenty out of this camera on a full charge, though that depends on how you use it.

It isn't quite as good for video, though it'll still last for about an hour and a half of continuous video recording. Just be aware that the battery can overheat when recording in 4k for longer periods.

The PENTAX K3 Mark III includes eight different shooting modes to give you more control over exposure parameters and 12 custom image modes to adapt to different scenes or desired effects. Each image mode is customizable, allowing you to manually adjust settings like hue, contrast, saturation, color temperature, and more to change up the look of JPEG files. Also, the electronic shutter function is only available after upgrading to firmware version 1.10.

The PENTAX K-3 III can shoot at a quick max burst rate of 11 fps, which is especially impressive relative to other DSLR cameras. It's more than fast enough for most shooting situations where you'd want to capture fast action like sports. That said, it has a very small photo buffer, even when shooting in JPEG, and on top of that, it takes a very long time for it to clear its buffer once full. That means even though you can shoot in quick bursts, you're going to quickly be interrupted, which isn't ideal when you're trying to capture fleeting moments.

The PENTAX K-3 Mark III has a decent autofocus system, although it's most effective when shooting through the viewfinder, which is what we used to achieve the results above. When shooting through the LCD monitor in Live View, the autofocus is very unreliable at tracking moving subjects. No surprise considering it uses a contrast-detection AF system here, unlike a DSLR like the Nikon D780, which implements faster phase-detection AF in Live View.

It does a decent job of tracking faces. It's a bit slow and can sometimes lose its target when the person is moving briskly towards the camera. Its general subject tracking does pretty well, though. All in all, it's an effective AF system that'll perform well for a variety of situations and subjects but doesn't quite compete with the leading AF systems found on the latest mirrorless cameras.

The PENTAX K-3 Mark III features in-body image stabilization, and it does a fantastic job of stabilizing the sensor, so you can get clear handheld shots at very slow shutter speeds. We used the Pentax HD-DA 16-50mm f/2.8ED PLM AW lens, which doesn't have optical stabilization, but you can expect similar performance even with a kit lens and possibly even better performance with an optically stabilized lens.

The PENTAX K-3 Mark III has excellent dynamic range. It's right up there as far as APS-C cameras go and even surpasses a lot of older full-frame DSLRs. All in all, it can capture a wide range of highlight and shadow detail in high-contrast scenes. It also has really good exposure latitude, so you can make pretty significant exposure adjustments to your photos without introducing a whole lot of noise.

The PENTAX K-3 III takes very detailed photos. It does a good job of resolving fine detail, though this is mostly apparent when pixel-peeping.

Noise handling is excellent when shooting in JPEG. The camera processes photos well at high ISOs, so noise is barely visible, though of course in dim lighting conditions, it's harder to avoid introducing noise, and photos become unusable at the extreme end of the camera's ISO settings. That's especially the case at the camera's max ISO of 1,600,000, as you can see here. That said, there are very few, if any, real-world scenarios in which you'd use ISO 1,600,000, which is more of a marketing gimmick, so it's not an issue.

The PENTAX K3 III can shoot in either DNG or PEF, which is Pentax's proprietary RAW format. The above results are what we measured using PEF. Below you can see the results using DNG and see the graph here.

• RAW SNR 18% At ISO 100: 41.11 dB
• RAW SNR 18% At ISO 200: 40.01 dB
• RAW SNR 18% At ISO 400: 39.11 dB
• RAW SNR 18% At ISO 800: 37.75 dB
• RAW SNR 18% At ISO 1600: 35.62 dB
• RAW SNR 18% At ISO 3200: 33.06 dB
• RAW SNR 18% At ISO 6400: 30.59 dB
• RAW SNR 18% At ISO 12800: 27.65 dB
• RAW SNR 18% At ISO 25600: 24.89 dB
• RAW SNR 18% At ISO 51200: 22.61 dB

The differences are marginal, so you can just use whichever format you prefer.

The camera has fantastic RAW noise handling, far better than most APS-C cameras we've tested. With shorter exposure times at high ISOs, noise is more visible, but RAW files are still relatively clean.

The PENTAX K-3 can only record 4k video with an additional 1.33x crop. It can't record 4k / 60 fps like the latest video-centric cameras can, but it records at up to 30 fps, which is great for standard and more cinematic video work. You just can't get smooth action footage or create slow-motion 4k video with these frame rates.

Internal recording isn't great in 4k, but that's not unusual, considering this camera's mainly aimed at photographers. It's capped to a seven-and-a-half-minute recording time, which doesn't give you a lot of time to record. Bit rates are also small, and it can only capture 8-bit 4:2:0 video internally, so it isn't capturing a great amount of information, resulting in lower overall video quality.

The PENTAX K-3 Mark III has a poor autofocus system when shooting 4k video. It's slow and unreliable, even when using a high-end lens like the DA 16-50mm f/2.8, which uses a PLM motor for autofocusing. While the motor is quiet, which is good for video work, it's still very slow to focus. The camera has face detection and does a good job of recognizing human subjects in the frame, but ultimately, it struggles to keep up with moving subjects.

Video quality is okay in 4k. It looks reasonably sharp and detailed, but because the camera can only record cropped 4k, it's using a smaller portion of the sensor, resulting in slightly worse quality than you might expect for 4k. In low light, video looks quite noisy and grainy, and the camera has trouble bringing out detail in the shadows.

The rolling shutter is passable. There's some noticeable skewing when panning the camera, but it isn't terrible and won't be too noticeable with slower camera movements.

In 1080p, the camera can record at up to 60 fps, which is great if you want to incorporate some light slow-motion footage into your videos or simply record smooth action video.

You can record a lot longer in 1080p than in 4k, though at 25 minutes, it falls a little bit short of the typical half-hour mark we see on most cameras. Bit rates are decent and about on par with other APS-C DSLRs, but in the age of mirrorless cameras with advanced video capability, it's a little underwhelming, though this camera is aimed mostly at photographers, so it isn't unexpected.

The autofocus doesn't perform very well in 1080p, either. It's especially bad at tracking faces. It frequently misses or loses its target, even if they're moving at a moderate pace. The general subject tracking is passable. It eventually finds its target, but it's still slow, having to play catch-up with moving subjects.

1080p video quality is mediocre. Videos look soft and lack detail, even when the scene is in focus. It doesn't fare any better in low light, where noise is highly visible, and shadow detail gets lost.

Thankfully, rolling shutter effect is better in 1080p. It's still present when the camera is moving very quickly, but you're much less likely to have distracting skewing or distortion in Full HD than you are in 4k.

The PENTAX K3 III has two SD card slots, though only one is rated for faster UHS-II cards. It's still a welcome addition, and given the camera's limited buffer, the advantage of a UHS-II card is marginal. There are three different storage settings when two SD cards are inserted, including sequential, which switches to the backup after the card in Slot 1 is full, duplicate, which uses the second card as a running backup, or an option to store RAW and JPEG photos separately on each card.

The PENTAX comes equipped with plenty of inputs and outputs. It even has a cable release port, which is handy for long-exposure shots. It also has both a microphone and a headphone jack, as well as Micro HDMI and USB-C ports. All the ports are securely covered thanks to the camera's all-weather design.