Pentax K-3 Mark III Review

For longtime Pentax owners, the K-3 Mark III ($1,999.95, body only) is a hotly anticipated camera. Its development was documented in an ongoing marketing campaign, and after some delays it’s finally shipping. There are reasons for system owners to get excited for the first update to the K-3 in half a decade, including a new autofocus engine, an improved video toolkit, and the rugged, all-weather build brand loyalists expect. In spite of these advances, the K-3 III doesn’t match competitors in features, performance, or pricing. Dedicated Pentax users and SLR stalwarts should take a look, but photographers shopping for an APS-C system camera will be much better served by the Fujifilm X-T4.

A Reimagined K-3

The K-3 II didn’t do much to move the needle in terms of design. A few updates aside, It was the same body as its predecessor, not surprising as its release came just a couple of years after the first K-3.

(Photo: Jim Fisher)

Engineers at Ricoh (the parent company behind the Pentax brand) have had more time to develop the K-3 III. The series was put on ice for a few years, with the KP serving as the interim flagship. Its slimmed-down design, meant to compete with mirrorless systems, didn’t quite work. The KP was neither fish nor fowl and suffered from it.

The K-3 III focuses on the fundamentals. Its body is sized and shaped like other cameras, with an ample handgrip for better balance when pairing with the telephoto lenses used for sports, action, and wildlife disciplines. It feels much more like the K-3 (and earlier K-5 series) in the hand, with some serious refinements to improve ergonomics.

(Photo: Jim Fisher)

It’s an APS-C sensor camera, not a full-frame like the Pentax K-1 Mark II. The K-3 III is a little smaller all around, coming in at 4.1 by 5.3 by 2.9 inches (HWD) and 1.8 pounds without a lens attached. You can still use it with full-frame lenses; one of the strengths of the Pentax system is compatibility with autofocus lenses dating from the 1980s and manual focus optics from the ’70s.

HD D FA 150-450mm F4.5-5.6 ED DC AW, 250mm, f/8, 1/1,000-second, ISO 800 (Photo: Jim Fisher)

The body is magnesium, finished in your choice of black or silver. It includes internal seals to protect it from dust and splashes. When paired with a WR or AW series lens, you can use the kit in inclement weather. Not every current-generation Pentax lens is protected, but many are, including low-cost options like the $450 HD DA 55-300mm F4.5-6.3 ED PLM WR RE.

Familiar Controls, With Enhancements

The K-3 III will feel instantly familiar to K-3 veterans. The contours of the grip follow the same lines, and while there have been a few tweaks to the controls, it won’t take too long to adjust.

(Photo: Jim Fisher)

The basics—the front and rear control dials, shutter control, and rear AF button—are all in the same places. They’re joined by a pair of new top plate dials. One switches between viewfinder, live view photography, and video modes—it’s a bit out of the way, at the front, flanked by the viewfinder prism.

The second dial is a flexible control. It can perform a number of different functions, swapped and configured using the S.Fn button. I found it especially useful to swap between focus modes on the fly. It makes it easier to get the most out of the upgraded autofocus system.

(Photo: Jim Fisher)

The big change on the rear is an eight-way controller, basically a small joystick for direct control of the autofocus area. It’s next to the Green button, one that’s unique to Pentax. It does a few different things, ranging from shifting to automatic exposure when working in manual modes to toggling automatic ISO control.

Display and Viewfinder

The rear display is a fixed, 3.2-inch LCD with touch support. It’s bright and sharp (1.62 million dots), so you can use it to set focus manually with reliability. I do wish it had some tilt—it’s a lot easier to frame shots from low angles if you can look down on a viewscreen from above, after all. It’s a common feature in mirrorless and not unheard of in competing SLRs—both the Nikon D500 and Canon EOS 90D include articulating screens.

(Photo: Jim Fisher)

The optical viewfinder is a treat. It offers a high magnification, in line with full-frame SLRs (0.7x), and just a little bit smaller than similarly specced EVF models like the Fujifilm X-T4 (0.75x). It has a slight matte finish, a boon for manual focus.

You can set different overlay information to your liking. I enabled the viewfinder framing grid, and it always shows the outline that defines the area of the frame covered by the autofocus system, along with the set focus point or points.

HD DA 40mm F2.8 Limited, f/2.8, 1/800-second, ISO 200 (Photo: Jim Fisher)

The black boxes that represent focus points are easy enough to see when working outdoors under the sun, but are a little harder to see when working indoors or in dim light. The points are lit—they flash red when moved or when focus is acquired—but it’s a little too brief. It’s a typical experience for an SLR, and one that shows a problem that mirrorless cameras have solved—with an EVF you’ll always see your focus point clearly, even in dim light.

Power and Connectivity

The K-3 III uses the same D-L190 rechargeable battery that’s powered Pentax cameras dating back to the K-7. It offers some consistency for photographers who’ve been in the system for a long time. SLRs don’t use as much power as mirrorless cameras, netting an estimated 800 shots per charge.

(Photo: Jim Fisher)

You’ll get a lot more if you take advantage of burst capture, and fewer if you spend more time using live view, Wi-Fi, or recording video. Any way you slice it, the K-3 III can be an all-day camera with a fully topped-off battery, and if you’ve been shooting Pentax for years, you’re sure to have a few spares around to carry if you do run out of juice.

On-the-go charging is an option, too. The battery charges in-body via USB-C, so it’s easy enough to top off with a power bank or your laptop or iPad adapter when traveling. You don’t get an external charger for the battery in the box, though. Pentax is expecting K-3 III buyers to already have one, or to rely on charging in-body. If you prefer an external charger, Wasabi sells one for $25, or you can budget $50 for the official K-BC90 from Pentax.

Ricoh Image Sync app

Wireless image transfer to a smartphone or tablet is supported, too. The K-3 III works with the Ricoh Image Sync app, a free download for Android and iOS devices. I tried the iOS version on an iPhone 8 Plus and was happy to see that the app has been revamped since we last looked at it.

The connection process is a little clumsy. The K-3 III supports Bluetooth, a feature that typically eases setup. I ran into some hiccups, though. The app asked me to enter the camera’s identifying information a couple of times, but didn’t seem to connect.

HD D FA 150-450mm F4.5-5.6 ED DC AW, 450mm, f/8, 1/125-second, ISO 100 (Photo: Jim Fisher)

I ended up having to enter the K-3’s Wi-Fi password into the iOS settings panel manually, something that other Wi-Fi apps have sidestepped for years. It’s a manual step that you’ll need to take every time you connect the camera to your phone.

Once that was done, I was able to browse through images on the memory card and control the K-3 III with my iPhone. Image transfers are speedy, and you have the option of offloading 4K video and Raw DNG images if you want to edit on your smart device. It works quite well and the interface is clean and clear, in contrast with the buggy, confusing interface that plagued previous iterations of Image Sync.

(Photo: Jim Fisher)

In addition to USB-C, the K-3 III includes micro HDMI, headphone, and microphone connections on its left side panel. A PC Sync port is there for sync, and there’s a hot shoe if you prefer to use a wireless TTL transmitter or simply want to attach an external flash. Like the K-3 II, the Mark III omits an in-body flash.

Media is saved to SDXC cards. The K-3 III has two slots, but only Slot 1 supports speedy UHS-II cards. You’ll want to use the fastest cards you can get, especially if you take advantage of burst capture. The buffer is only good for about 25 Raw or 35 JPGs, and if you fill it up you’ll have to wait between 15 and 20 seconds to commit all photos to memory. When using the UHS-I slot you’ll get a similar amount of shots, but you’ll wait a few seconds longer for the buffer to clear. I tested the camera with Sony Tough cards rated for 299MBps write speeds.

All New Autofocus System

The K-3 III swaps out the aging 27-point autofocus system for a new version of the SAFOX engine. It includes 101 selectable focus points, spread out across a wider area of the frame. The camera focuses quickly, with confidence, though not with perfect accuracy. It’s able to capture images at up to 10fps, with focus and exposure for every shot. It’s the best autofocus you’ll get out of a Pentax camera, and while not the equal of the Nikon D500, it’s not too far behind.

Pentax K-3 III Autofocus Spread

It also adds some features that you don’t get with other SLRs, including support for eye detection in the viewfinder. It’s effective for portrait work, especially for headshots and head-and-shoulder shots, but not nearly as good as Canon, Fujifilm, or Sony mirrorless cameras—they’re able to detect eyes and faces that aren’t as prominent in the frame.

When paired with a quality lens, the K-3 III offers focus that’s not just quick, but accurate, and good enough to track action. With the HD 150-450mm, a big full-frame zoom with a DC focus motor, I was able to snap shots of birds in flight with a lot more shots in focus than out.

DA* 300mm F4 ED [IF] SDM + 1.4x TC, f/5.6, 420mm, 1/500-second, ISO 8000 (Photo: Jim Fisher)

Results weren’t as good with the DA* 300mm F4, a premium made-for-APS prime. Its SDM motor struggled to find proper focus. I ended up with as many misfocused shots as clear ones. You may also use screw-drive lenses. The compact primes in the HD Limited family are driven this way. In practice you’ll notice some extra noise, especially if the lens has to hunt to find focus.

If you’re buying new lenses for the camera today, you’ll be limited to Pentax autofocus optics. The move to mirrorless is only part of the story. Sigma and Tamron dropped support for K-mount prior to their final generation of superb SLR lenses. Most of Sigma’s Art and Sports lenses and Tamron’s SP series never made it to Pentax.

Stabilized Imaging

The K-3 III puts its 25.7MP BSI CMOS sensor onto a 5-axis image stabilization system. The stabilization system is effective, good enough for handheld exposures at half-second shutter speeds in practice.

HD D FA 150-450mm F4.5-5.6 ED DC AW, 450mm, f/8, 1/1,000-second, ISO 640 (Photo: Jim Fisher)

It works quite well with wide and standard lenses. The experience suffers with telephotos, though. The viewfinder is shaky when working handheld—remember Pentax lenses don’t have their own optical stabilization. The IBIS system still removes blur from handheld photos, but you’ll see every shake and shudder in the viewfinder.

It’s an area where Canon and Nikon SLRs have a leg up. They don’t include IBIS, so you need to buy stabilized lenses, but all quality telephotos for those systems have OIS. Mirrorless cameras take it a step further with hybrid systems that benefit from both lens and body stabilization, and always show a steady view in an EVF.

HD DA 40mm F2.8 Limited, f/4, 1/500-second, ISO 1600 (Photo: Jim Fisher)

The sensor supports a wide ISO range, starting down at 100 and ranging to an extreme ISO 16000000 sensitivity. Claiming you can set the ISO in the millions is fine marketing fodder, but not that practical for photography. There’s enough noise to introduce a magenta color shift starting at ISO 204800, and while you can still make out shapes in photos, noise kills all detail.

The output at ISO 51200 and 102400 is impressive, especially when you remember this is an APS-C, not a full-frame, camera. Very fine detail isn’t captured—the noise pattern is big and rough enough to wipe it away—but colors shine through. There’s a good deal noise at ISO 12800 and 25600, but images made at lower sensitivities are clean and clear.

DA* 300mm F4 ED [IF] SDM + 1.4x TC, f/8, 1/400-second, ISO 2000 (Photo: Jim Fisher)

You can fine-tune the camera’s noise reduction engine to taste. If you prefer less noise you can ramp it up, or you can dial it back if you don’t mind a grainy image. The camera goes as far as to allow you to set a custom level for each ISO. For Raw capture it’s up to your processor—I evaluated our test images using Adobe Lightroom Classic.

See How We Test Cameras

Raw imaging isn’t just about taking control of noise reduction. The K-3 III’s files offer plenty of flexibility to adjust exposure and color. Its files capture scenes with dramatic lighting easily, retaining detail in highlights and shadows.

DA* 300mm F4 ED [IF] SDM, f/5, 1/500-second, ISO 400 (Photo: Jim Fisher)

The stabilized sensor opens up a few advanced operating modes. It can move slightly during exposure, simulating a low-pass filter to eliminate false color moiré from certain scenes. There’s also a multi-shot mode for improved color sampling, beneficial for landscape and macro work.

The K-3 III still supports Astrotracer, the star tracking function introduced in the K-3 II. It moves the sensor to compensate for the earth’s rotation, netting longer night sky shots with pinpoint stars. Astro specialists who want to continue to use the feature will need to add the Pentax O-GPS ($199.95).

4K Video

The camera records at 1080p quality using its full sensor width at 24, 30, or 60fps. It works at 4K as well, at either 24 or 30fps. All of the color profiles available for stills are there for video, too. You can go for the default look (Bright) or switch to Vivid, Neutral, or Black-and-White profiles. There are some creative options, too—Bleach Bypass, Reversal Film, and Cross Processing—and a Flat profile for videographers who want to adjust color in post.

Aside from a heavy crop, the 4K footage looks good, with some caveats. It shows strong detail, and when it’s locked down on a tripod, the video is stable. The readout speed limits handheld work, and when coupled with IBIS it nets footage with an ugly jello effect. It’s a better video camera at 1080p—there are fewer pixels, but it sidesteps motion artifacts and uses the full sensor width for better wide-angle coverage.

Autofocus is very basic in video—you can drive it manually at any time, but there’s no full-time continuous focus available. Other cameras, including the Fujifilm X-T4, Nikon Z 6, and Sony a7C, are better all around for moving pictures—they offer superior autofocus, uncropped 4K, and a wide range of picture profiles and flat looks. They’re also all mirrorless EVF cameras. It’s not a coincidence. Mirrorless bodies are better suited for hybrid stills-video workflows than SLRs, generally speaking.

It’s Finally Here

In Pentax circles, the K-3 III is a hotly anticipated release. It’s the first update to the enthusiast-oriented K-3 series in years, and offers some real reasons for photographers clinging to a K-3 or K-3 II to upgrade. And there are plenty of reasons to make room in your budget for the Mark III, including an autofocus system that competes with Canon and Nikon SLRs, an updated image sensor for better photos, and compatibility with lenses going back nearly 50 years.

HD D FA 150-450mm F4.5-5.6 ED DC AW, 450mm, f/8, 1/1,000-second, ISO 800 (Photo: Jim Fisher)

The autofocus engine is especially appealing for Pentaxians photographing moving subjects. The K-3 III is more confident with birds in flight and similarly challenging scenes, and it spreads the focus points across a wider area of the frame than the K-3 II and KP. It’s still not quite the equal of the Nikon D500, or any enthusiast-oriented mirrorless camera. But compared with earlier efforts from Pentax, the autofocus system is almost revolutionary.

For system owners—folks with too many DA series lenses and accessories to consider moving on—the K-3 Mark III is worth its salt. The camera comes with premium pricing—it’s an APS-C camera that costs more than some with full-frame sensors. It’s built to high standards, and a relatively small market share means that using a Pentax camera today costs more than systems with larger user bases.

It makes the K-3 Mark III a natural upgrade for photographers already working with Pentax cameras and lenses. For everyone else, it’s a hard sell. You can get more camera for less money with other systems.

The Fujifilm X-T4 is our favorite APS-C model and, in many ways, a spiritual successor to landmark Pentax models like the K10D, K-5, and K-3. The X-T4’s ergonomics are sublime, it’s built for all-weather use, and is backed by a line of quality, compact primes—the same reasons folks bought Pentax SLRs ten or fifteen years ago. The X-T4’s EVF may take some getting used if you’ve only used SLRs, but the benefits are worth an adjustment period.

(Photo: Jim Fisher)

If you can’t handle an EVF, the K-3 Mark III isn’t the only SLR out there. If you don’t already own Pentax lenses, the Canon EOS 90D is a stronger buy, especially if you care about video. It has a wider selection of recent autofocus lenses, a flip-out LCD, and speedy 4K video focus. It’s not built as well, though. If you’re after a pro-grade body, the Nikon D500 is still the best APS SLR you can get, but has been hard to find at retail in recent months. Like most of the industry, Nikon has devoted its resources to its mirrorless system.

Thanks to Lensrentals for providing equipment to support this review.