Pentax K-5 IIs Brief Review
by Mike Tomkins
Preview posted 09/10/2012
Review posted 06/04/2013
With the K-5 IIs, Pentax is borrowing a page from Nikon's playbook. Launched alongside its Pentax K-5 II digital SLR, the extremely closely-related K-5 IIs variant removes the optical low-pass filter, allowing slightly sharper images at the risk of increased moiré patterns, false colors, and other aliasing artifacts.
Like Nikon, Pentax is charging around a 10% premium for the K-5 IIs, with list pricing currently set at around US$1,100, approximately US$100 below its launch price. Unlike its rival, though, Pentax is apparently looking for broader distribution for the new camera, with availability since October 2012, both online and at retail in many brick-and-mortar stores that also carry the K-5 II.
So--how does the K-5 IIs achieve higher resolution than its sibling? Like almost all Bayer-filtered cameras, the design of the standard Pentax K-5 II places an optical low-pass filter (OLPF) just above the image sensor. This filter is designed to blur incoming light just slightly, so as to prevent aliasing patterns -- moiré and 'jaggies' -- from appearing in images. Unfortunately, this filter also blurs out some subtle image detail, reducing per-pixel sharpness.
By removing the filter, you get that sharpness back--but you also have to deal with the image defects the filter was designed to hide. In some types of photography they're not too much of an issue, or you can work to reduce their impact. In the studio you can adjust your subject to minimize moiré in fabrics and hair, for example. In nature, the fine repeating patterns that cause moiré to rear its head aren't so common. (Although they do certainly appear: think hair, fur, feathers, patterns in coloring of flowers, insects, and so on.) Should some defects get past you in shooting, some work in the digital darkroom can minimize its impact, as well. Hence landscape and studio photographers, among others, may be willing to trade off the risk of moiré and jaggies to achieve the maximum possible detail.
The Pentax K-5 IIs is designed with those photographers in mind. For others, while the thought of greater per-pixel sharpness may appeal, the slight benefit in that area is likely not worth the downside of having to work around the moiré issues. That will doubtless limit the Pentax K-5 IIs' sales, but it's still great that companies like Pentax and Nikon now recognize -- and cater to -- the needs of niche markets like these. And if you're not ready for the hassle of an OLPF-free camera, then you've still got the K-5 II to consider!
In all respects bar the OLPF, the specialist Pentax K-5 IIs is identical to its mainstream sibling -- all bar the price, anyway. And for that reason, we're not going to look at most of its feature-set in this review: if you're interested in the K-5 IIs, get a basic grounding with our Pentax K-5 II review first, and then come back here for the final verdict on image quality.
If you've already read our K-5 II review, and you understand fully what you're getting into when you ditch the OLPF, then read on and find out if it's a worthwhile tradeoff!
Pentax K-5 IIs Shooter's Report
by Mike Tomkins
When I flew to my one-time home in Hong Kong earlier this year for a much-needed vacation, I had the option of taking either the Pentax K-5 II or K-5 IIs with me. I did briefly entertain the thought of taking both, but concerns about the added bulk of two DSLR bodies put paid to that idea -- my wife and I had a four-year old to entertain on an extremely long trip, and our bags were already groaning at the seams with suitable distractions, plus all of our electronic gear. (Putting all of that in an easily-opened case in the hold simply wasn't an option.)
Decisions, decisions. I hemmed and hawed for a while -- deep down I'm the kind of person who finds the extra sharpness of an OLPF-free camera attractive -- but in the end my rational side won, and the K-5 II took the trip, while the IIs sat on the shelf back home. Since my return, I've shot both cameras extensively, though, and as you'd expect I noticed absolutely no difference between the two in terms of handling and shooting in the field.
So why did I take the K-5 II on my trip, rather than the K-5 IIs? Well, from the get-go Imaging Resource has had concerns about the potential for aliasing and moiré issues with OLPF-free cameras in general, and those were borne out in our review of the Nikon D800E late last year. I was expecting the same with the Pentax K-5 IIs, and while as it happens I didn't hit anything nearly so severe as we saw with the Nikon, that's likely down to dumb luck in my not hitting a subject of the right spatial frequency. This being a personal trip, and one I can't often make at that, I simply didn't want the hassle of fixing moiré in even a small portion of the hundreds of images I expected to shoot. (As it turned out, I shot almost 1,100 images in the course of the twelve-day trip.)
For the most part, the difference in sharpness between the K-5 II and the low-pass-filter-free K-5 IIs is pretty subtle, but occasionally a subject just feels more life-like viewed at 1:1 resolution in images from the K-5 IIs. This image is a nice example: I don't think my K-5 would've held onto some of the finer details in this weathered bicycle sculpture -- although a touch of unsharp mask would've probably brought the two cameras closer to parity.
Knowledge is power. If you're considering the K-5 IIs, you need to be aware of that possibility yourself, and to make your buying decision appropriately. Moiré is going to be more of an issue with some subjects than others -- specifically, those with repeating patterns can be problematic. That's especially true of a lot of man-made objects -- think things like brick walls, fencing, fabrics, and more. It's also true in the natural world, though. Hair, fur, feathers, and the fine patterns you often see on bugs and flowers are particularly likely to cause issues. Depending on the subject, you may be able to fix the problems with cloning or other techniques, but do you really want to take on that hassle?
A real-world comparison. With all of that said, once I was back home in Knoxville I went out shooting with the K-5 IIs. I didn't want my concerns to bias the results in either direction, so I didn't actively seek out subjects likely to cause aliasing, and nor did I try to avoid problematic subjects -- I just shot as I would with any other camera.
In my own photos, the issues weren't anywhere near as frequent as I'd worried, but they did crop up now and then -- and as I've said, it's likely I simply didn't happen on quite the right subject for a more prominent issue. Window blinds, vent / drain gratings, and power cables were the most common culprits for me. I've included a couple of examples highlighting the moiré / false color below, and in the comparison crops. (See the air conditioner grille in the second shot with the 40mm prime lens.)
Test conditions. The comparisons, by the way, pit the Pentax K-5 IIs directly against both the K-5 and K-5 II. Note that all of these were shot moments apart with the exact same lens (that is, not the same model, but the same individual copy -- I switched it back and forth between cameras). All were shot with the camera mounted on my sturdiest tripod to try and retain the same framing. I used two lenses for the shots: both my smc PENTAX-DA 21mm F3.2 AL Limited and smc PENTAX-DA 40mm F2.8 Limited primes.
Unfortunately I only had one tripod mount compatible with the particular tripod I'd chosen, and in switching it back and forth between bodies, couldn't quite match the alignment perfectly on the three bodies. Hence, the framing isn't 100% identical, but it's pretty close. All three cameras were set in live view mode, allowed to focus automatically on the same high-contrast point in the scene, and then switched to manual mode to lock focus across a bracketed series of three exposures.
The base exposure was set by letting the first camera shot (the K-5 IIs) determine the exposure in program mode at my chosen sensitivity. I then switched all three cameras to Manual exposure, selected the same shutter speed, aperture, and ISO sensitivity, and shot each in sequence -- first the K-5 IIs, then my K-5, then the K-5 II. (I'd meant to shoot my K-5 last, but transposed the order in the first set of shots, so stuck with it for the remainder to avoid confusion.)
All settings for each camera were at the default with the sole exception of file type (Raw+JPEG), drive mode (three-shot bracketed with self-timer, +/-0.7EV steps), and clock (which I plain forgot to check - d'oh!) I did also confirm that the default setup was identical for the trio. In other words, this test was as close as I could manage out in the real world to obtaining identical images from all three cameras. Oh, and one last note: What I'm showing here are 100% crops from the same area of each image. If you click on the crop, you'll be taken to the original image, available in both JPEG and raw formats, so you can make your own comparisons, and draw your own conclusions.
And now, without any further ado, to the comparisons:
|Pentax K-5||Pentax K-5 IIs||Pentax K-5 II|
|smc Pentax-DA 21mm F3.2 AL Limited|
|smc Pentax-DA 40mm F2.8 Limited|
Still Life studio shots compared to Pentax K-5 II
Below are crops comparing the Pentax K-5 II and Pentax K-5 IIs.
NOTE: These images are best quality JPEGs straight out of the camera, at default settings including noise reduction. Both cameras were shot with the same, very sharp reference lens (Sigma 70mm f/2.8 EX DG Macro), one of the sharpest lenses we've ever tested.
Pentax K-5 II versus Pentax K-5 IIs at ISO 100
Pentax K-5 II versus Pentax K-5 IIs at ISO 1,600
|High Contrast Detail|
Pentax K-5 II at ISO 100
Pentax K-5 IIs at ISO 100
|Pentax K-5 II at ISO 1,600||Pentax K-5 IIs at ISO 1,600|
Resolution Chart Comparisons
|In-camera JPEG (ISO 100)|
Pentax K-5 II
Pentax K-5 IIs
Pentax K-5 II
Pentax K-5 IIs
|RAW (ISO 100)|
Pentax K-5 II
Pentax K-5 IIs
Pentax K-5 II
Pentax K-5 IIs
Pentax K-5 IIs Print Quality
Excellent print quality up to 24 x 36 inches at ISO 80/100/200; ISO 1600 capable of a good 11 x 14 inch print; ISO 12,800 still able to deliver a good 4 x 6. (Note: the K-5 IIs creates noticeable oversaturation in some colors of our test images.)
ISO 400 prints lose only a minor amount of detail in a few areas like the mosaic tiles, but are quite sharp at 20 x 30 inches.
ISO 800 images were oh-so-close at 20 x 30, but show marginal loss in contrast in our difficult target red leaf swatch and some apparent noise in the shadowy areas of our target. To be safe we'll call 16 x 20 good at this ISO, just as we did with the K-5 II.
ISO 1,600 prints at 11 x 14 lose all contrast detail in our target red swatch, but are otherwise quite good.
ISO 3,200 makes a nice 8 x 10 inch print, again losing all detail in our red swatch but good in all other areas.
ISO 6,400 prints a nice 5 x 7, with only minor grain in the shadows.
ISO 12,800 prints a nice 4 x 6, which still is a good size for this ISO.
ISO 25,600/51,200 prints are not usable at any size and are best avoided.
The Pentax K5-IIs with its APS-C 16.3mp sensor and lack of an optical low-pass filter yields a nice range of printed images across most of the ISO spectrum, producing comparable print sizes to most of its competitors in this sensor size and price range and yielding slightly sharper images overall than its sibling the K-5 II with its low-pass filter. Note however that at all sizes and ISO ranges our target magenta fabric swatch has a noticeable boost in saturation, and is tinted slightly more towards purple than the actual swatch color.
Testing hundreds of digital cameras, we've found that you can only tell just so much about a camera's image quality by viewing its images on-screen. Ultimately, there's no substitute for printing a lot of images and examining them closely. For this reason, we now routinely print sample images from the cameras we test on our Canon Pro9000 Mark II studio printer, and on the Pixma MP610 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)
In the Box
- Pentax K-5 IIs digital camera
- Lithium-ion rechargeable battery pack D-LI90
- Battery charger kit K-BC90
- Body cap
- Eyecup FR
- Finder cap for ME
- PC socket cap
- Hotshoe cover FK
- Focusing screen MF-60 Frame Matte (aka Natural-Bright-Matte III)
- USB data cable I-USB7
- Audio/video cable I-AVC7
- Shoulder strap O-ST132
- Software CD-ROM S-SW132
- One-year limited warranty
- Protective case
- Extra battery pack for extended outings
- Large capacity, high-speed SDHC/SDXC memory card. 8-16GB or larger makes sense if you plan on shooting lots of HD video. Look for a speed grade of at least Class 6 for video capture.
- High-quality lenses (especially primes) to take advantage of the OLPF-free design
- External flash
- Additional focusing screens
Pentax K-5 IIs Conclusion
For years now, we've heard readers asking the camera manufacturers to offer a camera without an optical low-pass filter in the quest for the maximum possible resolution. Some have seen OLPF-free digicams as something of a holy grail, but the truth of the matter is that removing the low-pass filter is not a magic bullet -- the improvement in per-pixel sharpness is real -- if your lens resolves sufficient detail, anyway -- but so too is the occurrence of moiré and other untoward artifacts of a camera's Bayer filter array.
With the Pentax K-5 IIs, moiré problems may not have struck for me quite as often as I had been worried that they might, but at the same time, the difference in sharpness was also rather more slight than I was expecting. Yes, when viewed at 1:1 the K-5 IIs clearly has an advantage over the K-5 II in per-pixel sharpness, but it's not a difference you're going to notice unless you're looking at your images very closely. Even then, a touch of unsharp masking on both images will often leave the K-5 II's result near-indistinguishable from that shot with the K-5 IIs.
For some purposes, that little extra sharpness might be worthwhile, but for my money it's simply not worth the risk of a hard-to-remove artifact in a once-in-a-lifetime shot. The slight reduction in sharpness is one I'm willing to make, for the peace of mind it brings.
If you know your subjects won't be prone to moiré, you have the ability to control the situation to avoid it, the patience to repair it when it does show up, or you have an absolute need for a camera without an antialiasing filter*, then the Pentax K-5 IIs should prove very interesting.
Putting our concerns aside for a moment, though, we're glad to see Pentax provide you with that option. The overwhelming majority of photographers would be best advised to stay with the standard Pentax K-5 II instead of its more specialized sibling, however. We'd recommend you read our Pentax K-5 II review to find out if that would be the better camera for you.
(*We should note that, perhaps, that we don't know for sure if the filter has been removed, or if its effect has simply been canceled out. We do know that rival Nikon uses the cancellation approach.)
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