Pentax K-1 II Field Test Part III
Pentax K-1 II Field Test Part III
Pixel Shift Resolution can give photos a noticeable detail boost, even when used handheld!
By Mike Tomkins | Posted: 06/18/2019
As we work to tie off the final loose ends on our Pentax K-1 II review, I wanted to revisit the field tests for one more outing, this time taking a more in-depth look at the Pixel Shift Resolution functionality. If you're not already familiar with the feature, you may want to revisit our sub-frame Pentax K-3 II review briefly (and specifically, our article entitled Exploring the K-3 II's "Pixel Shift Resolution"), as this Pentax exclusive made its debut in that camera back in mid-2015.
A brief recap of Pixel Shift Resolution
But in a nutshell, the technique works by capturing four frames in the shortest time possible -- which varies depending upon whether an electronic or mechanical shutter is being used -- and microscopically adjusting the position of the image sensor between frames. In the process, the amount of light gathered is quadrupled, because instead of 2/3 of the incoming light being lost to a Bayer color filter array, every pixel location is now full-color sensitive, with data having been captured in red, green (twice) and blue.
Combined with an antialiasing filter-free design and a quality lens, this technique allows for extremely impressive per-pixel image quality and much better resistance to false color and color moire effects than a single shot. But there have until recently been some important gotchas due to the multi-shot nature of the technique. (And it still may not prove appropriate if there's a significant amount of motion.)
Moving subjects have to be accounted for and cannot have their resolution boosted, since their location varies between frames and so the precise readout of full-color info at each pixel can't take place. Camera motion is also a big issue for similar reasons, and again has to be taken into account by the technique. Flash exposure isn't possible, as the flash would have to be fired too rapidly for it to be used. And finally, until now an electronic shutter has had to be used, regardless of which type of Pixel Shift Resolution you're using.
The K-1 added support for subject motion, and now the K-1 II adds handheld capture
The K-1 II's predecessor, the Pentax K-1, largely resolved the issue with moving subjects by detecting and accounting for them, essentially automating a manual process I'd suggested in my K-3 II review. Moving subjects would be rendered using info only from one image frame captured during the Pixel Shift Resolution process, while static areas of the scene would receive the benefit of the other three frames.
And now, the followup K-1 II aims to resolve the issue of camera motion with the addition of a handheld variant of Pixel Shift Resolution, which also uses a mechanical rather than an electronic shutter which can, under some light sources, cause banding. In-camera, the new Pixel Shift Resolution variant doesn't have its own name per se, being indicated simply by the name Pixel Shift Resolution, and then an icon which it took me just a little while to figure out was intended to show a camera being held by its handgrip.
(I do think Ricoh needs to come up with a better way to indicate the function,but once you're familiar with what it is, it's easy enough to remember, I suppose. The existing tripod-based modes, incidentally, have icons that are similar, but with the in-hand camera replaced by the letters MC -- for motion correction -- either grayed out or not to indicate availability of the function.)
Time for a real-world Pixel Shift Resolution shootout
To see how its updated Pixel Shift Resolution function handles real-world shooting, I headed towards nearby downtown Knoxville, Tennessee, equipped with the camera itself, a reasonably sturdy tripod and a choice of three different lenses -- the HD PENTAX-D FA 15-30mm F2.8ED SDM WR, HD PENTAX-D FA 24-70mm F2.8ED SDM WR and HD PENTAX-D FA* 50mm F1.4 SDM AW. (Although as it happened, none of my shots with the latter made it into this article.
And before I go any further, I should note that all of the images in each group were captured with identical camera settings and autofocus distance, other than the fact that for the tripod-mounted shots I used a two-second self-timer, which I disabled for the handheld shots. I focused either automatically or manually for the first exposure in each series, then switched to manual focus for the rest of the shots in that series. For the handheld shot, I did my best to hold the camera in the same place that I'd had it for the tripod-mounted shots, being very careful not to touch the focus or zoom rings.
In all cases, the camera was set to MTF priority to yield the optimum lens aperture, and to ensure that shutter speeds wouldn't drop to low, the ISO sensitivity was also set to ramp up the ISO sensitivity faster than by default, to ensure shutter speeds would be sufficiently swift that blur from camera shake would be a non-issue, no matter the subject I was shooting. For the shots I selected in this field test, the automatically-selected sensitivity was ISO 200, and the shutter speed for the handheld shots ranged from 1/250th to 1/800th second. I also enabled raw+JPEG capture with a DNG file format, but otherwise left settings at their defaults.
Scene 1: Knoxville Arts District
The first group of shots I want to discuss in this article were also, as it happens, the first batch I took on this shoot. They weren't the first I captured in testing Pixel Shift Resolution, however. I'd already been out several times previously, gaining some early shots for my own information.
Much as I did then, on this final shoot I found that while handheld Pixel Shift Resolution shots could often better a standard, single exposure for detail, it wasn't always a given. Perhaps a quarter to a third of the time, I'd end up with a similarly-sharp result shooting handheld to that I'd previously captured in single-shot mode. (And just rarely, the single-shot exposure would actually seem a smidgen sharper, though never significantly so.)
For critical subjects -- and I'd imagine that's most of them, if you're taking the time to try and increase resolution in the first place -- it'd therefore probably be prudent to shoot both a standard and Pixel Shift Resolution version if you're planning on shooting handheld.
The shot (and crops) above are a nice example of this. Looking at the four crops above, it's pretty clear that there's little difference between the single-shot and handheld Pixel Shift Resolution shot in terms of detail-gathering performance. The fine details in the tripod-mounted Pixel Shift Resolution crops show noticeably more detail, although they do also show a little artifacting in the flags and the more subtle-moving signs, even in the motion-compensated crop.
From perusing the whole image, though, I think that if anything the handheld Pixel Shift Resolution image is just a smidgen less sharp than the single-shot capture here. Initially I thought the building at the top left of the image showed more detail in the Pixel Shift version, but I think that's just down to the front of the building being brighter in the single-shot capture due to the clouds passing overhead. (You can see a little of what I mean in the next group of crops.)
Here again, the tripod-mounted crops clearly show more detail than the single-shot or handheld ones. The handheld Pixel Shift Resolution crop does look sharper than the single-shot crop at first glance, but I think that's down to the more contrasty illumination of the building in the final shot. (You can see the clouds have moved significantly in the short time between exposures, as the window reflections have changed from white to blue.)
One place where the handheld Pixel Shift Resolution mode definitely bested the tripod-mounted modes was in its ability to handle moving subjects. I already mentioned the slight artifacting noticeable in the first set of crops, but it's much more so in the wind-blown trees and walking pedestrian here. And again, while the tripod-mounted shot with motion compensation enabled is a significant improvement over that in the uncompensated one, the handheld Pixel Shift Resolution shot is the only multi-shot capture not to show some artifacting in the moving subjects.
Scene 2: Old Knox County Courthouse and monuments
While my first set of shots above didn't show an image quality advantage for handheld Pixel Shift Resolution, more often than not the function came through for me as it did in the image and crops below.
Looking at the quartet of crops above, the handheld Pixel Shift Resolution crop definitely looks a bit sharper than the single-frame capture. (And this time, I don't think it's caused by the differences in light from both clouds and foliage casting shadows on the historic monuments outside of the old Knox County courthouse building.) But again, it's pretty clear that the tripod-mounted Pixel Shift Resolution shots are another step above in terms of detail.
Switching to a different monument that's not so greatly affected by shadows from the nearby trees, we again see a little bit crisper of a result in the handheld Pixel Shift Resolution image, and an even better result in the tripod-mounted ones.
And the same is also true of the crops above of text further down the same monument, even if there are some differences in the ambient light level. It's perhaps a subtle improvement for handheld Pixel Shift Resolution overall for this image, but a noticeable one nevertheless.
Scene 3: Regal Cinemas headquarters and One Riverwalk
For those of you who're not convinced yet, however, this third series should take you there. It's a pity that the subject itself is a bit bland, as it more-clearly showed what handheld Pixel Shift Resolution is capable of than any other in this series. Ah well, such is life.
Just a glance at the fine detail in the red and tan bricks on the front of Knoxville's new One Riverwalk apartment complex is enough to tell you that handheld Pixel Shift Resolution is working here. Sure, the tripod-mounted shots are even crisper, especially in the window blinds, but the difference between these and the handheld shot is less significant than that between the handheld and single-shot captures.
Also noticeable is that all three Pixel Shift Resolution crops show significantly less color moire in the window blinds, compared to the quite strong diagonal stripes of color across the blinds in the single-shot capture. Improved resistance to false color and moiré is one of the selling points for the earlier Pixel Shift Resolution modes. And while the handheld mode doesn't have the same alignment accuracy of the tripod-mounted version, it certainly seems to have helped out nevertheless.
One slightly curious thing, though, is that the tripod-mounted shots show a little bit of artifacting on and around the One Riverwalk sign, and in the front of the building around the windows. That's also true in the crops of Knoxville's famous JFG coffee sign below, and I can only hypothesize that perhaps with it being a rather breezy day, there was just sufficient vibration in my tripod to cause issues.
Be that as it may, though, the handheld Pixel Shift Resolution image had no such issues, and turned out the best result of the group overall. You can certainly see more fine detail in the light bulbs which illuminate the JFG sign at night, here.
Scene 4: Three Rivers Rambler at Volunteer Landing
Finally, I moved on to Knoxville's Volunteer Landing for one more set of exposures. And again, handheld Pixel Shift Resolution performed pretty well, yielding a slight but noticeable increase in detail while avoiding the artifacting of the tripod-mounted shots. And while the motion compensated crop again does much better than its uncompensated equivalent, it still misses some of the finer artifacting in the foliage.
That artifacting, incidentally, can show its head in unexpected places, too. When you look at trees swaying on a breezy day, it's pretty obvious that they're going to cause problems for a multi-shot capture technique like Pixel Shift Resolution. It's less immediately obvious that those same moving trees are going to cause issues in what at first glance would seem to be unrelated areas of the image, like the train above, though.
But look closely in the windows and the side of the train in the tripod-mounted crops above, and there's clearly just a little of the same artifacting going on here too. The reason: They're reflecting the trees, and when the trees sway, so to do their reflections, whether you as the photographer are conscious of that or not.
The same is also true of motion in shadows, as you can see in the final set of crops above. While the fence and lamp post are both crisper in the Pixel Shift Resolution images, there's significant artifacting in the uncompensated, tripod-mounted shot, and a little bit remains even in the motion compensated version. But once again, the handheld variant is unaffected.
Final thoughts on Pixel Shift Resolution and its handheld update
Going into this field test, I wanted to know how Ricoh's updated Pixel Shift Resolution mode would perform, and especially how usable its new handheld variant would be in real-world shooting. And now I'm done with my shooting and analysis, I have to say that the answer is "pretty well". It's not a magic bullet that will work all of the time, but in the right circumstances it is definitely capable of yielding a significantly sharper image on a per-pixel level than you can get from a single exposure. (And sometimes, it comes surprisingly close to matching even the invariably more precise tripod-mounted variants of Pixel Shift Resolution.)
And while it never quite equals the tripod-mounted Pixel Shift Resolution capabilities, the new handheld mode has proven to be far more resistant to issues with subject motion throughout my testing. Add in a greater resistance to false color and moiré and I think this is a mode that's definitely worth using if you're shooting relatively static subjects with lots of fine detail or repeating patterns. (Think both landscapes and cityscapes, in particular.)
I do recommend always shooting a backup single-shot exposure, but if you're, say, backpacking the Appalachian Trail and wanting to pack light, it's rather nice to be able to leave your tripod at home and still get really crisp results for just a little extra added effort. Kudos to Ricoh's engineers for figuring out how to bring to market a feature that, just a few short years ago, seemed unlikely to be possible any time soon!
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