Let’s get one thing straight, with 4K
clarity: The UHD50, one of Optoma’s
latest range of 4K-capable projectors,
isn’t a native UHD model. It’s a 4K pixel
shifter. That means it uses a 1080p DLP
chip, and “shifts” the image at high speed
to create a full UHD pixel grid.
But there’s pixel shifting, then there’s
pixel shifting. Optoma claims its take
on it is superior. Or rather, it’s the pixel-
shifting tech from Texas Instruments,
known as XPR, that’s superior to its main
competitor, that of LCD projectors.
The idea is fairly straightforward to
grasp: Project an image, then shift it
slightly, and project it again with updated
pixel data, but do it so fast the human eye
perceives the result as a single, unified
image. In really simple terms, you can
think of LCD pixel-shift projectors as
bumping the image once diagonally.
Pixel-shifting 4K LCD projectors thus
offer double the truly addressable pixels
of a 1080p model. Of course, full 4K is four
times the pixels of 1080p, so you’re only
getting half the detail. With TI’s XPR pixel
shifting, the 1080p image is moved right,
then down, then left, delivering fully
four times the pixels of 1080p. This all
happens fast enough to be imperceptible.
In practice, the projector runs at 240Hz,
and thus delivers 4K at an effective
refresh rate of 60Hz. It’ll also run as a
native 1080p projector at up to 120Hz.
The big question is whether this
approach delivers what it promises,
namely a true 4K experience. Subjectively,
the answer is no. We’re pretty familiar
with the LCD approach to 4K pixel-shift
technology, and this DLP take is only
a marginal improvement. It remains
obvious enough when observing, for
instance, smaller-point fonts in Windows
that you’re not experiencing full 4K.
That impression is a lot less obvious
with high-quality 4K video content, which
looks far sharper and more detailed than
the 1080p alternative. But so does a pixel-
shift LCD projector. The fact remains,
though, if you want a true 4K experience,
there’s no substitute for a native 4K
projector. The only problem is that native
4K requires relative megabucks, while
you can snag this beamer for $1,200.
Of course, the UHD50 is not the only
pixel-shifting projector, so the question of
whether you should buy it comes down to
its broader capabilities and performance,Affordable 4K projection, DLP-style
Optoma UHD50
7
verdict Optoma UHD50Oscar winner A big step up
in detail versus 1080p; good
for gaming.
GOlden raspberry Still not true 4K;
some image quality issues.
$1,199, http://www.optoma.comSPECIFICATIONSprojection
Technology
DLP
resolution 3840x2160 (1920x1080 DLP
chip with pixel shift)
brightness 2,400 lumens
contrast Up to 500,000:1
color wheel RGBRGB six-segment
Throw ratio 1.21–1.59
Optical Zoom 1.3x
refresh 4K @ 60Hz, 1080p @ 120Hz
inputs HDMI 2.0 x1,
HDMI 1.4a x 1, VGAwhich are mixed. We’re not blown away
by the quality of the UHD50’s optics.
For starters, the lens shift is limited to
the vertical axis. That’s compounded by
slight imperfections in image geometry,
in our sample unit at least, which make
attaining a perfect setup elusive.
This projector also suffers from
a “light border” around the projected
image. It’s substantial in size rather than
intensity, and only a minor distraction,
but unwelcome all the same. Elsewhere,
in SDR mode, contrast is good rather than
spectacular. Still, for this reviewer, who is
sensitive to the rainbow effect associated
with DLP projectors, the good news is that
there’s little of that in evidence. Another
upside involves gaming. Along with 4K at
60Hz and 1080p at 120Hz, it looks great in
game at an interpolated 1440p.
Less impressive is the UHD50’s HDR
implementation. Like a lot of so-called
HDR PC monitors, better to think of
this as a projector that can process an
HDR signal rather than one that can do
full justice to HDR content. The UHD50
doesn’t dramatically move the game
on—it’s a decent all-around projector,
and we’d take it over a 1080p model, but it
doesn’t achieve the holy grail of a full 4K
experience on the cheap. –Jeremy Lairdin the lab
84 MAXIMUMPC aug 2019 maximumpc.com