Optoma UHD51A Ultra HD DLP Projector Review

In addition to 3840×2160 pixels from a .47-inch DLP chip, it has HDR10, 3D, and 2400 lumens output. You can connect to one of the two HDMI 2.0 inputs or play the latest content through USB or Wi-Fi with its built-in media player. No sound system? No problem. The UHD51A boasts two five-watt speakers in its compact chassis. In addition to a convenient remote, it can be controlled with Amazon Alexa or Google Assistant.

Optoma has been in the projector game since 2002, always offering the latest display technologies. Recently, I’ve reviewed several Ultra HD DLP models based on a .47-inch chip from Texas Instruments that brings 3840×2160 resolution and HDR to a very attractive price point. At this point in time, there are two types available: one has an RGBW color wheel and high output, while the other utilizes an RGBRGB part for better color accuracy and a little less brightness. The Optoma UHD51A is in the latter category. Similar to the BenQ HT2550 and ViewSonic PX727-4K, it offers 2400 lumens and sets itself apart with voice control courtesy of Amazon Alexa and Google Assistant. It also offers HDR10 and 3D support. A compact and lightweight chassis, along built-in stereo speakers, enables easy portability. In addition to the latest HDMI 2.0 inputs with HDCP 2.2 content protection, you can play media over Wi-Fi with a USB dongle, or from a thumb drive. It’s an impressive package for less than $1700. Let’s take a look.

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The UHD51A uses the same design as other Ultra HD projectors in this price category. A single .47” DMD is used with an RGBRGB color wheel. The native resolution is 1920×1080, but it employs an optical shift to produce 3840×2160 individually-addressable pixels. This approach differs from JVC’s and Epson’s displays which use a refraction module in the light path to shift each pixel twice. The DLP version uses its rapidly oscillating mirror array to accomplish the task without additional hardware. Not only does this result in higher light output, the single-chip design provides better image clarity. Viewers will be hard-pressed to tell the difference between this projector and a native 4K design, except for the price of course. Native 4K will cost you at least $5000 or more.

The chassis is black and finished in a combination of glossy and textured surfaces. A thin metal strip runs around the beltline and forms a ring around the lens, which is offset to the right. Ventilation is generous and covers both sides and the front. Heat will not be a problem here and luckily; the internal fan is very quiet. Even in the lamp’s bright mode, you can barely hear it. Optoma rates the noise level at 28db, or 25dB in the Eco mode. There is a little light leakage around the lens cavity and from the side vents. It did not impact image quality in my completely-dark theater.

The UHD51A is the only projector in this category to offer vertical lens shift, accomplished with a small mechanical dial on top. The adjustment range goes from 100 to 115% above the lens axis. That means when unshifted, the bottom of the image falls at the lens’ centerline. You also get a 1.3x zoom to size the picture. That and the focus are controlled by lens barrel adjusters. Movements are reasonably precise though I found the shift dial had a little play in it. To level the picture, the three feet on the bottom are threaded. And you’ll need to tweak them because there is no keystone correction included. This isn’t an issue for me because I never use this resolution-reducing feature. But it might be a problem for some who cannot mount the projector perpendicular to the screen.

On top are the aforementioned lens controls along with buttons for menu navigation, power, and a home key for the integrated media player. Status lights monitor power, lamp, and temperature values. Also here is a large IR receiver which, along with a second sensor on the front, make for a very responsive remote.

That unit is not your typical handset, looking more like something that would come with a streaming box or Apple TV. It isn’t backlit, but it has so few buttons, you’ll quickly memorize their functions. In addition to power, there are menu controls and a home key to open the main interface. That’s where you can change inputs or select one of the streaming sources, Wi-Fi or USB. You also get volume control and a picture mode selector. The buttons click nicely, and the small wand is finished in a grippy plastic that feels soft in the hand.

The back panel features two HDMI 2.0 inputs with HDCP 2.2 content protection. You also get a VGA port which can connect to older computers, laptops, or be used with a breakout cable for three-wire component sources like VCRs and DVD players. Control is possible through an RS-232 port and there is a 12v trigger output for things like motorized screens. The USB ports can provide power and accept Ultra HD video files from thumb drives or external hard disks. Audio support is provided by 3.5mm in and out jacks along with an optical digital output. You can also use the built-in stereo speakers. There are two, driven by five-watt op-amps.

Pressing the remote’s home key brings up an interface that looks a bit like the smart screens seen on many flat panels. You can stream content over Wi-Fi, which requires an additional dongle. Or you can load content from a USB-connected device. This is also where you select traditional video inputs. The UHD51A also supports 3D content, though you’ll have to disable the Ultra HD feature to see it. That’s accomplished by turning on 3D in the menu. No glasses are included but you can use aftermarket ones like those from Xpand, available online for around $40.

I installed the UHD51A on a small table in front of my seating. This is a common configuration for portable projectors. They’re designed to be set up on a coffee table to throw the image on a wall or roll-up screen. Squaring up the picture is easy with the lens shift and zoom adjusters. Focus is firm and precise, and I had a razor-sharp picture on my Stewart StudioTek 130 within minutes. Sources were connected to the HDMI 1 input with a Monoprice Redmere cable. For the viewing tests, my OPPO UDP-203 demands a more robust cable so I used a 30-foot Bluejeans part with 22AWG wire. It’s not much more flexible than the average garden hose but it will support 18Gpbs over a long run.

The menu flies out from the left side of the screen and cannot be moved. It’s placed well for most test patterns though I found it blocked my view of a grayscale ramp I use for setting brightness. It’s arranged into five submenus starting with Image Settings.

There are six picture modes for SDR plus HDR and 3D modes. When an HDR signal is present, there are four additional presets found in the Dynamic Range sub-menu. You can also unlock ISF Day and Night modes with a remote code. After the usual brightness and contrast sliders, there are seven gamma presets, a color management system, and two-point grayscale adjustments. Everything works well and with precision except the RGB Bias controls which are too coarse to be useful. Each click results in a significant change. Fortunately, I only had to change the gains to achieve excellent grayscale tracking. You also get an option called color space which selects RGB or YUV input. RGB can be left to Auto or set for PC (0-255 levels) signals. Auto corresponds to the correct video range of 16-235 and is the way to use the UHD51A’s full dynamic range.

The lamp settings are found under Brightness mode and include Eco and Bright options. I looked for a dynamic option and found a separate control called Dynamic Black. This usually indicates a low-end gamma adjustment that is better left off. In this case however, it more than doubles contrast without clipping detail. In my observation, it appears to vary bulb output. While it improves the image for both SDR and HDR content, it is not the equal of a mechanical auto-iris. This is something that no projector in this category has and I miss it. Hopefully, the next generation of 4K DLPs will bring it back.

Setting up Alexa integration begins by creating an account with Optoma’s Device Cloud service. Once you generate a device code, you can register your UHD51A. After you’ve created skills for it (Alexa users will know what that means), control of power, input, and volume is enabled via voice commands.

To calibrate the UHD51A, I selected Reference as the best starting point, set gamma to 2.4, and made a few changes in the CMS and gain controls. Settings are specific to signal type, so you’ll want to set your source for a single output format to avoid performing multiple calibrations. With setup complete, it’s time for the fun part of the review.

In my recent reviews of Ultra HD projectors, I’ve played movies that I own in both 1080p and Ultra HD formats. This allows for a meaningful comparison and easily answers the question I get most often, “Does 4K really make a difference?”

Comparing the two versions of Star Wars, The Last Jedi, it was immediately apparent that the UHD51A’s principal strength is Ultra HD/HDR material. The 1080p version just didn’t have the same impact, and the difference lies mainly in contrast. Even though projectors can’t display HDR the same way flat panels do, the modified tone-mapping makes a huge difference. Even the opening menus look far better. The final battle scene takes place on a planet covered in red salt. I didn’t see any significant difference in color, but the sharper detail and deeper blacks were obvious.

My initial comparisons with Dynamic Black made it clear that it should be left on all the time. It improves contrast and doesn’t clip highlight or shadow detail. I started with gamma set to 2.4 but found different films looked better on different gamma settings. Some worked well at 2.4 while others preferred 2.2. HDR content looked best with the option set to Film. You’ll also want to leave the HDR picture mode on Standard. The other options make the picture too dark or too light.

Jumanji, Welcome to the Jungle is rife with deep shades of green and lots of nicely-textured earth tones. Ultra HD really brings the tactility of the jungle to the fore and sets the characters solidly in the foreground. This presentation really makes one ask, “why do we need 3D?” It’s hard to imagine better clarity or depth. The Rock’s skin tones, along with every drop of sweat and particle of dirt, pop right out to where you can almost feel them (eww).

To check out a few dark scenes, I turned to Thor Ragnarok. Early in the film Thor and Dr. Strange have a meeting in a dusty museum that is barely lit from a few small windows. The 1080p version never dropped below a medium gray. The Ultra HD disc managed deeper blacks and better detail though it was never a true black. The UHD51A, like its competition, would really benefit from a mechanical iris. Turning on Dynamic Black helps contrast quite a bit, but it won’t replace a good auto-iris.

To test the UHD51A’s color accuracy, I measured from the lens with an X-Rite i1 Pro Spectrophotometer fitted with a diffuser attachment. Luminance readings were taken with a Spectracal C6 tri-stimulus colorimeter facing a 92” diagonal Stewart Filmscreen Luminesse with Studiotek 130 material, gain 1.3, at a 10-foot distance. Patterns were generated by an Accupel DVG-5000 and controlled with CalMAN, version 5.8.

The UHD51A comes from the factory set to its Cinema picture mode. It’s reasonably close to D65 with a gamma just below 2.2 and accurate Rec.709 color. But the Reference mode is slightly better in all respects. That’s where I started my tests.

Grayscale errors run slightly green from 50% on up but this is barely visible. Gamma is also a tad light but again, it isn’t a concern. I would classify the UHD51A as not needing calibration. There is room for improvement though. The gamma presets and RGB controls are there and one shouldn’t leave any performance un-utilized.

Calibration removes all visible grayscale errors. Though there is a green spike at 10%, I could not see it in the test pattern. Changing the gamma preset to 2.4 gives the image a bit more depth and improves perceived contrast. Color looks better saturated as well. I recommend leaving Brilliant Color on setting 1. If you want to experiment with this option, calibration should happen afterwards. Every change of the setting throws grayscale off, requiring a readjustment.

In Reference mode, color measures quite close to target for both saturation and luminance. Red is a little under-saturated and there are hue errors in cyan and magenta. But these issues are not a factor in real-world content. With an average error of just 2.9487dE, you won’t see any problems. This is excellent performance.

After tweaking grayscale, changing the gamma preset, and making some changes in the CMS, the average error is slightly reduced. Secondary colors are now closer to their hue targets and red is a bit more saturated than before. Luminance levels are more balanced though they are all a tiny bit light. This is another inconsequential issue. I have no complaints about the UHD51A’s color accuracy. It is excellent, especially at this price point.

The UHD51A offers four HDR picture modes. They differ mainly in EOTF tracking. I measured them all and found Standard, the default, to be closest to the mark. All of them take the clipping transition too smoothly but this isn’t a grievous error. The main issue is between 40 and 70% brightness where there is a lack of red. Neutral tones look a bit cool here.

Adjusting the gain controls improves things a bit but the mid-tones are still too cool. The EOTF is unchanged. Actual content looks pretty good but other projectors I’ve measured are a little more accurate in this test.

The UHD51A, like its similarly-priced competition, is limited to the Rec.709 color gamut. To give the impression of more-saturated hues in HDR mode, it pushes the inner targets well past where they should be for accurate reproduction. The primaries are as much as 35% beyond their prescribed points. Is this a problem? Not necessarily. All HDR displays exhibit the same behavior to varying degrees. In my experience, only a handful of reference-level computer monitors have done well in this test. In the brightest content, you might see some detail clipping but for the most part, it’s not a big deal. Still, I’d prefer to see one of the HDR picture modes render a gamut that’s accurate at all points.

The DCI-P3 color test produces similar results. Mid-tones, where most content lies, are oversaturated. This gives the image plenty of pop and makes it easy to see the difference between SDR and HDR color. I suspect most users will enjoy the presentation and it’s a good compromise to live with until we have true DCI-P3 and Rec.2020 displays available in the consumer realm.

The UHD51A’s video processing is better at scaling than de-interlacing. 1080i content shows failures in the 2:2 and 3:2 test. If you plan to watch DVDs, it’s best to let your player handle that chore. I recommend setting it for 1080p output. Chroma resolution is excellent regardless of signal format. Even the 4:2:2 test showed no visible roll-off. To see above white and below black information, the Color Space options must be set to RGB 0-255. Otherwise, below 16 and above 235 will be clipped. This isn’t a problem and I’d rather utilize the entire dynamic range of the projector anyway by setting that option to Auto, which corresponds to RGB 16-235.

All luminance values are expressed here in nits, also known as candelas per square meter (cd/m2). For those needing a frame of reference, 1fL equals 3.43 nits, or 1 nit equals .29fL.

The UHD51A provides plenty of output for small to medium theaters or multi-use media rooms. After calibration in the lamp’s Eco mode, the peak white level is 88 nits with .1871 nits black and a contrast ratio of 470.1:1. Increasing the lamp power to Bright results in 132 nits peak, .2807 nits black, and 471.1:1 contrast.

Turning on Dynamic Black increases contrast by more than double. I measured 147 nits peak with .1441 nits black and a contrast ratio of 1021.4:1.

In HDR mode with the lamp on Bright mode and Dynamic Black on, I measured 224 nits peak, .1308 nits black, and 1711.7:1 contrast.

For maximum output, select the Bright picture mode. Here, you’ll get 336 nits peak, .2823 nits black, and 1190.6:1 contrast. The color temp is quite green and both shadow and highlight detail is clipped. This mode is best used in brightly-lit rooms.

In 3D mode, the UHD51A offers a respectable 22 nits white, .096 nits black, and 224.2:1 contrast. Crosstalk measures an extremely low .03%.

THE OPTOMA UHD51A ULTRA HD DLP PROJECTOR offers superb picture quality, Ultra HD, HDR, and 3D for just $1699. Its Alexa and Google integration set it apart from similarly-priced projectors.

I continue to enjoy the parade of Ultra HD projectors coming through my theater. It’s truly a wonderful time for video enthusiasts when we have our pick of excellent products from multiple manufacturers at prices thought unattainable just a few short years ago. The Optoma UHD51A delivers excellent performance and a razor-sharp picture for just $1699. While it costs a few bucks more than the competition, it adds Alexa and Google integration, a built-in media player, 3D, and lens shift to the feature list.

My complaints are minor ones. Its video performance boasts similar accuracy to others in the class and most users will be able to enjoy the UHD51A without incurring the cost or effort of calibration. Of course, those who take the extra step will be rewarded with a slightly better picture. Like the competition, Optoma has dispensed with a mechanical auto-iris in favor of bulb output throttling. While this approach improves contrast, I would rather have the iris. Perhaps a future generation of displays will add it back in.

I’ll finish up by stating just how compelling these Ultra HD DLP projectors are. When you play an Ultra HD Blu-ray at full 3840×2160 resolution with HDR, the experience is on another level from 1080p. Does 4K make a difference? It sure does. While it is still best seen on a flat panel TV, the UHD51A brings much of that feeling into the theater and onto the big screen. If you’re considering an upgrade, or building a new space for family movie night, Optoma makes a great choice. Highly Recommended.