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Alexa supported 4K Ultra HD projector

Immerse yourself in a world of Ultra HD. The UHD51A delivers the ultimate in smart home entertainment with impressive 4K cinema quality images and support for Alexa voice control. You can now enjoy accurate colours, crystal clear detail, and sparkling contrast for a stunningly immersive experience.

Alexa voice control provides instant setup allowing you to adjust the volume, switch inputs, launch content and more.

Packed with the latest technology and features, this compact UHD projector boasts High Dynamic Range (HDR) compatibility, HDMI 2.0, wireless, a built-in media player, IFTTT and PureMotion frame-interpolation processing which eliminates motion blurring or image judder. An RGBRGB colour wheel delivers 100% Rec.709 for accurate, true to life colour rendition - perfect for recreating the big-screen experience at home.


4K UHD resolution and HDR compatible
Amazing colour - accurate 100% Rec.709 colours, 2400 ANSI lumens
Voice control - Amazon Alexa supported device
Feature packed - Built in media player, Wireless and PureMotion

4K UHD Resolution

With over eight million pixels, Ultra HD 4K resolution brings four times more detail than Full HD, to deliver sharper, life-like images and richer colours - allowing you to sit closer to the screen and enjoy a more immersive experience.

4K UHD Resolution
HDR compatible

HDR compatible

Capable of receiving and displaying HDR meta data, Optoma HDR compatible projectors allow you to see far more detail and texture. Objects look more solid and life like and the extra detail creates a greater sense of depth. It’s like looking through a window.

Amazing colours

Amazing colours

Watch your movies, TV shows and play games with stunning colours in any environment. Optoma projectors provide reliable performance suitable for any content and environment. Our home projectors are capable of reproducing the Rec.709 colour gamut, the international HDTV standard to guarantee accurate reproduction of cinematic colour exactly as the director intended. Or more saturated colours for a punchy looking image, great for gaming and animated movies.

Vertical Lens Shift

Simplify installation with vertical lens shift, which provides a wider range of projector placement possibilities. This makes it easier to position the projector in your room and enables a wider range of screen size options.

Vertical Lens Shift


Using sophisticated frame-interpolation technology, advanced motion control processing eliminates motion blurring or image judder, even in high-speed action sequences.

Built in media player

Built in media player

Watch movies directly from your projector without the need of a laptop or PC by using the built-in media player. Simply copy your files to a USB stick and watch them on the big screen.

Full 3D

Full 3D

Optoma projectors can display true 3D content from almost any 3D source, including 3D Blu-ray players, 3D broadcasting and the latest generation games consoles.

Colour Management System (CMS)

Display accurate lifelike colours to best match your viewing environment. This unique feature provides you with the flexibility to fine-tune the colour settings for optimal precision.

Colour Management System (CMS)
ISF modes

ISF modes

This feature allows you to save your calibrated day and night mode settings for the highest possible viewing experience.



Most movies are shot at 24 frames per second (fps). To preserve the purity of the original image, Optoma projectors can accept high definition sources at 24 fps to display movies exactly as the director intended.

Integrated speaker

Integrated speaker

Complete your home entertainment experience with the convenience of a powerful built-in speaker for exceptional sound quality and an easy set up without the need for costly external speakers.



Use the USB-A port to power an HDMI dongle, such as Google Chromecast.



IFTTT (If This Then That) is a free web-based service that allows you to create chains of simple conditional statements, called applets. Applets are used to trigger events such as getting your projector to turn off when you leave the house.


EMEA standard warranty
EMEA standard warranty


Expert reviews

Tech Radar
October 2019

Being able to shout “play the movie!” at a voice activated projector, potentially installed in a bracket high above your head, seems like a sound move. 

Ultimately, while the Alexa features are fun (if a little perfunctory) everything about this the Optoma UHD51A performs exceptionally. At this price you’re going to be hard pressed to find a projector that can deliver this level of picture quality and this feature set more confidently.

The Optoma UHD51A represents a great shift in 4K projecting quality if you find yourself on a tighter budget. What’s on offer here allows even those with smaller living spaces and more modest bank balances a taste of the home cinema high life.

Just Creative
September 2019

One of the key selling points that Optoma makes with its UHD51A projector is its Alexa integration which lets you control the projector with voice commands using a smart speaker. While it can be a bit gimmicky at first, after a while you get more accustomed to not searching for a remote during a presentation. While the addition of 3D support requires you to have Active DLP Link glasses, the picture that the UHD51A projects a rich and sharp image.

Live for Films
August 2019

As with all Optoma projectors, it is extremely easy to set up.

Looking at Blu-rays in 1080p the projector gave it an extremely clear and sharp image. Looking at 4K images I was blown away by the detail on view. The test footage I watched included visuals from Machu Picchu which made you feel as if you were almost there.

The projector brightness is 2400 lumens but it did seem brighter and there was no problem watching images during the day. While either watching movies, streaming TV shows (Stranger Things on the big screen) and playing video games, the projector performed admirably.

If you are after a decent 4K projector at a fairly decent price, then this could well be the one for you.

4Rays Tech
June 2019

Optoma UHD51a packs 4K, 3D & HDR. It’s bigger, it’s brighter, it’s sharp, the details are great coming under $1500. A great treat for HDR fans in 2019.

The quality is absolutely spot on.

Straight out of the box, the colours overall are quite soft and they are very accurate.

Should you get this instead of the 4K TV? Definitely yes!  You get a lot of colours. You get a big 150” screen. You get a sharper colour range. You get bigger dynamic range.  You’ve got a lot of controls.

It’s a good multi-purpose grand scale 4K projector experience.

Home Cinema Choice
April 2019

UHD51A’s image quality immediately gets a thumbs up. With both HD and UHD sources, there are admirable levels of detail on screen.

The projector is HDR compatible and makes a good fist of high dynamic range content.

It’s easy to be impressed by Optoma’s UHD51A. It’s a well built, high-performance 4K projector, bolstered by topical smart home functionality.  Image quality is generally great, and its 3D performance entertaining.

November 2018

Alexa can turn on your home cinema projector, but that’s not the only reason to love this UHD-capable Optoma.  This compact projector doesn’t just look crystal clear with 4K content, it’s also compatible with 3D too. TVs may have given up on the third dimension, but you can carry on watching your 3D Blu-rays on the bigger screen.  The UHD51A is bright, with cinematic contrast.

July 2018

The UHD51A works with Alexa, making it smarter than any other 4K UHD projector under $2000 to date. Count the UHD51A as one of the best sub $2000 4K capable projectors on the market. If the features and other trade-offs align, it will be your best choice for the money. It definitely earns a Hot Product Award.

Nerd Techy
June 2018

The Optoma UHD51A is a fully modernized projector with essentially every feature you want. What it brings to the table is essentially all of the latest and greatest improvements and technology standards to video quality. It has things that might ordinary sway you into choosing a TV over a projector, like high dynamic range (HDR), 4K UHD resolution, and a wide gamut of vivid colors. And it has the same voice-assistant and streaming power that you’d find on a modern smart TV. Combined with every advantage that you use a projector for in the first place, the Optoma UHD51A has plenty to offer.

For watching your favorite shows and movies, the Optoma UHD51A has all the essential ease-of-use kind of features people want from their home theater.

Owner reviews

Verified Review
A beauty of a projector
Ferdie K, London : United Kingdom, December 2018.Purchased from Amazon
We bought the Optoma UHD51A projector when we moved house as we work in the entertainment industry and for less than the price of an equivalent TV, we got our hands on an incredibly capable projector taking up very little room on a shelf above our sofa. Setting up was relatively simple - once viewing distances had been calculated, it only took a couple of minutes to get the UHD51A fired up, the fine zoom adjusted and the focus sharpened. Once calibrated, the UHD51A kicks out a beautiful and deep 4K image. On our 92in screen viewed from approximately 120in away, the “faux” 4K image is barely distinguishable from the “true” 4K of far more expensive models, HDR content (which is automatically detected by the projector) is rich and realistic, and even lower resolution and SDR content is presented beautifully. The image isn’t the very brightest, so daytime viewing is a little washed-out as you might expect, but with the current limitations of DLP rgbrgbrgb chip technology, it’s as good as you can hope for. Picture modes work a treat, with built-in presets and user-defined ones easily accessible and switched. Optoma’s puremotion frame interpolation is subtle and useful, making most tracking and fast-moving shots smoother than you might expect. Rainbow artefacts are occasional, but pretty minimal, too, which is a relief. Sound is surprisingly good - the projector of course makes some noise, but it’s quieter than many other models out there, and the internal speaker puts out a very listenable sound. It’s not something I would choose to use to listen to a film’s soundtrack, but it will do the job for casual use, or for that time when your AV system isn’t working properly. The menu is, for the most part, easy to navigate and understand, although there are a couple of small niggles. The main one of those is that if the device you have connected is outputting at 4K (ie a new Apple TV, or an Amazon Fire TV 4K, or even a PS4 Pro or a UHD Blu-Ray player), then there is absolutely no way to activate 3D on the projector. This is not explained anywhere in the manual or online - it took contacting Optoma’s support team and asking for help in forums to discover the fix: you must change the setting on your connected device to 1080p (usually at 50hz) before the 3D option is selectable on the projector. It’s doable and not the end of the world, but Optoma really should make this clear either in the manual or in the menu system. The on-board media player is simple to navigate and has very good compatibility indeed, with most file formats accepted and played without fuss (though 3D doesn’t seem to be an option here, disappointingly). There is quite a significant issue with the USB inputs, though: the UHD51A currently only accepts USB drives formatted in FAT or FAT32, which means that the largest file that you can play on the projector is 4gb. I work with and am sent a lot of 4K footage, and those files are often far bigger than 4gb, so currently they are unplayable on the UHD51A. This is something that Optoma could easily fix with a firmware update, and I sincerely hope they do so ASAP as it’s rather an important feature to someone like me. On the subject of firmware updates - the UHD51A’s small wireless adapter works well, with screencasting and Alexa operating pretty seamlessly (though the Alexa skill could do with some development as its implementation is pretty basic so far). Another relatively small niggle is that the projector has two ports for its one wireless adapter, and they both have different functions. For example, one port deals with firmware updates and wireless screencasting, whereas the other deals with another type of OTA update and Alexa operation, so you can’t screencast and use Alexa without switching the wireless adapter between ports, meaning you have to mess around with the body of the projector - something that nobody particularly wants to have to do much once they’ve set up their system. Overall, I’m delighted to have purchased the UHD51A - when it comes to projectors, picture quality is of course what matters, and in that regard this projector is the best I’ve experienced in its price bracket. Most of the niggles I’ve encountered with the software are relatively minor, and even the problematic USB formatting situation could be easily remedied with a firmware update, and hopefully Optoma will address that in the near future. If and when they do, I’ll update this review. At its price point, I wouldn’t hesitate to recommend the UHD51A - I have a feeling it’ll provide us with years of great entertainment.
Verified Review
Great projector
Allan Sinclair, Wishaw, North Lanarkshire : United Kingdom, December 2018.Purchased from Amazon
I had been thinking of buying an Optoma UHD51a projector for quite some time after reading many reviews on it. I already owned an Optoma HD230x projector and wanted to upgrade it. When I seen the deal Amazon had on this projector in their Black Friday deals it was too good not to buy it. On receiving it I immediately set it up and I have to say it did not disappoint. The colours are much brighter, the image sharper, I absolutely love it. I am now looking to buy as may 4k blue ray discs as I can to get the full benefit of my projector. I would recommend this projector to anyone who is looking to buy a 4k projector.


Display technology
UHD (3840x2160)
2,400 lumens
Contrast ratio
Native aspect ratio
Aspect ratio - compatible
Horizontal scan rate
31 ~ 135Khz
Vertical scan rate
24 ~ 120Hz
Screen size
0.87m ~ 7.68m (34.1" ~ 302.4") diagonal

Lamp info

Light source type
Lamp watts
Lamp life hours (up to)
4000 (Bright), 15000 (Dynamic), 10000 (Eco)


Throw ratio
1.21:1 ~ 1.59:1
Projection distance (m)
1.2m - 8.1m
Zoom type
Focal length (mm)
12.81 ~ 16.74
Lens shift
Vertical +10%
Native offset


Inputs 2 x HDMI 2.0, 1 x VGA (YPbPr/RGB), 1 x Audio 3.5mm
Outputs 1 x Audio 3.5mm, 1 x S/PDIF, 1 x USB-A power 1.5A
Control 1 x USB-A service, 1 x RS232, 1 x RJ45, 1 x 12V trigger, 1 x USB-A reader/wireless, 1 x USB-A wireless Alexa


Noise level (typical)
PC compatibility
2D compatibility
480i/p, 576i/p, 720p(50/60Hz), 1080i(50/60Hz), 1080p(50/60Hz), 2160p(50/60Hz)
3D compatibility
Side-by-Side:1080i50 / 60, 720p50 / 60 Frame-pack: 1080p24, 720p50 / 60 Over-Under: 1080p24, 720p50 / 60
Full 3D
Security bar, Kensington Lock, Password protected interface
OSD / display languages
10 languages: English, French, German, Italian, Japanese, Portuguese, Russian, Chinese (simplified), Spanish
Operating conditions
5°C ~ 40°C, Max. Humidity 85%, Max. Altitude 3000m
Remote control
Backlit home remote
Speaker count
Watts per speaker
In the box
Lens cap
AC power cord
Remote control
Basic user manual
WUSB (wireless USB dongle)
Operating system compatibility
Windows 7 / 8 / 8.1 / 10, MacOSX 10.9 +, Android 4.0+, iOS 8+
Optional wireless models


LAN - control
LAN - wireless networking


Power supply
100 ~ 240V, 50 ~ 60Hz
Power consumption (standby)
Power consumption (min)
Power consumption (max)

Weight and dimensions

Net weight
Dimensions (W x D x H) mm
392 x 281 x 118
Verified owner

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