Posted on November 11, 2020 By Phil Jones
LG BU50NST 4K Laser Business Projector Review – Special Features: Laser Light Engine, UHD, Smart Wireless Connections, DICOM Simulation
The BU50NST is based on DLP (Digital Light Processing) imaging technology with laser/phosphor illumination. This approach delivers an exceptional product lifespan and vivid images for larger picture sizes in demanding spaces. Additionally, Laser Phosphor operates at a faster speed, with a much wider range of output power than a lamp-based system.
The combination of Laser Phosphor illumination combined with DLP imaging enables the BU50NST to provide a range of solutions with exceptional value, performance, durability, and flexibility.
Due to the characteristics of the laser light source, a much wider range of light output is available. This is a significant advantage over lamp-based systems allowing for incredible flexibility when used in spaces with variable lighting, which is a reality in most professional AV applications. Lamp-based systems are limited not only in maximum light output but also in the minimum output, which that same lamp could produce with proper characteristics. A lamp-based system can only dim by 20%, which is typically not enough to properly compensate for usage in both dark and bright environments.
Choosing the BU50NST eliminates routine lamp replacement and maintenance concerns in general. With an illumination rating of up to 20,000 hours, five to ten lamp changes will typically be avoided along with the associated labor costs. Because the illumination is designed to last the life of the product, it’s convenient to place the unit in difficult to reach locations like creative museum displays or high ceiling installations in auditoriums.
There are three modes to adjust the brightness output of the laser light source. These modes are labeled in reference to their energy savings:
• Minimum – Full laser light source brightness
• Medium – Lowers laser brightness to extend the light source life and decrease the fan noise
• Maximum – Lowers laser brightness to the lowest level for darkest environments and least energy consumption
LG has made a strong entry into the Business Soutions market, offering this projector with a remarkable combination of business-friendly features. Most notably, there has been an increased demand for highly detailed images for some situations especially large images or those viewed from a close distance. The BU50NST includes UHD resolution by utilizing DLP with XPR technology from TI.
While UHD projectors have been available with other imaging technologies, these have often come with increased cost (significant in the case of large 3-chip DLP). DLP is the most widely used imager for good reasons. With good uniformity, excellent durability, and color accuracy capability, DLP is broadly acknowledged as the preferred choice for the most demanding imaging solutions such as military and racing simulators, commercial cinemas, and amusement park attractions.
With the introduction of XPR technology, TI has enabled projector manufacturers to design cost effective solutions such as the BU50NST with all of the benefits of DLP. XPR leverages the immense speed of the DMD (Digital Micro-mirror Device) to process pixels faster than the rate of the video signal- exceptionally faster! This speed is how DLP can utilize one imaging chip to create multiple colors as well as multiple pixel locations. In the case of the BU50NST, there are four individual pixels shown on screen from each of the DMD’s tiny mirrors. In the earlier DMD designs, the pixel would only pivot on or off using one hinge and axis. The XPR chip tilts in 4 directions and operates fast enough for our eyes to see all the pixels and perceive the entire image all at once. It is truly amazing that it works at all, let alone that it delivers the most durable option possible with DLP DMDs having an MTBF of 100,000 hours. DMDs rarely fail and don’t deteriorate in image quality over their lifespan, unlike competing technology.
While the BN50NST could be considered budget friendly, the inclusion of optical lens shift adjustment in both horizontal and vertical axes provides the proper method to adjust the position of the image compared to the installed location. The ability to make this adjustment optically rather than by using digital keystone or other digital geometry correction provides the best possible image. By using larger lenses than absolutely required, the position of the image passing through the lens can be adjusted by moving the lens and image sensor relative to each other inside of the projector. In this case, the adjustments are made by concentric dials on the side each of which allows for the movement of the image on screen, one for vertical and the other for horizontal.
By doing this you can avoid twisting the projector body towards the screen location if they are slightly misaligned. When a projector is placed so that it is askew to the screen, light from the image does not travel equidistantly to each edge so as it travels farther, the image continues to enlarge. This is what produces trapezoidal images rather than rectangles. Have the projector tilted in two directions and it gets more complicated. Ideally, the projector can be placed so that its lens is perpendicular to the surface of the screen both horizontally and vertically. In this way, the image will be a perfect rectangle as long as the screen is flat. The process to use lens shift is quite simple- after assuring the image is a perfect rectangle at a smaller than the required size, use the lens shift to move the image to the center of the screen horizontally, zoom out and adjust the height of the image to match the screen height.
In most cases, professional grade projectors will allow for a projector installation location of approximately at the top of the image rather than fully centered on the screen. LG provides enough shift to place the projector at the top or bottom of the screen. If a position off-center horizontally, is required there is also horizontal shift but the adjustment will always affect the range of shift in the other direction since lenses are circles.
If the position of the projector needs to be outside of the optical shift range, then the excellent capabilities of the built-in 12 point warping will provide further adjustment albeit at the loss of pixels and the introduction of distortion, which can be visible in perfectly straight lines such as in spreadsheets or program guides or other grids. Standard video or photo content will show less noticeable distortion.
In addition to the usual Picture modes, LG has included a DICOM Simulation mode intended to display images approximating the DICOM (Digital Imaging and Communication in Medicine) used with B/W medical imaging (such as x-rays). This mode optimizes black/gray/white detail with a custom gamma curve. Although the projector uses the DICOM name, it is not a medical device and should not be used to diagnose via displayed images. Instead, the DICOM Simulation mode is intended for education/classroom teaching purposes.
LG has entered the ProAV projector market with a combination of features that seems to fire on all cylinders. While UHD, laser & DLP are hallmarks of this design, the feature set is primarily born out of LG’s extensive experience with smart flat panel TVs. This includes several “wireless” capabilities for audio, video, and networking.
Quickly connect the BU50NST to a Bluetooth source such as a smartphone for audio playback through the internal or connected audio system as well as the option to connect a Bluetooth audio device such as BT headphones or speakers for the playback of all sound processed by the projector (embedded on the HDMI). I was able to easily connect my BT headset for private listening and choose this option as my Sound Out setting.
In today’s world, having Wi-Fi built into devices seems to be the norm. However, this is not common on video projectors, with many offering no option or requiring the use of a USB dongle. Having wireless networking onboard allows for additional flexibility to connect to the infrastructure network.
While not a wireless connectivity option, per se, this underlying capability empowers access to content on the web quite easily as well as providing the GUI for accessing media and files for playback from USB. When connected to a robust Wi-Fi network, WebOS browser will provide access to web pages and media from YouTube or Netflix as examples. Unlike the WebOS many are familiar with found in LGs popular Smart TVs, the WebOS on the projector does not offer apps to content providers so the browser is the only option.
While the back panel is equipped with 2 RJ45 connections, (1-ea HDBaseT, LAN) if you are interested in using the MiraCast capability, you will need to connect to the wireless network in order to use this function.
In my set-up at home for this review, I was originally connected using the LAN jack and an Ethernet cable only. However, I was not able to get MiraCast functionality to work without using the Wi-Fi connection on both the projector and laptop and even then it was notably unpredictable. I did successfully connect via the Wi-Fi in my router as well as by connecting both the laptop and projector to the same Wireless Access Point.
Unfortunately, LG offers little support for anything other than Windows 10 computers (Windows 7 & 8 can connect via WiDi but I did not test this). Mac users will need another option to display their screen wirelessly as AirPlay is not supported. Users of Android and iOS can download the LG TV Plus app which is designed primarily for use with LG consumer TVs but also works well here, providing access to photos, videos, and music on your mobile device. This function uses DLNA and renders the content on the projector as part of the WebOS, it functions well as long as the appropriate network connections are in place.
While I did see the projector listed as a casting option from Chrome or Netflix for example, the content was not able to be displayed in these situations. This leaves little functionality for the display of wireless content in reality and in an enterprise application, it would not likely be a viable option.
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