Decades ago, my middle school math teacher was a master at providing real-time depictions of his thought process using a grease pencil on transparencies placed on an overhead projector. This timeframe was also an era when actual film projectors were occasionally wheeled into a curtained classroom to provide a (mostly) relevant lesson. The presentation of information in an instructional or learning environment has always relied on visualization technologies. Modern video projectors enable educators in classrooms of all sizes to easily incorporate digitized information into lessons, providing a more immersive, sometimes interactive, big-screen presentation at prices that won’t break the budget.
Solid-state Light
There are several factors to consider when deciding which projector will provide the best visual experience for a learning environment. For regular, daily use, a projector’s light source is crucial to its operation, and solid-state laser or LED illumination is a must-have feature compared to models that use traditional lamp modules. Most lamp-based projectors will require a replacement module after every 3,000 to 5,000 hours of operation. This cost can be a significant fraction of the projector’s original price, adding to the total cost of ownership. The typical laser or LED projector is rated for at least 20,000 hours of use until it reaches half its original brightness and up to 50% longer if not operated in its brightest mode. Laser/LED-based projectors also offer nearly instantaneous startup, making them operationally ready to go without any warm-up time.
The ideal classroom projector will also provide ample light output to overcome some daylight or room lighting. For example, a 100-inch projected image in a moderately lit room calls for a projector rated for at least 3,500 to 5,500 ANSI lumens of light output. The ViewSonic LS630W is an example of an affordable ($750 street price) laser projector with a claimed output of up to 4500 ANSI lumens. The LS630W offers flexible installation options, and its lens design requires a distance of about 8.3 feet to 10.8 feet to produce a 100-inch image.
More Pixels
The resolution of a projector will affect the clarity of text and other fine details. A 1080p screen resolution or higher has become the minimum standard for many educational installations. The aforementioned ViewSonic laser projector has a native resolution of about half that of 1080p (1,920 by 1,080 pixels). The company’s step-up model, the LS740HD, features a similar design but increases the resolution to 1080p and offers slightly more brightness at a street price of about 30% higher ($980).
For presentations that benefit from a wider aspect ratio than 16:9, support for 21:9 is becoming an increasingly common feature in classroom and office projectors. This wider picture format makes it easier to display two application windows side by side, and it’s more similar to the shape of most classroom whiteboards that can double as a projection screen surface. Wide view displays are also gaining support with popular group meeting applications, such as Microsoft Teams Rooms (Front Row layout) and Zoom Rooms.
The Christie Digital HS Series is the ultimate expression of laser projectors supporting a 21:9 aspect ratio. The HS Series features native 4K UHD resolution (3840 x 2160 pixels) and light output options ranging from 7,000 to 22,000 ANSI lumens, depending on the model. Its commercial-grade design, up to a 5-year warranty, and a wide selection of available lens options, including an ultra-short-throw (UST) design, are factors contributing to the higher cost of the HS Series (starting at $21,800) compared to other projectors in this article.
Another 21:9 aspect ratio supporting projector, which is a fraction of the cost and a fifth of the weight of the Christie HS Series, is the BenQ LK935 ($4,500). The LK935 keeps costs low with a single-lens option that can produce a 100-inch 16:9 image from 9.8 feet to 15.8 feet away from the screen. Its laser light engine is rated for up to 5,500 ANSI lumens and provides 4K pixel resolution. BenQ also offers a short-throw variant of this projector, called the LK936ST ($4,900), which can produce a 100-inch image from a distance of about 5.9 feet to 6.5 feet from the screen.
The Optoma ZK708T ($5,000 street price) is a 4K and HDR-compatible projector that provides up to 5,600 ANSI lumens of laser-based light output. The ZK708T’s dust-tight optical engine enables continuous, 24/7 use. However, Optoma recommends at least 30 minutes of downtime for the projector every 24 hours to extend the life of the projector’s laser light source, which is claimed to last an impressive 30,000 hours. The projector’s 1.60:1 zoom lens allows for a 100-inch image from a throw distance of 8.75 to 14.0 feet. Assisting with setup in less-than-ideal locations, the ZK708T features a 4-corner warping function and auto keystone correction, allowing you to quickly square up the image when the projector is not perpendicular to the projection surface.
Avoiding Artifacts
The projectors mentioned in this article (so far) use Texas Instruments’ DLP (Digital Light Processing) technology, which features a digital micromirror device (DMD). The DMD is a chip with an array of individually actuated microscopic mirrors that modulate the brightness of each pixel by rapidly switching between an angle that reflects the source light through the projector’s optical path or away when dimming the pixel or displaying black. The aforementioned DLP projectors are all single-DMD designs that sequentially display the primary colors (red, green, and blue) quickly enough for us to perceive the result as a full-color video image. There is a related artifact with projectors that rely on sequential color display, called color breakup or the “rainbow artifact,” which some people are more sensitive to. More easily observed in highly contrasted video material or when quickly scanning your eyes across the projection screen, DLP projection manufacturers have worked to minimize these artifacts by increasing the rate of sequential color presentation.
The solution to eliminate color breakup in video projection is to use a three-chip system that simultaneously processes the primary colors. Three-chip DLP projectors like those used in commercial cinema typically cost as much as a modest house. However, they can process the primary colors simultaneously, increasing the apparent brightness of all displayed colors.
While DLP is considered a very robust projection technology, the price of its 3-chip options starts in the five figures. Other multi-chip projection technologies offer more affordable options for classrooms, homes, and offices. Among the most popular of these three-chip color projection technologies is the Epson-developed 3LCD.
When a local public library requested help selecting a new projector for in-house and off-site presentations, I learned that the staff was handling the setup and day-to-day use of the projector. They also complained that their old projector had compatibility issues with an Apple MacBook they used frequently. For a few good reasons, I selected an Epson PowerLite L210SF with 3LCD technology for them.
The L210SF provides up to 4000 lumens of light output and native 1080p imagery – a commonly used resolution with enough pixels to produce a detailed image in the 80- to 130-inch size range. For the 100-inch portable screen they used, the throw distance calculations for the projector’s short-throw lens system placed it 40 to 55 inches away to fill the entire screen area. Other variants are available for longer-throw installation applications. This distance was ideal for their typical setup, and it’s always a good reminder to consult the projector manufacturer’s online calculator to verify that a particular unit and its lens option will perform as desired.
The Network Connection
Every projector I’ve mentioned in this article features network connectivity that enables browser-based control, simplifying remote configuration, troubleshooting, and integration into the classroom. Most projectors listed here are also compatible with third-party network control systems, such as Crestron and AMX, which can simplify the instructor’s day-to-day use in a permanent installation.
The Epson L210SF mentioned above does not support third-party control. However, it integrates wired and wireless networking options, along with free software provided by Epson. These apps allow users to interact with the projector over a local network connection and include tools like group-based screen sharing. The L210SF also features PC-free direct file support for images and videos on USB storage devices.
Advanced Interactivity
If adding interactivity to the projected image enhances your classroom’s engagement, a projector like Epson’s BrightLink 1485Fi ($3,100 street price) features PC-less whiteboarding using infrared-tracked interactive pens with selectable line colors and thicknesses. The 1485Fi also includes a bar-like Touch Unit installed above the whiteboard or screen, enabling the presenter to use their fingers instead of a pen to annotate images or draw. The Touch Unit also features a mouse function, allowing the instructor to scroll and zoom content shared from a locally networked computer using hand gestures on the projected image. Epson also provides a handy online resource for educators for its BrightLink technology, including video tutorials and setup guides.
Management and Maintenance
When shopping for a projector to share ideas with a group, consider who will be responsible for caring for and maintaining the projector over its lifetime. A protective bag or case is a worthwhile investment if it’s a single projector that travels from location to location. An appropriate storage container is also handy for stashing essential accessories, such as a remote control or cables.
Excessive heat shortens the lifespan of any projector. Many projectors incorporate air filters that must be checked, cleaned, or replaced periodically. I also recommend regular inspections of the projector’s lens for dust buildup. Avoid spray-can-style duster products, as they leave a residue that is difficult to remove from delicate optical components. Also, the propellant in these products is usually flammable. This gas should never come in contact with a running projector’s hot components – ask me how I know. A product like the Giottos Rocket Air Blaster can provide a directed blast of dust-flinging room-temperature air without the risk of lens contamination.
Projection for the Masses
Every classroom and learning environment can benefit from the visuals provided by a video projector. While many tempting projection options are available at surprisingly low prices, remember that the least expensive units often sacrifice brightness, resolution, or long-term cost. Not every classroom has a budget for a $5,000+ 4K light cannon, but knowing what features are most important for your particular application can help you avoid a disappointing experience, limited functionality, or unexpected expenses.
Robert is a technologist with over 20 years of experience testing and evaluating consumer electronics devices, primarily focusing on commercial and home theater equipment.
Robert's expertise as an audio-visual professional derives from testing and reviewing hundreds of related products, managing a successful AV test lab, and maintaining continuous education and certifications through organizations such as CEDIA, the Imaging Science Foundation (ISF), and THX.
More recently, Robert has specialized in analyzing audio and video display systems, offering comprehensive feedback, and implementing corrective measures per industry standards. He aims to deliver an experience that reflects the artists' intent and provides coworkers and the public with clear, insightful product information.
- Robert Heronhttps://www.avnation.tv/author/robert-heron/
- Robert Heronhttps://www.avnation.tv/author/robert-heron/
- Robert Heronhttps://www.avnation.tv/author/robert-heron/
- Robert Heronhttps://www.avnation.tv/author/robert-heron/
