What are Lumens?

A lumen is a unit of measurement used to quantify the amount of visible light emitted from a source. It is a critical factor when considering a projector and it's specifications for your viewing environment. The brighter the viewing environment, such as a family room with lots of natural, ambient light, the more lumens the projector will need to show a satisfying image. The darker the room, such as a dark home theater room, the less lumens are needed. Lastly, there are different ways to measure lumens, but ANSI and ISO are the only specifications needed to reliably compare projector brightness.

Figuring out how many lumens your projector needs can be a tricky. Learn more about lumens below and in our Spotlight on Lumens article.

How Bright should my Projector be?

The ideal brightness range of your projector depends on the size of the image you desire and the ambient lighting conditions in the room. To optimize your projector's brightness, refer to the helpful tips below.

What is Projector Resolution?

Every projector has a specified resolution that describes how many pixels are used to display the image. The greater the number of pixels, the smaller they will be for a given image size and the more detail is revealed. More pixels also means that the spaces between them will be less visible, and viewers can sit closer to the screen without experiencing any “screen door” effect in which the individual pixels become apparent to the viewer.

The term “native resolution” usually refers to the number of physical pixels on the display chip grid inside your projector. Most projectors up to 1080p (HDTV) resolution are native, meaning that the imaging chip exactly matches the number of pixels that appear on screen. Projectors claiming 4K resolution (3840x2160 pixels), however, may have a 1080p or larger chip whose native pixel count is enhanced by a technique called “pixel shifting” that doubles or even quadruples the number of pixels visible on the screen for higher apparent resolution.

Most 4K projectors today use some form of pixel-shifting to achieve full 4K resolution, though the very best (and most expensive) projectors achieve 4K resolution with a native 4K imaging device. Although a native 4K chip mated with a good lens should provide the sharpest image, projectors that utilize pixel-shifting to keep costs down still deliver very sharp images that most people would be hard-pressed to distinguish from native 4K. Read more about this in "True 4K vs Faux-K".

It’s important to understand that your projector’s native or full resolution specification does not disqualify it from playing video signals with a different resolution. Most modern projectors have very good scaling engines inside to deal with mismatched resolutions, so this should not be of concern.

Read more about resolution in "How Much Resolution is Enough?".

What is the Best Projector Resolution?

Your application and video signal type will determine what the best projector resolution is for you. If you are projecting a large image size of about 100 inches diagonal or bigger, or expect viewers to be sitting close to the screen, a higher resolution projector will serve better. Budget also comes into play, since the cost of projectors goes up as resolution increases.

Particularly among commercial business projectors, resolution is often referred to by a letter code that ends up denoting both the pixel array and the aspect ratio. These days, most business projectors sold are at least WXGA (1280x800 pixels, 16:10 aspect ratio), which matches the wide screen used in modern laptop computers and smartphones. High definition business projectors typically offer WUXGA resolution (1920x1200, 16:10), which also matches with laptops and workstations.

For home theater and portable lifestyle projectors, typical resolutions are 720p (1280x720, 16:9) for budget models, 1080p Full HD (1920x1080, 16:9) in the middle price tier, and 4K Ultra HD for more premium products. Most broadcast and streaming content today is 1080p or 4K UHD.

Refer the information below to see common resolutions and where they might apply.

What is throw distance for a projector?

A projector's distance from the lens to the screen surface is called the throw distance. It will vary from projector to projector based on the characteristics of the lens. A fixed lens with no “zoom” option will always provide the same image size based on its distance from the screen; if you move the projector further way, the image is enlarged; move it closer and the image shrinks. Many projectors have a "zoom lens", which allows you to adjust the image size from any position within its zoom range. Therefore, throw distance is an important criteria for establishing the placement options for your projector and to see whether a particular model meets your requirements.

A projector's throw ratio describes how much the image size changes as the projector is moved, which can be written, for example, as 1.5:1 or “1.5 to 1.” Fortunately, there are tools that can help determine what size image that you can get from a given throw distance without doing any calculations yourself. ProjectorCentral's interactive Throw Calculator provides a graphic representation that allows you to independently adjust your desired image size or distance, and works for more than 10,000 current and pre-existing projector models.

Projector Lenses & Throw Distance

Fixed Lens Projectors

A projector lens with a fixed throw ratio will always provide one image size at a given throw distance.

Zoom Lens Projectors

A projector with a zoom lens will have two different throw ratios, one for the minimum zoom setting and one for the maximum zoom setting allowing for a range of image sizes from a given throw distance.

Long Throw, Short Throw, and Ultra Short Throw Projectors

Projectors generally fall into one of three lens throw distance categories: Long throw, short throw, and ultra-short throw.

Traditional long or standard throw projectors generally project images of up to 200-inches diagonal or larger, but require a longer throw distance that will usually place them across the room. Typical long-throw projectors might end up anywhere from 10 to 20 feet or more away from the screen depending on the desired image size. Many permanent home theater installations end up with a long-throw projector mounted between mid-way and the back of the room.

Short throw projectors have a lens that will create a similarly sized image from a distance much closer to the screen, perhaps as little as 3 to 5 feet. This is ideal for temporary setups where the projector is being placed on a coffee table for a movie or game night, or environments that prohibit mounting further away.

Ultra-short throw (UST) projectors, which are becoming popular for home theater, day-to-day TV viewing, education and business environments, provide a relatively large image from very close to the screen; sometimes less than 1 foot from the lens to the screen and with just a few short inches between the rear of the projector and the screen wall. Image size is typically limited to no larger than 150 inches diagonal. One advantage to a UST projector is that it can be placed directly on a TV stand or entertainment center in place of a typical TV. Its close proximity to source components housed in the entertainment center eliminates long-distance cable runs to a more distant projector location. In a conference room or classroom, they allow the presenter to stand closer to the projected image without casting a shadow, since the projector is not mounted far away where image interference is more likely.