Home Theater Projector Buyer's Guide: Installation & Placement

The best projector on earth is useless if it doesn't fit in your theater. To make projectors easier to fit in to a variety of rooms and help them accommodate different screen sizes, many projectors now incorporate zoom lenses and physical lens shift.

Zoom Range

A zoom lens is able to make the projected image larger or smaller by shifting the internal optical elements of the lens. This allows a projector to deliver the desired image size from a range of throw distances. Some projectors have a very limited zoom range. For example, a 1.20:1 lens, sometimes noted as 1.2x, means the maximum image size is just 20% larger than the minimum size. On the other hand, some projectors have zoom lenses of 2.0:1, or 2.0x, meaning that the maximum image size is double that of the minimum image size. Such a lens provides a lot more flexibility to create the image size you want from the place you want to locate the projector.

Though long zoom ranges offer great flexibility, the projector's potential light output usually drops somewhat if you use the telescopic end of a long zoom lens. So if you want to maximize light output, it is best to avoid the longest throw distance the lens will allow.

In your search for the right projector, first determine the size of the image you want on the wall. Then use the Projection Calculator to see if the model you are looking at will create that size image with the room size and throw distances you have to work with.

Lens Shift

Another feature that makes installation easier is lens shift. The ability to move the lens up or down, left or right, while keeping the projector stationary lets you change the location of the projected image on the wall. This makes it a great deal easier to place the projector where you want it, and adjust the lens so that the image fits your screen perfectly. If you do not have any lens shift capability, you will need to take extreme care to position the projector at the precise location demanded by its fixed throw angle.

If the projector does not have lens shift, one alternative is to tilt the projector such that the image fills the screen from the position you want to place the projector. However, this will result in a trapezoidal shaped image. You can square it up using keystone correction, but this is something you should avoid if possible since it can soften the image a bit.

Vertical lens shift moves the image up and down, which allows the projector to be placed at different heights and still properly light up your screen. The range of shift varies by projector, anywhere from a modest range of half a screen height, to a typical maximum of about three screen heights. If you plan to install your projector on a rear wall so that the projector is about the same height as the screen, you only need a modest lens shift range. On the other hand, if you plan on ceiling mounting your projector and having it throw the image downward to the screen, a more extensive vertical lens shift range is required. Without lens shift, it is sometimes possible to ceiling mount the projector in the precise location dictated by its fixed throw angle. However, this often requires the use of a drop tube to distance the projector from the ceiling while maintaining your preferred screen height.

Horizontal lens shift moves the projected image from side to side, which enables the projector to be placed off-center from the screen. While horizontal lens shift is not normally as extensive in its range as vertical shift, it does allow for some movement, which is crucial if you cannot place your projector in line with the center of your screen. Horizontal lens shift can vary between 5% and over 50% of a projected image's width, and it is much less common than vertical shift. In order to illuminate a home theater screen evenly, the projector should be as close to the center axis of the screen as possible.

The availability of vertical and/or horizontal lens shift on a given model is noted in ProjectorCentral's database, but the specific range data is not. However, these specifications are always discussed in ProjectorCentral reviews. They can also be found in the Owner's Manuals, many of which are online. When they are available, you will find a link to them from each model's specification page in the database.