Projection Lamps and Lenses

Lights and lenses for projectors

Projector Lamps

Lamps or bulbs are essential and the part you’re most likely to need to replace at some point in your projector’s life. Whether you use metal halide lamps or halogen bulbs depends on your projection system; they aren’t interchangeable.

Halogen lamps are much less costly and maintain a consistent brightness as long as they last, but they have a significantly shorter life span and produce a yellowish light. A replacement metal halide lamp will set you back $300 to $400, but it will last 1000 to 2000 hours compared to the 70 hours of life in a halogen bulb. Newer metal halide lamps may last twice as long - up to 4000 hours and more.

Lamp life generally measures the number of hours until your light source is half as bright as it was when it was new. When your metal halide bulb begins to grow significantly dimmer you know it’s losing power. Always test out your new or spare lamp right away because bad bulbs are most likely to fail in their first several hours of use.

Projector lenses

In addition to the standard projector lens, there are special lenses you can purchase that will change the size or shape of your projected image:

• Short throw lenses
• Long throw lenses
• Zoom lens
• Anamorphic lenses

Although this may be an accessory for you to purchase later, providing your projector allows you to attach external or use interchangeable lenses, some projectors will come with special lenses as normal features.

Throw distance refers to the relationship between the size of your projected image and how far your projector sits from the screen. A standard lens will cover one foot of screen for every two feet separating the screen and projector.

With a short throw lens you can project a large image in a small room, whether that’s a small meeting room, class room, home theater or trade show booth. A long throw lens allows you to set the projector far back from your screen - in a large auditorium or church, for example - without leaving you stuck with an impossibly large image.

Zoom lenses make it possible to adjust the size of your image without moving the projector. Long, short or standard throw lenses may come with a digital or manual zoom feature. This is a particularly handy option on portable projectors, making it easy to adapt to a range of screening environments, but watch that you’re not paying a lot of extra money for a limited zoom range (1.2x, for example) that gives roughly the same results as moving the projector a foot or two.

If you’re set on a projector with a 4:3 aspect ratio (or have one already) an anamorphic lens will let you view widescreen presentations or movies without black bars across the top and bottom of the screen or giving you a stretched-looking image. Because it takes full advantage of your projector’s native resolution, instead of wasting pixels on those black bars, an anamorphic lens will give you a higher resolution widescreen (16:9) image. Unfortunately, the lens will treat everything you project in the same way, so any non-widescreen (4:3) source will end up visibly distorted.