Light output affects how well an image can be viewed and is measured in lumens. For a typical office, a projector's light output should be between 2000 to 4000 lumens. If the overhead projector will be used with an LCD panel, at least 4000 lumens is recommended. Since there is no standard measurement for lumens, it is always best to test the unit under the conditions you expect it to be used most often. Also think about the room in which the projector will be used.
Focal length determines the size of the projected image.
Most standard lenses have a focal length of 14 inches, or 355 mm, which is right for distances of 8 feet to 10 feet. These features are definitely worth paying for since they can help minimize the damage that can result from overheating. Other useful options include a document feeder that will switch transparencies on cue, a second bulb which can be switched to immediately if the first one burns out, and stare shields which reduce the amount of light that shine into eyes. Earliest info on new businesses, homeowners Sales Prospecting Center Real info, real opportunities. Merchant Services Start accepting credit cards online.