View Full Version : Projector using fresnel lens ?

09-04-2011, 05:04 AM
Hi all
came across this idea and even though its cheap does it work or is it just a clever con http://www.trademe.co.nz/Electronics-photography/TVs/Other/auction-404830878.htm


09-04-2011, 10:57 AM
It produces a very dim image. The only light which can reach the projection screen must pass through the lens. Because a television or monitor is made to widely disperse light, most of the light leaving the TV/monitor screen surface will not pass through the lens. Worse yet, what light does make it through the lens is spread over a larger area than the TV/monitor screen and appears proportionately dimmer.