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Tuesday, June 3, 2008

Why do people look so big on a film screen?

When we pass light through a film on to a screen a little distance away, we obtain a picture which is larger than the film itself. This is because there is a magnifying lens at the ends of the projector. The size of the image depends on the distance between the projector and the screen, and on the focusing power at the end of the projector. Projectors also have a system of lenses which help to make the picture clearer and sharper.

2 comments:

Felipe June 4, 2008 at 12:17 PM  

[1/f = 1/p' + 1/p] where f is focus, p' is the image distance and p is the object distance, both from the projector lens.

pilo June 17, 2008 at 7:27 PM  

I think that's because in a screen, you 're looking in only 2D. When you look a flat image, it would look wider that if the image have a depth (background) or a third dimension. In a screen, the depth is always missing (or is hard to notice), and that's why an image seems flat, and so more fat than in real life. Because of the absence of depth.

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