whats the difference betwene a slide projector lense and a magnifying glass?

i need to know pleasseee

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tewharau7 years ago
Conceptually they are the same but designed for different purposes.

The slide projector lens is designed to minimize distortions at its designed focal length (distance between slide and "middle" of lens).  Distortions can be image (straight lines appear curved in the projected image) or colour (colours don't flare out or prism into other colours).

A magnifying glass is designed for maximum magnification and doesn't worry about distortion.

Try this experiment.  Take the slide projector lens and point it out of the window on a bright day, then move a piece of paper closer and closer to the lens until the outside image comes into focus (it will be reversed and upside down).  That is how far you need to place the film from the lens to take a picture or how far your ipod (or slide or LCD) needs to be for it to be projected.

Do the same with the magnifying lens and see if it is suitable. If it works,it works!

I wrote an instructable that may help with an ipod projector


Kiteman8 years ago
Projector lenses are often concave on one side and convex on the other, but are equivalent to biconvex magnifying lenses, and still make good burning glasses.
xadevox (author)  Kiteman8 years ago
yeahh im making an ipod projector. can i just use this glass magnifying glass lense i have?
The projector lense (assembly) will be much more precise and easy to aim/focus than just a single magnifying glass.
xadevox (author)  frollard8 years ago
soooo what about 2 magnifying glasses?
Off top of my head, I couldn't begin to imagine how difficult that would be without doing calculations...