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RE: RE: Measuring Focal Length

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Posted by Stephen Campbell on May 27, 2000 10:23:23 UTC

Or you can reflect the image of a light bulb
(without the shade or other light dispersing cover
)at night on a smooth wall or better a black sheet
of construction paper and divide the distance by 2
make sure the image is focused to where you can clearly make out the filament of bulb,do this 2 or
3 times to make sure,or better yet use all the methods described several times.
steve.

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