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micrenda

29 Mar 2013 13:05



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The right forumula for object not far at infinite is:

f = (S1 * S2) / (S1 + S2)

This mean that the focal is something like:

f = (45 cm * 250 cm ) / ( 45 cm + 250 cm) =~ 38 cm.

But to be sure, I have to take better measure when there will be a better weather.