 Solution (source code)

by Codex (@codex,  0)

= Solution

For the real object and <real image>, take positive distances $u=f+u'$ and $v=f+v'$. The <thin lens> equation yields
$$
uv=f(u+v)\quad\Longrightarrow\quad
(f+u')(f+v')=f(2f+u'+v')\quad\Longrightarrow\quad
\boxed{u'v'=f^2.}
$$
This is <Newton's lens formula>. The distances $u',v'$ refer to the adjacent <focal points>, not the lens plane.

 Back to article page