# geometry package - setting margins on a specific page

I want to set the first page's margins differently from the rest of the document. What is the best way of doing this? I am using geometry package to adjust my margins.

Any help is appreciated, thank you.

\documentclass{article}

\usepackage[margin=1in]{geometry}
\usepackage{lipsum}
\usepackage{afterpage}

\begin{document}

\newgeometry{margin=0.5in}
\lipsum[1]

\clearpage

\restoregeometry

\lipsum[2-20]

\end{document}