\bigints package is not working fine together with \lmodern

Question

I'm trying to get big integral symbol, so I tried with '\bigints' but I've found that

\documentclass{article}
\usepackage{lmodern}
\usepackage{bigints}
\newcommand*\norm[1]{\left\lVert#1\right\rVert}
\begin{document}
$$ \bigints \dfrac{\dfrac{1}{2}}{\norm{s}+1} ds =  \int \dfrac{\dfrac{1}{2}}{\norm{s}+1} ds$$


\end{document}

produces

while

\documentclass{article}
%\usepackage{lmodern}
\usepackage{bigints}
\newcommand*\norm[1]{\left\lVert#1\right\rVert}
\begin{document}
$$ \bigints \dfrac{\dfrac{1}{2}}{\norm{s}+1} ds =  \int \dfrac{\dfrac{1}{2}}{\norm{s}+1} ds$$


\end{document}

produces

I don't know the internal code of '\lmodern' so, what's happening?

Answer 1

The fd file for lmodern gives a fixed size for the extension font, you could allow it to be scaled to the current font size.

Although I'd never use the display fraction in the numerator.

\documentclass{article}
\usepackage{lmodern}
\DeclareFontFamily{OMX}{lmex}{}
\DeclareFontShape{OMX}{lmex}{m}{n}{%
   <->lmex10%  was  <->sfixed*lmex10%
   }{}
\usepackage{bigints}
\newcommand*\norm[1]{\left\lVert#1\right\rVert}
\begin{document}
\[ \bigints \dfrac{\dfrac{1}{2}}{\norm{s}+1} ds =  \int \dfrac{\dfrac{1}{2}}{\norm{s}+1} ds\]


\end{document}

The default for cmex is also fixed but amsmath extends that to a larger range (but just for computer modern)