I would like to know how to adjust the gap between a widehat and the letter beneath. Here is a minimal working example:
\documentclass[a4paper,10pt]{article}
\usepackage[T1]{fontenc}
\begin{document}
\[
E_{\hat{\lambda}}(\lambda) D_{\hat{\lambda}}(\lambda)F_{\hat{\lambda}}(\lambda)
\]
\[
E_{\widehat{\lambda}}(\lambda)D_{\widehat{\lambda}}(\lambda)F_{\widehat{\lambda}}(\lambda)
\]
\end{document}
The \hat's in the first line are too small to be properly distinguishable. On the contrary, the \widehat's in the second line are too big and do not seem to belong to \lambda anymore because of the big gap between them.
Any idea to make this formula look better ? In particular, I need to reduce the gap between the \widehat's and the \lambda. In addition, I would like the size of the hats to be somewhere between the size of \hat's and of \widehat's. Any help would be greatly appreciated.

\usepackage{amsmath}. – egreg Feb 23 '17 at 12:59lmodern, check Strange behaviour of\widetildein integrals – egreg Feb 23 '17 at 13:41