kpfonts and Computer modern

there are typographical contraindications to use kpfonts for the text and standard Computer modern for the Math mode?

\documentclass[a4paper]{memoir}

\usepackage[nomath,fulloldstylenums,fulloldstyle]{kpfonts}

\begin{document}
ciaostffi

$\int a+b=c^2\sum\partial\nabla\psi\ell$

\end{document}

-
It's always better not to mix fonts in the text body. If you type a variable name or inline formula, it will definitely look awkward. May I ask why you want two different fonts? –  Timothée Poisot Aug 10 '12 at 14:24

use

\documentclass[a4paper]{memoir}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[nomath,fulloldstylenums,fulloldstyle]{kpfonts}
...


then you'll get:

voss@shania:~/Test> pdffonts test.pdf
name                                 type              emb sub uni object ID
------------------------------------ ----------------- --- --- --- ---------
JONXPB+Kp-Companion-Regular          Type 1            yes yes no       4  0
SDCAJC+Kp-Regular                    Type 1            yes yes no       5  0
YPARFD+Kp-Expert-Regular             Type 1            yes yes no       6  0
WHFDFR+LMMathExtension10-Regular     Type 1            yes yes no       7  0
IPZDPD+LMMathItalic10-Regular        Type 1            yes yes no       8  0
NZUYHE+LMRoman10-Regular             Type 1            yes yes no       9  0
SDXHST+LMRoman7-Regular              Type 1            yes yes no      10  0
HXDVWF+LMMathSymbols10-Regular       Type 1            yes yes no      11  0

-
It is certainly the case that the kpfonts text-mode and math-mode fonts are quite different from their Computer Modern and Latin Modern counterparts. The Kepler font, being derived from the famous Palatino font, is best classified as "oldstyle" or "Garalde". The Computer Modern fonts are, well, "modern" in style. Three of most readily apparent differences are: