Hi,
 
I have asked this question on tex.stackexchange.com
 
http://tex.stackexchange.com/questions/113592/formulas-in-context-are-different-from-those-in-plain-tex/113609?noredirect=1#comment250549_113609 

 
as the title said, formulas typeset by ConTeXt are different from those by plain TeX.
The minimal examples are here:
 
% plain luatex in ConTeXt standalone
 
$$\int_a^bf(x)dx=F(b)-F(a)$$
\bye
 
% context
 
\starttext
\startformula
\int\nolimits_a^bf(x)dx=F(b)-F(a)
\stopformula
\stoptext
 
Marco said to me that that's because the fonts used by LuaTeX and ConTeXt are different. This can be seen from the pdf produced by them
 
pdffonts context.pdf
name                                 type              emb sub uni object ID
------------------------------------ ----------------- --- --- --- ---------
OLAZTU+LMRoman12-Regular             CID Type 0C       yes yes yes     18  0
RXHAAY+LatinModernMath-Regular       CID Type 0C       yes yes yes     19  0
JTHTZJ+LatinModernMath-Regular       CID Type 0C       yes yes yes     20  0

pdffonts plain.pdf
name                                 type              emb sub uni object ID
------------------------------------ ----------------- --- --- --- ---------
APMHZE+LMMathExtension10-Regular     Type 1            yes yes no       4  0
AWBTPY+LMMathItalic7-Regular         Type 1            yes yes no       5  0
ITITNI+LMMathItalic10-Regular        Type 1            yes yes no       6  0
DMNVHT+LMRoman10-Regular             Type 1            yes yes no       7  0
MGKPYK+LMMathSymbols10-Regular       Type 1            yes yes no       8  0
 
even if using the `modern-designsize-virtual` typescript(advice from Marco), I still get the different outputs.
 
Now, I get confused about this qustion. If ConTeXt uses LuaTeX as its engine, how can I tune ConTeXt so that it can produce the same formulas with those in plain TeX? 
 
Tim