[exim] exim4 logging

Hello,

I've been running exim4 for more sometime now and I have to say I'm very
happy with on the whole. Having said that I'm interested in turning down the
level of detail to which it's logging but I can't find the option (e.g:
log_level) under Debian in a split configuration and I would welcome any
help on the subject...

Many thanks.

Hugh