  We report intensity variations of different spectral components in the BL Lac
object S5 0716+714 detected during coordinated BeppoSAX and optical
observations in 1996 and 1998. The transition between synchrotron and inverse
Compton emission has been clearly detected as sharp X-ray spectral breaks at
around 2-3 keV on both occasions. Correlated optical and soft X-ray variability
was found during the second BeppoSAX pointing when intensive optical monitoring
could be arranged. The hard (Compton) component changed by a factor of 2
between the two observations, but remained stable within each exposure. During
events of rapid variability S5 0716+714 showed spectral steepening with
intensity, a behaviour rarely observed in BL Lacs. We interpret these findings
as the probable consequence of a shift of the synchrotron peak emission from
the IR/optical band to higher energies, causing the synchrotron tail to push
into the soft X-ray band more and more as the source brightens.
