We present an analysis of the Qatar-1 and TrES-5 transiting exoplanetary systems , which contain Jupiter-like planets on short-period orbits around K-dwarf stars . Our data comprise a total of 20 transit light curves obtained using five medium-class telescopes , operated using the defocussing technique . The average precision we reach in all our data is RMS _ { Q } = 1.1 mmag for Qatar-1 ( V = 12.8 ) and RMS _ { T } = 1.0 mmag for TrES-5 ( V = 13.7 ) . We use these data to refine the orbital ephemeris , photometric parameters , and measured physical properties of the two systems . One transit event for each object was observed simultaneously in three passbands ( gri ) using the BUSCA imager . The QES survey light curve of Qatar-1 has a clear sinusoidal variation on a period of P _ { \star } = 23.697 \pm 0.123 d , implying significant starspot activity . We searched for starspot crossing events in our light curves , but did not find clear evidence in any of the new datasets . The planet in the Qatar-1 system did not transit the active latitudes on the surfaces of its host star . Under the assumption that P _ { \star } corresponds to the rotation period of Qatar-1 A , the rotational velocity of this star is very close to the v \sin i _ { \star } value found from observations of the Rossiter-McLaughlin effect . The low projected orbital obliquity found in this system thus implies a low absolute orbital obliquity , which is also a necessary condition for the transit chord of the planet to avoid active latitudes on the stellar surface .