It is only possible to measure physical properties of extrasolar planets, if they transit their host stars. One can determine the masses and the radii of this kind of objects, and hence, have constraints on their chemical composition, internal structure, formation and evolution. The availability of high quality light curves of planetary transits is essential in determining these properties within a few percent. In order to obtain high-quality transit light curves, we apply the well-established defocus technique on meter and sub-meter class telescopes in our project. This technique allows longer integration times, and hence collecting more photons to build up a higher S/N ratio. In this study, we present our first photometric results with the 1m Turkish telescope (T100) located at TÜBİTAK National Observatory (TUG) of Turkey, which proved to be a well suited instrument to these observations with its large field of view.