GJ1214b is an extremely interesting 6.55Mearth and 2.6 Earth radii sub-Neptune planet orbiting a M-dwarf host. Its proximity, only 14pc, makes it an excellent target for studies of exoplanetary atmospheres (Charbonneau et al. 2009). Furthermore, the sub-Neptunes/Super Earth-sized planets are only one step between Jupiter-sized and habitable Earth-sized planets with a biosphere. Due to favorable parameters of GJ1214 system, we posses great coverage of many wavelengths in planetary transmission spectra from optical to NIR regions (Miller-Ricci & Fortney 2009). However, the scenarios for the atmospheric compositions are still open. Based on the available measurements, the solar composition (hydrogen rich) atmosphere can be most probably ruled out. That is given by fact that we observe rather a flat spectrum than the absorption features in the hydrogen rich model. Thus, currently more plausible models are atmosphere composed of heavy elements such as water or atmosphere covered by clouds (Bean, Desert, Kabath et al. 2011). Here, we present our spectrophotometric and photometric measurements obtained with SOI and OSIRIS instruments (both SOAR telescope) and SOFI (ESO NTT). We observed 5 transit events of GJ1214b and determined the Rp/Rs ratios for every measured wavelength (Caceres, Kabath, Hoyer et al. 2013). Our photometric measurements at 0.8 micron (Bessel-I) and at 2.14 micron (NIR narrow band) correlate with the flat transmission spectrum, therefore strongly supporting the water or cloudy atmosphere. Our spectrophotometric measurements in the H+K region do not posses the sufficient precision in the Rp/Rs ratios. We conclude that the hydrogen rich model is less probable. However, to be able to decide if the planetary atmosphere is hidden in clouds or if we encountered a water world, we still need more measurements with extremely high accuracy. Here, literally, every new point counts. Finally, we would like to present preliminary results obtained from our 2013 campaign focused at another small exoplanet GJ436b as a demonstration of potential and limitations for ground based transmission spectroscopy.