We report in this work on a project aimed at determining Ly{alpha} luminosity functions from z=3 to z=6. The project is based on the use of very deep photometry from the SHARDS Survey, in a set of 24 medium band filters in the GOODS-N field. We prese
nt here some preliminary work carried out with four test images in four consecutive bands. We use the narrow band selection technique for searching emission line candidates. Eleven candidates have been detected so far, many of which are strong Ly{alpha} candidates. In particular, we have seen a firm candidate to an interacting pair of Ly{alpha} sources at z=5.4.
