  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 present 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.
