The sound is acceptable - however, there is no possibility to add an external microphone that is unfortunate. Who wants to film sporting or pas.En daylight, quality is remarkable, for against the night there is a quite disturbing picture noise but in post editing with a good software can improve the rendering (no more) - they are found rechargeable batteries either brand ref samsung slb-10a to 49 euros piece is generic (REF SLB-10A ALSO °) to 7 euros coins !!! I recommend you have at least two spare batteries to be quiet. The housing is waterproof to 60 m (test it before with paper towel in, pay attention to a removable silicon gasket, rinse thoroughly after use like all classics boxes. Manufacturing is robust (aluminum + gum) This is a very good choice for beginners and beginners or who does not want to spend more!
[Edit 19052015] does not use the Digital ZOOM because the quality of the image is deplorable.