they are very good if u need to fill the frame with smaller objects.. at the moment u are limited to the four inches at wide angle "closeness".. any closer and your particular camera will not be able to focus.. for example a matchbox that fills half the frame at four inches would fill the whole frame at two inches..
kinda like zoom in reverse.. instead of useing zoom to make the object bigger u are able to move the camera closer and it will still focus with macro lenses in use.. u can even gang them up.. use more than one to get even closer.. if u want to make something like a bee fill the frame it can be done..
lighting the object can be problem unless u are outdoors thow.. u really can get some remarkable pictures of small objects useing these cheap macro lenses..
if u are into macro photography they will be very usefull and as i have said they dont cost a lot..
trog100
ps.. just to add.. u do need to find ones that match your camera adapter threads.. thow step up step down rings can be used if the match isnt exact.. wether the ones u linked to will or not i have no idea.. they migh be 52 mm but it isnt made clear..