Which are the best magnifying filters for a Nikon DSLR with a standard 50mm lens?

Which are the best magnifying filters for a Nikon DSLR with a standard 50mm lens?

If you do not mind colour aberrations at the edges of you images the best would be any diopter kit with a +1, +2 and + 4 set.

If you really want to shoot close ups with a 50 mm lens, an extension tube would be the best choice… With an extension tube, you will not degrade the image at all. Pick one that has electrical contracts so that the camera can communicate with your lens

If you are looking at macro, the only acceptable filter in my view is the Canon 500D macro filter. It is surprisingly quite good; at least compared to the typical filters - which are junk.

However, at $150+, they are pretty expensive, and in the ballpark cost-wise of other solutions such as Kenko extension tubes (the ones with electrical contacts).

And lest we forget, you can get into a true 1:1 macro lens for under $300 with the Nikon AF-S 40mm f/2.8 micro. While this lens is really not appropriate for bugs - as you have to get so close - it works pretty well for macro shooting of everything else.