B + W 67mm +4 Close Up Glass Filter - NL4
Diopters are optical close up lenses that make macro photography easy.
•When added to a lens they greatly narrow the depth of field while reducing the minimum focusing distance of your lens.
•The effective focal length of the dioptere are:
• +1 = 1000mm
• +2 = 500mm
• +3 = 333mm
• +4 = 250mm
• +5 = 200mm