
The B+W 52mm Close-Up +4 (NL4) Filter is the right power for closer focusing with a 50mm lens (up to Approx. 1:3) when you have reached the limit with the NL 2 lens. With 85mm (up to Approx. 1:2.1) & 100mm (up to Approx. 1:1.9) telephoto lenses, it is the highest power, & it should be used with the main lens stopped down to at least f/8.