ND2 reduces exposure by 1 level, ND4 by 2 level,ND8 by 3 level,number after ND represents ability of ND lens to block light, suitable for dynamic screens, waterfalls, streams, waves, etc. When lens focusing length is in super wide angle range and aperture value is F2.8, if adjust filter to high density for using, relatively obvious "crossing"spot or slight color shift may occur, to insure that image is not disturbed, we suggest you lower filter density value at this point, until disturbing light spot disappears, then shoot normally.
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