Cokin WA1T139 Series A Gradual FLD Filter

The Cokin WA1T139 Series A Gradual FLD Filter is a rectangular slide-in filter designed for the Cokin A-series holder system. It applies a gradual fluorescent-to-daylight (FL-D) color correction that transitions from a magenta tint at one edge to clear at the other. This makes it particularly useful for scenes where part of the frame is lit by fluorescent light, allowing you to correct the green color cast in that area while leaving the naturally lit portion of the image unaffected. It can also be used creatively to add subtle color gradation to landscapes and other compositions.

Manufactured from CR-39 organic glass — a material originally developed for the optical lens industry — the filter offers excellent light transmission, accurate color rendering, and high resistance to impact. This makes it more durable and easier to handle in the field than traditional glass filters, while remaining extremely lightweight. The A-series format is Cokin's most compact system, best suited for lenses with filter threads up to approximately 62mm, making it a practical choice for photographers using smaller mirrorless or DSLR lenses who want gradual color control without heavy post-processing.