The Cokin Z-PRO 140 Oval Center Spot/White Resin Filter have an oval-shaped clear spot in the center and allow for the portrayal of an object in diffused surroundings. This white filter not only softens details but also lowers contrast.
The filter effect is directly influenced by the f-stop and the focal length. The transformation is softer with wider apertures. The size of the clear circular area increases relatively with the selection of longer focal lengths.
Z-PRO Filters are made of CR39 Resin which is a reputable lightweight and unbreakable optical material also used for ophthalmic glasses. The Z-PRO Series is recommended for focal lengths of 20mm onwards (in the 35mm format).
Note: The exposure determination should be done without the filter