The Cokin Filter P071 Center Spot WA Incolor 2 allows you to emphasize the centre of an image while blurring the surrounding area. This filter comes in two gradations: P070 Incolor 1 and P071 Incolor 2, with the 071 filter having a greater effect than the 070 filter. You can use this filter in combination with colour filters, for example, to obtain an even more dramatic effect.
Working with the P071 filter
The filter is directly influenced by the set aperture and the focal length. If you use a larger aperture, the filter will have a softer effect on the photo. The size of the circular area that will be in focus becomes larger when using a longer focal length. Exposure metering must be done without the filter attached to the lens. If your camera has spot metering, you do not need to remove the filter from the lens to determine exposure.