The Cokin Filter A064 Center Spot Violet allows you to emphasize the centre of an image while blurring the surrounding area with a purple colour. This filter allows you to add a dramatic colour effect to your photos.
Working with the Center Spot 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 should 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.