161A selection of 52mm filters usedto modify the light entering theFZ200 lens.Neutral Density, CircularPolarising and Fluorescent lightcorrection (FLD “Rose”).We have discussed neutral density filters previously when looking atextending the shutter times in order to capture silky flowing water or toset the shutter speed/shutter angle in videography.The first filter that you might want to purchase is the CPL or circularpolarising filter.These work in exactly the same way as the polarising sunglasses wemight wear to reduce glare and reflections in bright sunlight.They work by “cutting” incident light which is reflected back from anobject where the light is 90° to the camera axis. If the light doesn’t reflectback from the subject with this angle the degree of reduction effect isreduced.These CPL filters are almost always round in shape and have a rotatingglass element. The rotation of the filter is necessary for you to view thedegree to which the light is being reduced.Turning the filter slowly whilst observing the image is necessary to findthe point at which the “cut” begins.The angle of “cut” is normally quite small, perhaps only 20° or angularrotation.Circular and linear polarising filters achieve the same effect howeverbecause the camera autofocus relies on polarised light to work properly.Using a linear polarising filter may interfere with the correct operation ofit.Hence Circular polarising filters, which modify the light, are used.
