By Stokley Wilson
The last column was about single colored filters. This month's tip is about special effect filters. Special effect filters range from a very subtle effect to a "wild" very strong effect. While I can't possibly describe every filter available, I will cover the most popular styles. If you have a question about using filters not covered in this column, please e-mail your question to this column.
One of the most popular special effect filters is the gradual neutral density filter.
This filter is graduated from top to bottom with a neutral density material, with about one half of the filter being clear. When shooting scenes, we find that we sometimes must compromise our exposure for either the bright or dark portion of a scene. Either we shoot for the dark portion of a scene, and let the highlights be overexposed, or we set the exposure for the bright part of a scene, and let the shadow area be under exposed (black). When using this filter, place the dark part of the filter over the brighter part of the scene. This will reduce the light level in the brightest part of the scene, and the scene will have a narrower contrast range. Here's a tip when using this filter, stop the lens down to see the graduation better.
Also very popular are diffusing or softening filters. These filters reduce the apparent sharpness of a scene. This filter is mainly used for portraits, but can be used in other applications to yield a soft or "painterly" effect.
There are mainly two different styles of diffusion or softening filters, and both have desirable qualities. One of the styles uses a diffusing pattern over the entire area of the filter. Inspecting the filter, you will notice a texture or "orange peel" look over the entire area of the filter. This filter will work with any focal length lens, at any aperture setting. However, it will also lower the contrast in the scene. The dark (black) areas will not be quite so black, almost black, but with a little haze or gray look. Also, the whites will not be quite so bright.
The other style uses small dots, or actually lenses, over the surface of the filter. The dots or lenses shift the focus in only portions of the scene to yield a softer look.
This style of filter must be used with lenses of at least 50mm. Also, you must use aperture setting of f/8 or larger. The advantage of this filter is, there is no loss of contrast.
One of the most asked about filters are the multi-image filters. These filters yield more than one image of the scene through faceted surfaces on the filter. This filter is one of the most expensive styles, and maybe the least amount of versatility. There are two different styles, parallel or radial facets. The parallel style has facets that are parallel in either three, five, or six facets. The image appears like bookends in the amount of facets of the filter used. The radial style has facets arranged around the diameter of the filter. The image appears as a multiple image arranged however the facets are arranged. The three image radial filter looks like the scene split into three images in a pattern like the letter Y. The five or six radial faceted style will yield a normal image in the center, with the multiple images arranged around the center image.
The effect of these filters will be strongest with darker backgrounds and with larger aperture settings. The multi image will appear closer with wide-angle lenses and will appear further apart with telephoto lenses.
Cross screen filters are used to add a cross/flare to the highlights in the scene. This effect is nice with cars, jewelry, and for skylines at night. The length of the flare will be longer with smaller lens opening and smaller with larger lens openings. Use these filters for a little extra "sparkle" or different look to your photos.