28 July 2011

Quick Lesson on Camera Filters

Susan Brannon
28 July 2011
A Lesson on Filters

You can get some really nice and creative effects using filters during the actual shooting, rather than using your processing software. The filters are used normally for color correction, to compensate the effects of lighting that is not balanced.  For example, a blue filter used in daylight, corrects the orange/reddish cast lighting.  Filters are identified by numbers with vary from manufacture to manufacturer.

Here is a list of typical filters and what they do:

UV Filters:  They are used to reduce the haziness created by ultraviolet light.  They are normally transparent and can be left on the camera for nearly all shots.  They are often considered good for lens protection as well.  A strong UV filter cuts off the violet part of the spectrum and has a pale yellow in color, which are more effective in cutting the haze.

Clear filters:  They are completely transparent in perform no filtering of incoming light.  This is used solely to protect the front of the lens.

Polarizer:  This filter is great for both black and white photography and color.  The filter polarizes the light and reduces reflections, darken the sky and saturates the image more by eliminating unwanted reflection.

Colored filters: They come in almost every color, the yellows are good for portrait image taking while the reds are good for architecture.  Instead of purchasing a filter of every color, I use the plastic filter squares that you use when developing your own film!  I set the filter in front of my lens while taking the shot.  The package for the filters are less expensive than buying each colored filter for your camera and actually quicker to use if you are wanting to play around and take many images using different colors.

Diffusion Filters:  These are also called softening filters that give a misty quality to impart a romantic mood.  They are good for portraits because they soften the wrinkles and blemishes.  They have different levels of intensity, but the milder ones are the best.  They work well with wide apertures because they increase the depth of field and softening effect.

Transparent diffusion:  They are made of tiny globs of acrylic deposited on the surface to diffuse light.  Some globs are inside of the filter and some on the outside.  The filters are used for the dreamy or misty effect.  You can also do this by adding petroleum jelly, optic cement and nail polish to a clear or UV filter.

Neutral density:  has uniform density that attenuates light of all colors equally.  It it normally used for longer exposer that creates a blur or larger aperture, for selective focus.

Split-field density filters:  They have a graduated area of color across the surface.  They typically come in one, two and three stop densities.  they add a tinge of color to the sky, that you can see in magazine ads. 

Star filters: have patterns from point of light sources, such as candles, and sparkles on water.  They come in four, six and eight point configurations.

Grid Filters:  Normally used to provide diffusion effects, for dreamy looks and contrast reduction. The grids on the filter are typically in squares or diamonds made from nylon.  You can also create the same effect by stretching a piece of pantyhose in front of the lens.

Related lessons:
Aperture and f/16 Rule
Shutter Speed Basics

Depth of Field
Focused Bracketing or Photo Stacking

No comments: