Lesson: Learn about various filters
Goals: Understand when and what filters should be used
Tools: Filters for Camera as well as Photoshop
Filters are used to enhance and/or correctly render a scene from its original state. Filters can be used on the camera and/or on the computer.
In the past, filters have been very popular. But with digital cameras, many filters are somewhat obsolete. One reason, IMHO, is that it is better to capture the image as an original straight (unmodified) image. Appling a computer filter after the fact allows you to keep the original intact. On the other hand, just remember that the more you "save" for the computer...the more time it will take to ever see your pictures as prints. Another reason actual glass filters are somewhat obsolete is due to built in camera controls, such as a white balance, or in-camera effects. However, in-camera effects such as black and white, should be avoided. Under diverse lighting, it is best to shoot in raw so that the white balance can be tweaked at the computer level with out altering the original image. Take for example an alter of a televised church with sun beaming in from stained glassed windows filling in the shadows created by the incandescent lights. While the White balance can also be adjusted for by placing a filter over the flash head, known as a gel.
Several traditional filters are still very effective to use in front of the glass (and even somewhat difficult to reproduce on the computer).
o Polarizer – one of the most popular filters. Reduces reflections and intensifies colors and contrast. Side effect: loss of two stops of light…but this can be a good thing. Remember your Equivalent Exposures to slow that waterfall or get an extra long exposure?
o Neutral Density – helps to reduce exposure by 1, 2 or 3 stops…helpful for portraits outdoors, or waterfalls, etc. In the case of portraits, a ND can help use a larger aperture to achieve shallower depth of field. IN the case of waterfalls, a ND can help to achieve a blurred water effect by allowing a slower shutter speed by 1-3 stops.
o Split Field – are especially effective for the wide range of contrasty scenes we run across. SFs come in two main types: circular (screw on) and square (held on by a holder). The circular are the most convenient, while the square type are the most effective. If you don’t have a filter, see how to mimic the use of split neutral density filters and blending exposures: http://www.fredmiranda.com/article_2/ and http://www.luminous-landscape.com/tutorials/blended_exposures.shtml
o Infrared – although the infrared affect can be simulated, using an IR filters is the most effective.
o Star – always a lot of fun, especially around Christmas time…or for weddings with candles.
o Protective UV or Haze. I personally do not believe in putting even high quality filters on a lens just for protection except in particularly harsh conditions.
o Soft Focus– particularly a spot filter. This filter is easy to make and use…and save a lot of time in the darkroom or computer.
Two filters that are still necessary for film shooters include FLD for shooting daylight balanced color film under florescent lighting…and 80a for shooting daylight film in tungsten lighting (incandescent light bulbs).
Filters take on a different meaning when working in Photoshop. Filters can be applied to all or part of an image, such as turning part of a pictures black and white. There are numerous built in filters that come with Photoshop and PS Elements. In addition, there are many filters that are freeware or can be purchased directly off the Internet very inexpensively.
One of my favorites is to make a selection and apply a Gaussian blur to the background to simulate depth of field. Other filters to try out are any of the Artistic, Distort or Stylize built in filters. Commonly available filters on the internet include: Red Eye Removal and Frames.
o Buy a filter of the largest size lens you plan to own, like a 77mm standard size filter. Purchase stepping rings to fit to other lenses.
o Best place to buy: http://thefilterconnection.com/
o Quality of filters: Not all filters are created equal. Top quality filters will include special coatings to assist with chromatic aberrations and flare. Standard designations may include MC or HMC.
Other: It is important to note that filters still serve a very important role in such things as coating on glass...automotive glass, vision glasses...and sunglasses. UV protection is standard on most glasses...but be careful of ultra cheap glasses. Another sunglass coating is polarizer.
Red filter provides high contrast and dramatic scenic effects with black and
white films. Skies are often rendered very dark with intense, white clouds.
Creates an overall red tint when used with color films.
Filter Factor 8
Exposure Factor 3 stop