Filters on the Camera vs. Post Processing
Nowadays it’s all different. There are still a couple of filters that are useful. But so many of the effects and corrections that used to be made with filters, are now made or created electronically within your camera or using software after you have taken the photo and it is on your computer screen. What you can do with Photoshop, Photoshop Elements, Lightroom, Aperture, iPhoto, NIK filters and any number of other programs on your computer is quite amazing. It is much more than expert darkroom technicians and retouchers could do in earlier days. Photography magazines used to be filled with ads for filters and filter systems that could create all sorts of effects from darkening skies to creating odd color casts or psychedelic effects.
In this article, we are going to consider what, if any, filters you should use when taking photos, and what you don’t have to worry about because you can take care of it in the camera or after the fact.
Vital filters
There is one type of filter which no amount of digital wizardry will replace. That is the piece of glass that you attach to your expensive lens to protect it from getting scratched or damaged, sprayed with salt water and so on. If you’re going to spend $500 or $1000 on a lens, it’s a good idea to protect it. There are various types of filters which are used for this purpose, chief among them are a UV (ultraviolet) and a Skylight Filter. Their effects on the photo are negligible. They are there because you want to protect your lens. If you damage the filter, it’s only a matter of $15 or $30 to replace it. The type of filter is not critical but you should get one that is made of good, optical glass, not a cheap piece of bottle glass. Anything you put between the lens and your subject will have some effect on the image quality. What’s the point of buying a $1000 lens and then putting a piece of cheap glass or plastic in front of it? It is self-defeating. So whether the filter you get to put in front of your lens is a UV filter, a Skylight filter or just a piece of clear glass, make sure it’s the best quality.
Another useful filter which you may want to keep in your gadget bag is a polarizing filter. This consists of two pieces of glass that rotate in relation to each other and have the effect of cutting out stray rays of light. This has two main uses. It helps cut down reflections and glare off non-metallic surfaces (reflections in glass, shiny highlights on leaves, grass, water, etc.) and it intensifies colors. This is noticeable in a blue sky with clouds; the polarizer will intensify the blue and increase the contrast. It affects many different colors.
Even here we are arriving at the borderline between optical and digital. There is a digital polarizing filter (NIK provide one, for example, in their ColorEfex package). It accomplishes some of what a glass polarizer will do, but not all of it. It will not do remove reflections in glass and so on. It will intensify the colors.
Other filters
There are filters used in Black and White photography, mostly to increase contrast and darken certain colors selectively (such as the blue of a blue sky).
There are soft focus or diffusion filters which can create a dreamy look much favored by certain photographers.
There are color cast filters which create an overall color cast.
There are color correction filters to correct white balance.
There are neutral density filters which are used to cut down the amount of light entering the camera without affecting the color or anything else.
There is a star or cross screen filter which has lines scratched in the glass. When you use that and there are point sources of light in the photo (sun, spotlights, reflections of the sun on water, etc.) the star filter will create lines of light radiating from these point sources. It can be overdone but also can create a great effect when used appropriately.
There is a digital version of the above. It may or may not be as effective.
All of the others mentioned above have their digital counterparts, either built in to the camera or which you can use on your computer,
And so on….
But do you need them?
Just about everything that can be done and used to be done with glass or plastic filters attached to the front of your camera, can now be done electronically inside your camera or on your computer after you have taken the photo.
You can correct the color. You can increase or decrease contrast. You can soften or sharpen. You can convert color to Black and White. You can add color casts, darken the sky, lighten the sky, make the greens greener and the reds redder and so many other things that used to be done with filters. It is actually mind boggling and doesn’t really come home to you until you get a program like iPhoto or Photoshop Elements and start playing about with them. Then there are companies that make whole sets of digital “filters” which you can add to Photoshop or other programs or use independently. There are many, many such companies and filters available.
Bottom line
There is no substitute for a good piece of glass in front of your expensive lens to protect it (under the guise of a UV filter or a Skylight filter or whatever – it’s virtually clear, high quality optical glass which will protect the front of your lens without degrading the image quality.) It’s a good idea to have one of these on each of your lenses (except perhaps where the lens is very recessed in the barrel so the front element is not exposed at all, such as in some macro lenses, and obviously not with some fisheyes where the lens sticks out beyond the filter ring).
A polarizing filter is still very useful and cannot entirely be replaced with digital alternatives. It’s worth having one or two of these in the different sizes of the lenses you use the most.
Other than that, if you have the software on your computer, it’s not really worth the trouble or expense. There are some exceptions probably but in the main, you just don’t need that huge battery of filters which used to be part of every pro or advanced amateur photographer’s kit bag.
So next time you are reading an ad in a magazine or listening to the salesman in the camera store telling you just how much you need this or that filter, think twice!
Good news, isn’t it!
David © Phillips is a professional writer and photographer living in Seattle, WA. You can find out more about him and his work at www.dcpcom.com