HELP: Filters and what they're for

[antigravity]

Hi guys, was just wondering on what filters are available and what they're used for.. I was looking through the store catalog and frankly, it didn't offer much of an explanation..
Thanks! :D

[dhbailey]

Circular polarizers are to help get more accurate pictures when there is glare from a reflected surface, such as from car windshields or bodies, surfaces of bodies of water. It removes the glare.

Neutral Density filters allow you to shoot pictures at slower shutter speeds or wider apertures than the actual lighting of the situation will allow without blowing out the highlights and overexposure.

Other filters such as star filters or color filters can often be duplicated in post-processing.

Filter use is something to pursue carefully -- things like the circular polarizer or neutral density filters are good for real-world photography because they enable you to take better pictures. But special effects filters, if used on the camera, may well mean that you end up without a usable picture, if you liked the shot but hated the filter you used. Best, if possible, to simply take the picture plain, and use post-processing software such as PhotoShop or PaintShopPro to apple special effects.

http://tedfelix.com/Photography/Filters.html is a link which explains more.

[DaveG]

Hi guys, was just wondering on what filters are available and what they're used for.. I was looking through the store catalog and frankly, it didn't offer much of an explanation..
Thanks! :D

In the age of digital photography and post production work in Photshop, the need for many different types of filters has been reduced.

The kind of filters that you will still need are:

1) Skylight/UV filters. Optically these filters don't do much. But they will protect the front element of your lens. There is always great debate over whether the UV filter impares the optically quality of the lens, while I suggest that a scratched front element will be worse. In any case I have a UV filter on every lens I own.

2) A Polarizer. You need a CIRCULAR polarizer for a AF camera or it will screw up the AF. You can deepen the colour blue in Photoshop, but it's a different blue than you get with a P filter. You should be aware though that Polarizing filters don't work very well with super wide angle lenses. With a lens like the 10-22 you'll see much more Polarizing effect on one side of the frame than the other.

3) A neutral density filter. These filters are grey and don't affect the colour of the subject. They do reduce the light coming through the filter (Why god, why?) and that turns out to be very useful when you wnt to use slow shutterspeeds under bright conditions. I like to shoot waterfalls, for example. To get the water to that silky steam look, I need eight second exposures and that can't be done without a ND filter.

Back in the days of film, filters were all you could use. In black and white you could choose to use a red filter for example. If you think like a negative, you don't "see" blue very well when it's filtered through red. So everywhere on the B&W neg that saw blue, would be clear. When you print that shot the light comes through the clear part very easily and will print black. That's how you get dramactic black skies with brilliant white clouds (See Ansel Adams). An orange filter would do the same thing but have less effect, and a yellow, even less. But now I'd just do this in Photoshop. The 20D actually has a B&W mode that allows you to choose a "red" filter in the field to do the same thing. But unless I REALLY want to conserve card space with the smaller B&W file size, I'd just as sooon get a colour shot and do all of this later in the computer.

A graduated neutral density filter might be useful to have. But I've found that decoding a RAW file at two different settings (one for the highlights and one for the shadow/midtones) and then blending them together as two different Layers does the same thing and gives me better control.

[Europa]

There is a book by Lee Frost on Filters. Buy it & learn! :D

[antigravity]

Thanks everyone! :D