Filter types - explanation needed!

[PryorKnowledge]

I have tried searching past threads on this forum and cannot find the information that I am looking for

Would someone be able to provide a breakdown of all the different types of filters and their uses?

[hollis_f]

Would someone be able to provide a breakdown of all the different types of filters and their uses?

Well, I don't think I can cover all types of filters as there must be close to 100. Still, here are the most commonly used ones in order of usefulness...

Circular Polariser (CPL). Very useful for making blue skies darker and for removing reflections from water. If you've ever worn polarised sunglasses you'll know what to expect. Watch out for, and avoid, Linear Polarisers - cheaper than CPLs but may screw up your focussing

Graduated Neutral Density (GND). The bottom half of the filter is clear, the top half is grey. Useful for landscapes to make the sky darker so that a single exposure gets the landscape and the sky properly exposed when you'd otherwise have a grossly over-exposed sky. Because you don't normally want your horizon in the middle of the frame, these filters are normally used with a system like Cokin's (do a search for more info).

Neutral Density (ND). The whole filter is grey and blocks out some of the light. They come in different 'strengths' to block different amounts of light. Useful for making long exposures when the scene would otherwise be too bright. Waterfall shots are the best examples.

Tinted Filters: Add a colour to your image. Hardly used as you can achieve the same effect in post-processing on your computer.

UV/'Protective' (POS): Useful for lining the pockets of camera salesmen as they persuade you that you need to spend piles of cash on useless bits of plain glass. Can be useful if you shoot in sandstorms or stormy seas. Can also complete weather sealing on a few lenses if you happen to have a weather-sealed camera. UV filters are doubly pointless as your camera can't see UV light even without a filter.

[Karl Johnston]

www.singhray.com

They have a cool blog on there that shows you which filters do what, gives examples of other photogs using them...check it out.

I use a couple of filters by singh ray myself.

[Wilt]

Digital photography has tremendously reduced the number of filters which are useful to Joe Average. Hollis mentions all of them. The others are typically beneficial to film shooters, most of them for black and white film.

[sapearl]

For the most part, a lot of digital shooters today will get one or more of these three types of filters:

UV Or Skylight - barely effects image coloration, mostly provides physical barrier protection;appears like clear glass.

Neutral Density (ND) - does not impact color temp, but with various coatings will reduce amount of light coming through lens. Some ND's are partial (top or bottom), many are total glass; appears like gray glass, partial or total.

Circular Polarizer (CP) - my favorite and great for landscape shots. It will reduce glare and flare, increase saturation and contrast, render blue skies darker, make clouds "pop" and when used properly will generally improve the overall appearance of the image; appears like gray glass. This filter rotates within it's own construction, allowing you to lighten/darken sky or water.

Some will argue that all filters reduce overall IQ of a high quality lens. This is true if you buy cheap filters, with little or no coating, and use under extreme lighting conditions. My comments above assume high quality filters with excellent coatings. And I'm sure that on a test bench you can measure a supposed drop in image quality for all "add-on" glass. But typically the human eye cannot detect mose of those differences on the better filters. - Stu

[argyle]

Here's a helpful link...the three basic filters needed for digital photography (gimmicky filters not included) are the circular polarizer, neutral density filter, and the graduated neutral density filter, so you can skip over the rest of the filters in the link:

Filters-Thom Hogan (http://www.bythom.com/filters.htm)