What is a filter?

[I_Dralion]

So, you can tell from the title that I am new to photography. Start a college class this quarter. I was reading somewhere here in a forum and now cant find it. Someone was talking about a filter and protecting a lense. Could someone share with me the idea of this and exactly what a filter is. Thanks! :blush2:

[Frog]

A filter is something put over a lens which alters the light entering it and thus the photo.
The thing you heard about protecting the lens is probably a uv filter. There's a bit of debate over these filters as they are not necessary for digital photography, can cause flare especially at night, and don't do that much to protect a lens except perhaps in extremely dusty situations. Why cover up an excellent piece of glass with maybe a not so excellent piece. The excellent uv filters cost a lot.
The necessary filters for digital are polarizer lenses and sometimes neutral density lenses.
If you have a pair of polarized sunglasses, look at the sky when its partly cloudy and you'll see the effect. Mostly they cut glare of reflecting surfaces.
Neutral density filters will make bright cloudy skies balance out with the brightness of the rest of a scene. They come in different gradients. I think most use the Cokin ones which are square and mount to your lens with a holder. They can be slid up and down to get the effect you want. A lens mounted neutral density can't do this.

If you are just starting, I wouldn't worry about them yet. There are probably hundreds of different kinds for special effects but the above two are the only ones necessary for digital and actually not that often. Mostly for landscapers I believe.

[I_Dralion]

Excellent, thanks for the info. I was thinking that but then they were talking about the lense or the autofocus motor and protecting the lense from it. Lots to learn.

[Photo-John]

Hey Matt! Good to see you here

There is lots to learn. Just keep it simple and things will fall into place. I'm excited about you taking a class. You can always check in here and get answers. These forums are a great resource - even for me!

Did you decide on a camera yet?

[I_Dralion]

Hi John, haven't decided on a camera yet. I think I'll wait till after this photography class starts. No rush. I think I'll have a better understanding and will be able to make a better choice once under way. Other then saving a few hundred there seems to not really be a reason not to get the 50D. Or maybe its overkill for what I want... to take killer outdoor pictures and be able to enlarge them. I'm sure you haven't heard the last from me.