I have a silly question.

I'm newbie, I have a silly question.
I noticed that in some photos, the spot light appears as a spoke, certain numbers of lighting rods radiating from the center, like this http://upload.wikimedia.org/wikipedi...-_Dec_2008.jpg

Is it the result of some kind of filter or something?

How to get different numbers of the lighting rods?

I know it's a beginner's stupid question, but I really don't know and want to know.

Thanks.

This effect can happen all by itself when you get a very bright light in the frame.

If you want to get the effect deliberately even with moderately bright light then you can use a cross filter. The glass has a cross scored into it. The number of points on the star depends on the number of lines.

Here are a few examples:

http://www.bhphotovideo.com/c/buy/St...9/N/4294540700

You can also get this effect by stopping down the aperture. Think of looking at a bright light at night, and then squinting.