question about "twinkling" lights

[Abby Rose]

Ok, I'm confused on why when I take a picture of lights with a high aperture it turns out like either of these:

I notice that the lights that are further away have better points on their rays. Why is that?

When these people (and I hope its not against the rules to post links to other peoples pictures, I couldnt find that it was but please tell me if I'm wrong) take a picture of lights with a high aperture, those lights have a lot more points, and the points are pointier.

365 Project : Day 029 | Michael R. Cruz

Bridge in Colour on Flickr - Photo Sharing!

I'm guessing that it has to do with the camera and or lens (I know, good guess, right? :er, but what exactly it could be about them confuses me. And what else?

Please help me understand. And, if there is a proper name for these kind of lights, also tell me that because it sounds silly when I refer to them as "twinkling lights" all the time.

 

[KmH]

Those are called diffraction spikes.

http://en.wikipedia.org/wiki/Diffraction

The aperture in the lens isn't round and the spikes occur where the aperture blades overlap.

How many spikes you get in your images is dependent on the number of aperture blades in the lens.

Rounded edges on the aperture blades help reduce the spikes to a limited degree.