What causes blurriness on a camera?

Answer 1

Blurred images can be caused by:

* Camera shake * Poor focus * Dirty lenses or filters * Shooting through windows * Moving objects in the image The most common cause is poor focus. This can be caused by not allowing the camera to autofocus before taking the photo, or by manually focusing the camera when wearing corrective lenses (or not wearing them). Another common cause of poor focus can be the camera focusing on something besides the subject. To avoid these problems, take pictures in as much light as possible, and get in close.

Answer 2

because divjot wants them to

...no

And remember, the camera does not get blurry, the camera only captures light the way you tell it to. Or, at least, that's how it used to be. The three basic operating principals in a camera are the aperture, the shutter speed, and the ISO. The aperture is a ring inside the lens, which controls how much light is let in. The ISO is the film speed, and for the sake of simplicity, just trust me that it controls how bright or dark the picture is. And, there's the shutter speed. This is the factor that controls how blurry a picture is. If you have a camera set on a faster shutter speed, then the camera will take in less light in a smaller frame of time. It will be a darker, more crisp picture. To correctly expose a picture in a lower light situation, a point and shoot camera will increase the shutter speed, or the length of time the sensor is exposed to the light. This will make it bright enough that you can see it, but it will also be blurry. Other ways you can make a picture brighter are by increasing the ISO, or lowering the f number (opening the aperture, letting in more light, blah blah blah). If you do these things, you can use a shorter shutter speed and get less blurry pictures.

TLDR: Because shutter speed.