What causes a band-like pattern in photos of a CFL?

Question

CFL Image

The image in the above link is that of a compact fluorescent light bulb.

I couldn't figure out the reason for the formation of light and dark bands sort of thing in the image. The same thing happens when I try taking a picture of my CRT TV.

What is the reason for it?

Answer 1

As you are taking this on a phone - it has no shutter, instead it scans the CCD matrix (i think top to bottom) to build an image. What you are seeing is the variation in the brightness of the CFL as the camera scans the CCD. these lamps have a running frequency of around 50-60 Hz, as does the picture on your CRT tv (scan frequency).

Answer 2

AS the CFL has a flickering luminosity with frequency based on the input current (50/60 Hz or a multiple of this value) you may have some effect due to the interaction with the shutter. Try to set your camera in speed priority mode and push the speed up.