Saturday, 14 November 2009

Hawt pixels, anyone?

Has any one tried taking long exposure photos using a digital camera? Some of you do, and some people prefer to use film :P

Anyway, the thing I want to bring up today was the issue of hot pixels. These manifest themselves as bright spots in your digital photo. Most of the time, they are not noticeable because they blend into the subject, but in certain situations, they can be quite obvious.

Take for example this photo below:





The picture above has been sanitised for your protection LOL, ok, I went and cloned out all the obvious spots. But lets look at another picture:






Yeah, the flare in the middle was caused by a passing car, but did you notice the little spots of light under the street lamp, or the one under the red/green flare? Lets take a closer look:





The photo above is a 100% crop from the 2nd photo. Notice the white spots? Those are pixels on my camera's sensor that are malfunctioning. It reads higher than the proper amount of light, therefore it reports that it is being blasted by 1.21 gigawatts of light, and turned white (lol)

This is most noticeable when you set the exposure duration to a vey long time (several seconds or more). For the shots above, my camera was set to 30 seconds exposure.

According to what I've read on the Internet, this is quite common to all cameras. No, this is not the same as noise that you see when you use high ISO. These are actually pixels on your sensor that is not working properly.

What do you do when you find out that you have hot pixels in your photo? Well, you have several choices:

  1. Clone it out using photo editing tools
  2. Ignore them if they're not too conspicuous
  3. Switch on noise reduction mode (if your camera has this function)
  4. Use film :P
So, what would you do?

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