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I am getting some noise in my shots on the black. I wondered if this can be something i can prevent or do I need to clean the image sensor? I am using a Canon T3i/600d/Kiss X5.

The shot was done at night. There was bright reflection on the water which you see to the right, but the tiny white dots to the left look different.

Do I need to just paint them all out with a black brush?

enter image description here

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    Do the same spots appear in the same place in every shot? – Caleb Sep 23 '16 at 16:55
  • Hey @scottbb, no fair editing the answer into the title! ;-) – Caleb Sep 23 '16 at 17:43
  • @Caleb =) I struggled trying to edit the title while keeping it succinct. – scottbb Sep 23 '16 at 17:52
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    Have you tried letting the camera do it? There is a Long Shutter Noise-Reduction setting on most. Check the menu to see if there is such an option. – Itai Sep 23 '16 at 18:22
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    Possible duplicate of What is this dead pixel problem really called? – Michael C Sep 23 '16 at 21:32
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The bad news is that hot pixels are now part of your camera.

You can prepare an action in photoshop cloning each of them with the information next to it, this way you can re apply this clonning with one click next time.

Grab a clonning tool of a small size, 2 or 3 pixels and paint your image, not with black, but with the black that the surrounding has.

You also can try the heal brush.

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Two methods for dealing with hot pixels:

  1. Consider the intended output and if the pixels do not affect it or show up, then ignore them. For example, a printer may not have sufficient resolution or JPEG compression to a lower resolution may eliminate them.

  2. Post-processing with software that provides a hot pixel removal tool either natively or as a plug-in.

It is also possible to limit the likelihood of the hot pixels 'going hot' by reducing the amount of time the sensor is exposed to light. In addition to the somewhat obvious method of using shorter exposure times, avoiding or reducing the use of live viewing modes when composing the shot may also help. Of course, these are trade offs.

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Canon cameras are capable of automatically detecting and mapping out hot pixels (assuming it is bad enough for the camera to detect the problem).

To update the pixel defect mapping table, take the lens off of your camera, put the body cap on, put the camera in sensor cleaning mode, wait about 30 seconds, then turn the camera off and back on.

Repeat this process if the problem doesn't goes away the first time.

  • Do you have an official citation for this? I don't have a Canon camera, but I remember reading that this is an internet myth / wishful thinking — these cameras don't have a secret pixel-mapping function. – mattdm Nov 25 '17 at 12:44
  • I've used it personally to kill a (stuck) hot pixel on my old XTi. But it only works if the pixel is actually stuck on. If the pixel is just a bit hotter than expected, that won't help, and if it is caused by random noise, obviously that won't help. – dgatwood Nov 27 '17 at 18:24

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