The power of dithering for hot pixel removal

I’ve written about dithering before, explaining the principal of how dithering it works and why you should be using it.
In this article I want to show you an example of how powerful dithering is for hot pixel removal and why you shouldn’t be bothered to much by hot pixels.

Modification of Nikon D5100 gone wrong

Before my 2nd trip to Namibia I had my Nikon D600 and the D5100 modified so I could benefit from the h-alpha sensitivity on this trip. Unfortunately I received a message that there was ‘sticky stuff’ underneath the glass filter protecting the sensor and this damaged the chip somewhat. I bought the model second hand, so I guess it was not taken good care of 🙁
When I saw the first shots I took with the D5100 I must admit I was shocked; so many hot pixels everywhere!

Hot pixels single frame
Crop of a single exposure taken with the affected D5100 sensor

Dithering to the rescue

I was quite confident dithering could deal with it, so I decided to keep using the D5100 despite the hot pixels. And sure enough, dithering takes care of all these nasty hot pixels easy enough.
By stacking only 5 dithered frames the hot pixels are almost all gone already!

Stacking only 5 frames already took care of most of the hot pixels
Stacking only 5 frames already took care of most of the hot pixels

Next, tried stacking 10 dithered frames:

With 10 frames nearly all the hot pixels are gone
With 10 frames nearly all the hot pixels are gone

And with just 15 frames all the hot pixels are taken care of;

After 15 frames all the hot pixels are gone
After 15 frames all the hot pixels are gone

Conclusion on hot pixels and dithering

This is a clear example how effective dithering is for removal of hot pixels. So if your sensor has a few (or a lot like mine!) hot pixels; don’t worry! You will hardly see the effect in the final images.

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