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Rolling Shutter

How to fix Rolling Shutter Effects.

Rolling Shutter refers to one method used to capture images using the camera’s image sensor. 

With a rolling shutter, all the sensor’s photosites (imagine the sensor block is divided into lots of different, small blocks in a grid, that capture parts of the image. These together form the picture) do not capture light at exactly the same time period. All the photosites in one whole row of the sensor collect light simultaneously but subsequent whole rows collect light slightly later than the previous row. In reality the timelag between the rows is incredibly small, however it does mean that the last row of photosites of a camera’s sensor captures light with the most time difference from the first row within one frame of image capture. Unlike the rolling shutter, a global shutter, captures light to all photosites simultaneously and there is no time difference between subsequent rows.

When working with a camera that uses a "rolling shutter" it’s important to plan for the camera movement as the sensors can capture unsightly artefacts when fast camera movements, like whip pans are used, or where the frame includes fast moving objects. These artefacts appear when movements of the objects are perpendicular to the readout direction and happen so quickly that the image position within a read cycle changes. The effect of this can be jagged edges on objects or bends on straight lines. 

Reduction and manipulation of these artefacts is possible within stand alone software tools, or from plugins within popular editing and post production tools.

The following video (soon available in english) explains in detail how rolling shutter works, and what the artefacts look like:


Downloads:
Rolling Shutter Correction UT

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