Frame Rate/Shutter Speed Question.

Started Jan 6, 2013 | Discussions thread
Sean Nelson
Sean Nelson Forum Pro • Posts: 12,517
Re: Frame Rate/Shutter Speed Question.

LifeIsAVerb wrote:

So, as i understand it, light hits each of the photosites and the sensor generates an electrical proportional to the amount of light it receives. I assume that this information has to be stored somewhere prior to it being transferred to the card. Is this in the sensor itself, or in a separate device? What does "sensor clearing" mean in this context?

The "data" for each pixel is stored on the chip inside the structure of each photosite on the sensor.  Each photosite contains a photodiode that receives photons and converts them iinto electrons - those electrons then accumulate in the gate of a read-out transistor.  A special "reset line" is connected to all of the gates in a single row on the sensor - when that line is activated it dumps the accumulated charge for all the pixels in the row so that they're ready to "start" a new exposure.

If anyone knows of some online references that explain these kinds of sensor mechanics in a clear way, it would be much appreciated.

There's an electrical diagram of the construction of an individual photosite on this Wikipedia page, although it may or may not count as the "clear" description you're looking for...

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