Electronic Shutter and Bendy Propellers ?

Started Jun 29, 2014 | Discussions thread
Guy Parsons
Guy Parsons Forum Pro • Posts: 30,591
Electronic shutters.

Sensor scans done as electronic shutter are essentially the same as the mechanical focal plane shutter but happens a lot slower.

The older sensors take about 1/10 second to scan, that is evidenced in fact on my Oly E-PL5 as the shutter closes for about that 1/10 period after a shot so the image can be scanned off the sensor and into the buffer.

The focal plane shutter rushes across the sensor in about 1/400 second so is a bit quicker than the electronic scan. At higher shutter speeds, the shutter still moves at exactly the same speed across the sensor but the second curtain so closely follows the first curtain that it is only a narrow slit that passes over the sensor when you get to say 1/2000 second shutter speed.

The electronic shutter does the same trick, electronically controlling the exposure by how many rows of pixels are exposed (switched on the receive light) for how long as the slow 1/10 scan takes place (faster on GM1 and GH4 of course), so again it is exactly equivalent to a travelling narrow slit going across the sensor (at high shutter speeds) but controlled electronically instead of by the mechanical shutter. It just happens to be a lot slower moving than the mechanical shutter and thus the bendy effects happen because the top of the image is a ahead or behind in time, depending on whether the scan is up or down the sensor.

Maybe that helps explain things.

The ultimate that most are waiting for is the global shutter where the whole image is exposed and unloaded in one go thus eliminating the bendy effect, no travelling slit any more, be it mechanical or electronic. But we are still waiting....... and waiting......

Regards.... Guy

 Guy Parsons's gear list:Guy Parsons's gear list
Olympus PEN E-P5 Olympus PEN E-PL1 Olympus PEN E-P3 Olympus PEN E-PL5 +2 more
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